ABSTRACT Oral Presentation (2) Academic research paper on "Clinical medicine"

MINI ORAL SESSION 01

VENTRICULAR TACHYCARDIA & VENTRICULAR FIBRILLATION

MO 1-01

OPTIMAL DURATION AND PREDICTORS OF DIAGNOSTIC UTILITY OF PATIENT -ACTIVATED AMBULATORY ECG MONITORING

Eugene S.J. Tan, Swee Chong Seow, Pipin Kojodjojo, Devinder Singh, Wee Tiong Yeo, Toon Wei Lim

National University Heart Centre Singapore, Singapore

Introduction: Patient-activated ambulatory ECG monitors have been widely used in the outpatient setting for patients with infrequent symptoms. The optimal duration for diagnosis and the predictors of detection remain unclear

Methods: Patients with palpitations or dizziness received a patient activated handheld ECG monitor which records 30 seconds single leac ECG strips. Patients were monitored in an ambulatory setting for a range of 1-4 weeks and rhythm strips were interpreted by 5 independent electrophysiologists. Event pick-up rates and clinical covariates were then analysed.

Results: Of the 335 adults (age 50 + 16 years, 58% female) with palpitations (90%) and dizziness (25%) who were monitored, 288 patients (86%) reported events, with 73 (25%) patients having clinically significant events detected (Figure). 7% of patients had ^2 significant events and 75% of patients had events detected in the first 3 days. No significant events were detected after 12 days. The most common ECG abnormalities detected were premature ventricular ectopics (39%), premature atrial ectopics (38%) and atrial fibrillation/flutter (33%). Predictors of a clinically significant event included age, irregular rhythm, known AF or arrhythmia and previous abnormal ambulatory monitoring (all p<0.05). Patients older than 50 years were 84% more likely to have a clinically significant event (p=0.02).

Conclusions: Patient-activated ambulatory ECG monitoring for 2 weeks was optimal in the diagnosis of patients with palpitations as significant events first detected beyond 10 days were rare. Patients older than 50 years were more likely to have a clinically significant event.

Figure. Patiem character! tics (11=335)

Dejected event No detected event P value

N 84 251

Clin kal cwariates

Ass. years 54 ±17 49 ±16 0.03

Palpitations (%) 19(96) 224(93) 0.23

Known AF (%) 12(14) 6(2) <0.001

Other arrhythmias (%) 22(26) 22(9) <0.001

fte vious event monitoring (%) 33 (39) 63(27) 0.04

Previous abnormal event moniiotinE (%) 21(25) 15(6) <0.001

Beta-blockers 37(44) 63 (27) <0.01

Reported event 82(98) 204(81) <0.001

Type of event

Sinus tachycardia 1(2) 33 (15)

AF.'flutter 2S (33)

SVT 7 (S)

AT «(7)

PAC 32(38)

PVC 33(39)

AVE; sinus arrest 2(2)

Ectopic atrial itiMlim Kl)

=2 typesof events 22(26)

Tune to first detected event (n=73)

0 to 3 days 53(73)

4 to 7 days 12(16)

S to 10 days 4(6)

11-14 days 4(6)

=15 days 0(0)

Duration of REKA 0,046

1 week 0(0) 20(8)

2 weeks 79(94) 211(84)

3 weeks 5(6) 19(8)

4 weeks 0(0) 1 (0.4)

AF, atrial fibrillation; SVT, supraventricular tachycardia; AT. atrial tachycardia; PAC prematura atrial tachycardia; PVC. premature ventricular tachycardia; AVB. atrioventricular block

P values obtained by independent T test or chi-square test

VENTRICULAR TACHYCARDIA & VENTRICULAR FIBRILLATION

MO 1-02

THE RATIO OF AVL/AVR IS SIMPLE IN DISTINGUISHING VENTRICULAR ARRHYTHMIAS ORIGINATED FROM THE RIGHT AND THE LEFT CORONARY CUSP

Hong-wei Tan, Xu-min Zhang, Yu Zou, Jian Zhou, Jian Zhou

Shanghai East Hospital Affiliated to Tongji University, Shanghai, China

Introduction: Idiopathic ventricular arrhythmias (Vas) are commonly originated from right coronary cusp (RCC) and left coronary cusp (LCC). Several previous studies have revealed differences in the electrocardiographic characteristics of VAs originating from RCC and LCC. However, the electrocardiographic criterion for distinguishing these arrhythmias is still to be elucidated and the utility of aVL/aVR ratio is unknown.

Methods: We studied 21 consecutive patients (mean age 56+16 years, 5 male) who underwent successful catheter ablation for idiopathic VAs originated from RCC (n=6) and LCC (n=15). QRS waveform, duration and amplitude from standard 12-lead ECG were measured.

Results: All patients with RCC VAs presented with R morphology in lead I, whereas for patients with LCC VAs, 4 presented with QS morphology, 10 with RS or rs morphology and 1 with R morphology (x2=16.80, p<0.01). All patients demonstrated with R morphology in inferior leads and QS morphology in aVR. 2 patients demonstrated QS morphology and 4 with rS morphology in lead V1 for patients with RCC VAs, while for patients with LCC VAs, 4 present QS morphology, 7 with rS morphology, 3 with qrS morphology and 1 with R morphology. The QRS duration in lead aVL was significant longer in patients with LCC VAs than in patients with RCC VAs (129 +18 ms vs. 102+22 ms, p<0.01) and the QRS amplitude in lead III, aVL and aVF was significant higher in patients with LCC VAs compared to patients with RCC VAs (1.85 + 0.43 mv vs. 1.70+ 0.38 mv, p<0.01; 1.19+0.24 mv vs. 0.61+0.21 mv, p<0.01; 1.98+0.36 mv vs. 1.51+0.36 mv, p<0.05). Compared to patients with RCC VAs, III/II ratio and aVL/aVR ratio were significant higher in patients with LCC VAs (1.09+0.12 vs. 0.79+0.11; 1.31 +0.35 vs. 0.61+0.22, all p<0.001). The ability of aVL/aVR ratio to distigush LCC VAs was assessed by using an ROC curve. The ares under the curve for the ROC curve of aVL/aVR ratio was 0.967 [95% confidential interval 0.892-1.000]. An aVL/aVR ratio of more than 1.0' had 80% sensitivity and 100% specificity for detecting patients with LCC VAs.

Conclusions: A relatively large R wave in lead I is seen in RCC VAs. Patients with LCC VAs showed longer QRS duration in lead aVL anc higher QRS amplitude in lead III, aVL and aVF than patients with RCC VAs. The ratio of aVL/aVR >1 is a simple and reliable index in distinguishing VAs from LCC and RCC.

BASIC/TRANSLATIONAL SCIENCE

MO 1-03

SYMPATHETIC NERVE BLOCK ATTENUATES INFLAMMATION-INDUCED ARRHYTHMIA VIA A CHOLINERGIC ANTI-INFLAMMATORY PATHWAY

Hyelim Park1, Hyewon Park1, Hyo-Eun Kim1, Seung-Hyun Lee1, Michael Kim2, Hui-Nam Pak1, Moon-Hyoung Lee1, Boyoung Joung1

'Yonsei University Health System, Yonsei University College of Medicine, Seoul, Republic of Korea; 2Duke University, Durham, United States

Introduction: Recent research has shown that sympathectomy and pharmacological sympathetic blockades are effective treatments for fatal arrhythmia. The cholinergic anti-inflammatory pathway (CAIP) is a complex immune mechanism that regulates peripheral inflammatory responses and can be triggered by the central nervous system. This study evaluated the antiarrhythmic effect of sympathectomy is related with the activation of CAIP using experimental autoimmune myocarditis (EAM).

Methods: Experimental autoimmune myocarditis (EAM) was produced by injecting 2 mg of porcine cardiac myosin into footpads. Fifty-twc rats were assigned to the normal control group (control, n = 10), the EAM group (Myo, n = 15), the sympathectomy plus EAM group (MyoSB, n = 15), the B-blocker pus EAM group (MyoBB, n=9), and the only sympathectomy group (SB, n=8). Relevant signaling pathways were studied to compare their effects on myocarditis, survival rate, histopathological changes, ultrastructural changes, electrophysiological changes, and cytokine levels.

Results: In the Myo group, 4 (27%) rats died suddenly at 14+4 days after acute myocarditis and 7 (47%) surviving rats had arrhythmia. However, no rat died and had arrhythmia in the control or MyoSB groups (all p=0.02). Compared with control, left ventricular dysfunctior and higher levels of inflammation such as Cox2, iNOS, TNF-a, IL-6, and HMGB1 increase (p<0.05 vs. control) and increased fibrosis with slower conduction velocity (CV; p<0.01 vs. control) were observed in Myo, but not in MyoSB. Compared with control (100%), the Myo group showed reduced phosphate/total STAT3 (0.5 + 0.1 times, p=0.001) and JAK2 (0.5+0.0 times, p=0.01). However, compared with Myo, MyoSB showed significantly enhanced JAK2 activation (2.2 + 0.1 times, p<0.001) followed by STAT3 phosphorylation (2.2 + 0.2 times, p<0.001) with the increased secretion of acetylcholine (105+1%, p=0.03). In addition, the same trends in levels of protein expression were observed m the lungs, liver and spleen containing innate immune cells.

Conclusions: Sympathectomy increased survival and showed antiarrhythmic effects along with the reduction of inflammation in EAM models via activation of the JAK2-STAT3-mediated signaling cascade. It represents an exciting opportunity to develop new and novel therapeutics to attenuate cardiac inflammation.

VENTRICULAR TACHYCARDIA & VENTRICULAR FIBRILLATION

MO 1-04

ARTERIAL PH AND HEMOGLOBIN REGARDLESS OF AMIODARONE AND EMERGENT INTERVENTION ARE DETERMINANTS FOR SURVIVAL ON THE RETURN OF SPONTANEOUS CIRCULATION OF THE OUT-OF HOSPITAL CARDIAC ARREST

Ki-Woon Kang, Won Hyung Sung, Sang Won Seo, Yu Jeong Choi, San Hyun Park, Jung Yeon Chin, Won Ho Kim, Won Suk Lee, Jang Young Lee

Eulji University Hospital, Deajeon, Republic of Korea

Introduction: We investigated the comparison and association of clinical characteristics including medication and intervention betweer survival and non-survival on the return of spontaneous circulation (ROSC) of the Out-of Hospital Cardiac Arrest (OHCA) for 6 years.

Methods: Retrospective analysis of data from consecutive 229 OHCA occurring from 2010 to 2016 in which patients aged 19 years or older had an OHCA after arrival of emergency room, were treated in the Emergency Room and admitted into cardiology in Eulji University Hospital, Deajeon, Republic of Korea. All patients have undertaken emergent or elective coronary angiogram and echocardiogram to evaluate the cause of OHCA and divided into two groups; survival vs. non-survival.

Results: All consecutive 229 patients with ROSC were compared between survival (n=102) and non-survival (n = 127) who admitted to cardiac intensive care unit (ICU). The mean age of survival was younger than non-survival (60+16 vs. 70+15, p<0.001). However, the proportion of gender, hypertension and diabetes were similar between two groups. The proportion of ventricular tachycardia or fibrillation on the ECG before ROSC was significantly higher in the survival than non-survival (64% vs. 19%, p<0.001) while the proportion of amiodarone infusion was similar between two group (33.3% vs. 23.6%, p=0104). However, the etiology proportion of acute myocardial infarction confirmed by emergent intervention was similar between two groups (44% vs. 50%, p=0.345). In addition, the ejection fraction, hemoglobin and arterial pH were significantly higher in the survival than non-survival (43 + 16% vs. 23 + 27%, p<0.001; 13 + 2 g/dL vs. 12+2 g/dL, p<0.001; 7.1+0.1 vs. 7.0+0.1, p<0.001). Multivariate logistic regression showed that hemoglobin level and arterial pH were odd ratio 0.78 (0.67-0.90) with p=0.003 and 0.07 (0.01-0.40) with p=0.001. ROC analysis showed that hemoglobin >13 (sensitivity 75% and specificity 61%) and arterial pH >7.0 (sensitivity 62% and specificity 62%) were predictable for survival after ROSC.

Conclusions: Among the patients on the ROSC with OHCA, survival was significantly associated with hemoglobin and arterial pH among the characteristics and treatment including amiodarone and emergent intervention. Multicenter randomized prospective study was needed to confirm this result.

CARDIOVASCULAR IMPLANTABLE ELECTRONIC DEVICES

MO 1-05

PREDICTING THE DIFFICULTY OF A TRANSVENOUS LEAD EXTRACTION PROCEDURE : VALIDATION OF THE LED INDEX

Luca Bontempi1, Francesca Vassanelli1, Manuel Cerini1, Lorenza Inama1, Francesca Salghetti1, Nicolo Dasseni1, Clara Villa1, Daria Liberto2, Daniele Giacopelli3, Alessio Gargaro3, Abdallah Raweh4, Antonio Curnis1

Spedali Civili-University of Brescia, Brescia, Italy; University of Catania, Catania, Italy; 3Biotronik Italia, Milano, Italy; 4L.U.de.S. University Lugano, Switzerland

Introduction: The Lead Extraction Difficulty (LED) score was developed on a derivation sample to predict complex procedures of transve-nous lead extraction (TLE], LED> 10 criterion was estimated to be associated with a 78.3% sensitivity and 76.3% specificity. The aim of this study was to validate the LED index on an independent validation sample.

Methods: Consecutive patients undergoing TLE between January 2014 and January 2016 were included in this analysis. Procedures were classified as complex if the cumulative fluoroscopy time was >90th percentile at the end of the procedure. LED score is equal to the number of leads to be extracted + years from implant of the oldest target lead + 1 (if a dual-coil ICD lead must be removed]-! (if vegetation is confirmed along the lead body]. We tested whether LED ^10 predicts complex procedures.

Results: In total, 446 permanent leads (232 pacemaker, 143 ICD, and 71 sinus coronary leads] were removed during 233 TLE procedures. Complete procedural success was achieved in 232 (99.1%) patients with no major complications. The figure reports the complete set of classification probabilities of the LED index on this validation sample. Over the 23 cases with high fluoroscopy time, 20 had LED score>1C and were corrected classified. Only 3 procedures resulted false negative cases, leading to a 86.9% sensitivity and 98.0% negative predictive value.

Conclusions: The validation of the estimation model based on the LED index >10 confirmed a good sensitivity and an excellent negative predictive value proving reliable specially in detecting simple cases. The LED score may allow less experienced centres to more easily decide whether or not to refer to expert centres reducing overall patient risks.

LED >10 LED <10 Flu oro time >90* PCTL 20 (TP) Flu oro time <90th PCTL 63 (FP) 83

3 (FN) 23 147 (TN) 150 210 233

Sensitivity 86.9(66.4-97.2)%

Specificity 70.0(63.3-76,1)%

Positive predictive value 24.1(15.4-34.7)%

Negative predictive value 98.0 (94.3-99.6)%

Total accuracy 71.7(65.4-77.4)%

CARDIOVASCULAR IMPLANTABLE ELECTRONIC DEVICES

MO 1-06

RISK STRATIFICATION FOR SUDDEN CARDIAC DEATH IN JAPANESE HYPERTROPHIC CARDIOMYOPATHY PATIENTS WITH IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR

Miyo Nakano1, Yusuke Kondo2, Marehiko Ueda1, Masahiro Nakano1, Kazuo Miyazawa1, Tomohiko Hayashi1, Yoshio Kobayashi1

1Chiba University Graduate School of Medicine, Department of Cardiovascular Medicine, Chiba, Japan; 2Chiba University Graduate School of Medicine, Department of Advanced Cardiovascular Therapeutics, Chiba, Japan

Introduction: There are few reports about the clinical predictive factor which the appropriate implantable cardioverter defibrillator [ICD] therapies produces, and in regard to the adaptation of the ICD, there is a difference in Japan and European and American guidelines, anc it is the present conditions in that is controversial. The aim of this study is to assess the validity of risk stratification for indication of ICD ir Japanese patients with hypertrophic cardiomyopathy [HCM] by the 2014 ESC guideline. Hypothesis: The risk stratification for sudden cardiac death by the 2014 ESC guideline is valid in the Japanese patients with HCM.

Methods: We analyzed the characteristics of and outcomes for Japanese HCM patients with ICD. All patients were followed-up at our center.

Results: A total of consequence 51 HCM Japanese patients with ICD were enrolled in this study. All the patients meet class I or IIa in the guideline in Japan and the U.S. Over a mean follow-up period of 43±27 months, 7 patients [14%] received appropriate ICD therapies. The characteristics and outcomes of the patients were shown in the table and the figure, respectively. In patients with an ICD shock therapy during this follow up period, the 2014 ESC guideline would have recommended ICD implantation in 86% [6/7].

Conclusions: The risk stratification for sudden cardiac death by the 2014 ESC guideline seems to be valid in the Japanese patients with HCM.

Clinical characteristics

N n=51 Primary prevention (n-37) Secondary (n-11) P-value

Age G4±15 64+ 16 67 ±9.7 0.52

Sex, male (%) 84 92 81 0.52

CRT-D (%) 3.9 2.7 7.1 0.94

Follow-up priori (month) 43 ±27 44+26 40+28 0-67

LVEF(%) 61±13 62 ±11 60 ±17 0.70

LV maximum wall-lhickness(mm) 19 J. 5 20 ±5.2 18± 4.4 0.15

Cr(mg/dl) 0.9+0.3 0.89 ±0.2 1.0 ±0.4 0.14

Atrial fibrillation (%) 46 47 43 0.96

LAD (mm) 4618.5 4618.1 1819.7 0.37

family history 32 32 36 0.91

NSVI (%) 83 /8 /1 0.88

LOVT gradient (mmHg) 9.6±13 8.6 ± 10 12 ±18 0.47

Smoking rate (%) 63 68 50 0.42

UM(n) 2b (13) 30(11) 14(2) 0.44

Risk Stratification based JCS, AHA and ESC guidelines on Hypertrophic Cardiomyopathy (n=51)

Number of patients (JCS and AHA) Number of patients (ESC) experienced ICD therapies Percentage of appropriate ICD therapies

Class 1 14 -» 14 4 28%

Class IIa 37 ^ —* 7 2 29%

Class IIb 0 N io 1 10%

Class III 0 V 20 0 0%

BASIC/TRANSLATIONAL SCIENCE

MO 1-07

GENETIC POLYMORPHISM OF RYANODINE RECEPTOR 2 AND LEFT ATRIAL VOLTAGE IN PATIENTS WITH ATRIAL FIBRILLATION

Pil-Sung Yang, Ji-Young Lee, Tae-Hoon Kim, Jae-Sun Uhm, Boyoung Joung, Moon-Hyoung Lee, Hui-Nam Pak

Yonsei University Health System, Seoul, Republic of Korea

Introduction: Abnormal calaum release from sarcoplasmic reticulum [SR] is considered an important mechanism of atrial fibnllatior (AF]. Dysfunction of type-2 ryanodine receptor channels [RyR2] promote ectopic activity, conduction abnormalities, facilitating reentry, anc AF-related remodeling. Because decreased LA voltage is one of important markers reflecting atrial fibrosis, we investigated the association between genetic polymorphisms of RyR2 and left atrial (LA voltage among AF patients who underwent catheter ablation.

Methods: Mean LA voltage was obtained from individual LA voltage mapping in 469 patients (mean age 50.6+7.9 years, 82% male, 72% paroxysmal AF] who underwent AF catheter ablation. Total 292 single nucleotide polymorphisms in RyR2 were analyzed.

Results: In multivariate linear regression analysis adjusted by age, sex, and AF type, two single-nucleotide polymorphisms [SNPs] (rsl 337797, rs2490372] in RyR2 were independently associated with mean LA voltage after Bonferroni adjustment (rsl 337797: beta -0.182, 95% confidence interval [CI] -0.261 to -0.102, P=9.64x10-6, p=0.004 with Bonferroni adjustment; rs2490372: beta -0.164, 95% CI -0.243 to -0.083, p=7.13x 10-5, p=0.028 with Bonferroni adjustment]. In rs1337797, the heterozygous haplotype (n=221] demonstrated a 14% lower mean LA voltage (1.20 mV] and the homozygous risk allele carriers (n=73] demonstrated a 22% lower mean LA voltage (1.09 mV] compared with wild type (n= 175, 1.40 mV] (p=0.0004].

Conclusions: Two risk alleles in RyR2, rs1337797 and rs2490372, are independently associated with decreased mean LA voltage in AF patients. Our findings suggest that common genetic variations in RyR2 also related to atrial structural remodeling.

VENTRICULAR TACHYCARDIA & VENTRICULAR FIBRILLATION

MO 1-08

CATHETER ABLATION OF VENTRICULAR TACHYCARDIA IN ARRHYTHMOGENIC RIGHT VENTRICULAR CARDIOMYOPATHY-EXPERIENCE OF A TERTIARY CARE CENTER

Shibu Mathew, Ardan Saguner, Niklas Schenker, Andreas Metzner, Christine Lemes, Tilmann Maurer, Christan Heeger, Francesco Santoro, Karl-Heinz Kuck, Feifan Ouyang

Asklepios St. Georg, Hamburg, Germany

Introduction: Sustained Ventricular Tachycardia (VT] is common in patients with arryhthmogenic right ventricular cardiomyopathy (ARVC/ D], and associated with frequent ICD interventions, hospitalizations and reduced quality of life. Antiarryhtmic drugs are not always effective in suppressing ventricular arrhythmias and frequently associated with side effects. We assessed short term outcomes of radio frequency catheter ablation (RFA] for VT in a single -center cohort of patients with ARVC/D.

Methods: All RFA procedures addressing VT performed in our center between 1998 and 2015 in 40 patients (49.2±15.8 years; 83% male] with definite (n=32] or borderline (n=8] ARVC/D were analyzed. Procedural data and short-term success were determined.

Results: 71 RFA procedures using a three-dimensional mapping system were performed (mean 1.8 procedures/patient], of these 55% (n=39] using an endocardial approach, 34% (n=24] using a combined endo-epicardial approach, and 11% (n=8] using an epicardial approach. VT was inducible in 86% of patients referred for RFA of VT. In 44% of ablations >1 sustained VT was inducible and multiple VT morphologies (1.5± 1.0] were common (38%]. The mean cycle length of induced VT was 351 ±78 ms. Most VT had a LBBB morphology anc superior axis, correlating with the subtricuspid area as the most frequent VT exit site. Although fibro-fatty infiltration typically begins sub-epicardially an endocardial substrate with low voltage (bipolar <1.5 mV] and fragmented/late potentials was found in the majority patients (55%]. Procedural data are shown in the table. RFA was successful (defined as abolishment of all inducible VTs] in 86%, and partially successful (defined as abolishment of all clinical VTs] in 10%. 3 procedures on two different patients were not successful. The reason was the close proximity of the target substrate and ICD lead (combined endo-/epicardial approach] in the first case, and hemodynamically not tolerable VT in the second patient. VT ablation was generally safe with 1 (1.4%] pericardial tamponade occurring after epicardial puncture, and 9 minor complications (pericardial effusion n=2, mild pericarditis n=4, mild femoral hematoma n=3]. The majority of patients had an ICD (76%]. The number of sustained VT significantly decreased after RFA compared to before (27±38 vs. 4± 12, p<0.05]. The number of patients on anti arrhythmic drugs did not significantly change before and after RFA (93% vs. 90%, p=ns].

Conclusions: RFA is an effective strategy to reduce the sustained VT burden in patients with ARVC/D. Although the pathologic process begins in the subepicardium, the majority of patients referred for VT ablation has rather advanced disease stages, and thus presents with ar endocardial substrate amenable to endocardial RFA. Endocardial RFA has a high acute success rate, potentially obviating the need for a more invasive epicardial approach in some of these patients.

CARDIOVASCULAR IMPLANTABLE ELECTRONIC DEVICES

MO 1-09

TRANSVENOUS PACING USING CONVENTIONAL PACEMAKER IN PEDIATRIC PATIENTS <12 KGS : TECHNIQUE AND MIDTERM RESULTS

Vivek Pillai, Vidhyakar Balasubramaniam, Sivasankara Chakali, Jayaprakash Shenthar

Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bangalore, India

Introduction: Traditionally epicardial pacing systems have been routinely used for cardiac pacing in children weighing ^12 kg. Transve-nous pacemaker implantation in this subgroup presents unique challenges in terms of venous access, size of the veins, pacemaker pocket, and the hardware available. The disadvantages of smaller pulse generators available for children are, shorter battery life, and non-availability in many parts of the world. We describe a technique of transvenous lead implantation in children between ^12 kg using conventional adult pacemaker and leads.

Methods: This is an analysis of pediatric patients <12 kg who underwent permanent pacemaker implantation from January 2008 to May 2016 for standard Class I indication using a standard technique. All patients underwent PPI using a standard technique. An extra thoracic axillary vein puncture was performed using a 20-gauge needle, and wired using 0.025" guide wire. The 0.025" guide wire was exchanged for a 0.038" guide wire through a 4 F angiographic sheath. Sequential dilatation was performed using 5, 6 and 7 F dilators to introduce a 7F PLI. An active fixation 52 cms 6F lead was positioned in the RV, connected to the adult pulse generator. The pulse generator was placed in a subpectoral pocket.

Results: A total of 13 patients underwent PPI of whom 9 (62%) were males and 4 (38%) were females, mean age (2.46+0.8 years), mear body weight (9.69+1.45 kg). Indication for pacing was surgical AV block in 8 (61.6%) patients, and congenital AV block in 5 (38.4%). A single chamber VVIR pacemaker with a bipolar active fixation lead was implanted in all patients. Implant parameters were, mean R wave 11.19+ 4.54 (6.65 to 15.73) mV, mean impedance 652.46+136.6 (515.86 to 789.72) ohms, mean threshold 0.81+0.39 (.42 to 1.42) volts at 0.4 ms pulse width. The mean length of hospital stay was 5.3+ 0.63 (4.67 to 5.93) days. Over a follow up of 96 months a mean R wave 10.5+3.9 (6.6 to 14.4) mV, mean impedance 688.23 + 160.7 (527.53 to 848.93) ohms, threshold 0.98+0.36 (.62 to 1.34) volts at 0.4 ms pulse width was. There were no complications at implant and follow up.

Conclusions: Transvenous pacemaker implantation in children ^12 kg weight is feasible, safe, has short hospital stay with good medium term follow up results.

BASIC/TRANSLATIONAL SCIENCE

MO 1-10

EFFECT OF LOW-LEVEL ELECTRICAL STIMULATION OF THE AROTIC ROOT VENTRICULAR GANGLIONATED PLEXI ON STRUCTURAL REMODLING IN DOGS WITH HEART FAILURE

Hong-Tao Wang, Qiang-Sun Zheng

Tangdu Hospital, Xian, China

Introduction: Low-level electrical stimulation (LL-ES) of automomic nerve was reported to suppress atrial fibrillation (AF) by inhibiting the intrinsic cardiac autonomic nervous system and bring both anti- arrhythmia and anti-inflammation effect. However, it was still unknowr whether LL-ES could reverse the structural remodeling of myocardial fibrosis and atrial enlargement following heart failure (HF) Aim: This study was designed to investigate the anti-cardiac remodeling effect of LL-ES of the aortic root ventricular GP

Methods: Twenty dogs were randomly divided into control group and LL-ES group after rapid right ventricle pacing was performed to establish heart failure model. Following a week of LL-ES of the aortic root ventricular GP, bioactive factors for HF including angiotensin II, TGF-B,mitogen-activated protein kinase (MAPK), matrix metalloproteinase (MMP) was assessed. Furthermore, ventricle size, cardiac fii-brosis as well as left ventricular ejection fraction were also determined.

Results: Compared by control group, expression of angiotensin II, TGF-B, MAPK, and MMP were significantly down-regulated in LL-ES group (p<0.05). Moreover, the volume of left ventricle and cardiac fibrosis were markedly decreased, and LVEF in LL-ES group was significantly increased compared with those in control group (p<0.05).

Conclusions: Long term LL-ES of the aortic root ventricular GP improved rapid pacing induced cardiac structural and functional remodeling by attenuating the sympathetic tone.

CARDIOVASCULAR IMPLANTABLE ELECTRONIC DEVICES MO 1-11

SAFETY AND STABILITY OF PERMANENT HIS BUNDLE PACING

Weijian Huang1, Lan Su1, Shengjie Wu1, Lei Xu1, Zhenyu Dai1, Xiaohong Zhou2, Xiaohong Zhou2, Shungang Yang3

1The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China; 2CRHF Division, Medtronic, pic, Mounds View, United States; 3Medtronic Shanghai Innovation Center Shanghai, China

Introduction: Permanent His bundle pacing (HBP) has been pioneered recently while concern of HBP safety remains. This study assessec safety and feasibility of permanent HBP in heart failure patients with atrioventricular node (AVN) ablation for atrial fibrillation.

Methods: Fifty-two connective heart failure patients who received HBP and AVN ablation attempts were enrolled. In each patient, acute HBP was attempted in the AV septum superior to tricuspid valve with a Select Site sheath (C304 or C315) and the Select Secure 3830 pacing lead. Once HBP was achieved, AVN ablation was conducted. Success of AVN ablation produced a complete atrioventricular block without an injury to the HBP site and its distal part. Then, permanent HBP was applied with backup right ventricular pacing or bi-ventricular pacing. Follow-up was conducted to assess BHP.

Results: Acute HBP was achieved in 50 of 52 enrolled patients (96%), of whom, 42 patients (84%) received permanent HBP while remaining 8 patients (16%) did not receive permanent HBP due to His bundle injury by successful AVN ablation (N=2), incomplete AVN ablation (N=2) and later resumption of AV conduction following successful AVN ablation (N=4). After permanent HBP in 42 patients with follow-up of a median 20 months, there was no lead dislodgement; implant-related hospitalization occurred in two patients (1 for device replacement and 1 for minor device pocket infection); HBP threshold was stable with the percent change of 6.2 + 53.1% (median: 0%) in HBP thresholds at the last follow-up over baseline HBP thresholds (1.4+0.9 volts); and the percentage of HBP remained at 99.2+1.3%. After permanent HBP, LVEF increased to 60.1 +8.8% from the baseline 44.9 + 14.4% (p<0.001) and NYHA classification reduced to 1.4+0.5 from the baseline 2.8+0.6 (p<0.001). All 42 patients had at least one hospitalization for heart failure within one year prior to HBP while only 2 patients (4.8%) had heart failure-related hospitalization after HBP (p<0.001 vs. baseline).

Conclusions: Permanent HBP with backup right ventricular or bi-ventricular pacing is safe and stable with improved clinical outcomes ir a population of heart failure patients who underwent AVN ablation for atrial fibrillation.

MINI ORAL SESSION 02

PEDIATRIC/ADULT CONGENITAL HEART DISEASE

MO 2-01

BIATRIAL MACRRENTRANT ATRIAL TACHYCARDIA AFTER ABLATION AT BACHMANN'S BUNDLE IN PATIENTS WITH ATRIAL FIBRILLATION

Dae In Lee, Iqbal Mohammad, Kwang-No Lee, Seung Young Roh, Jinhee Ahn, Dong-Hyeok Kim, Jaemin Shim, Jong-Il Choi, Young-Hoon Kim

Korea University Anam Hospital, Seoul, Republic of Korea

Introduction: In patients with persistent atrial fibrillation (AF), extensive biatrial ablation is known to have better outcomes than left atrial (LA) ablation. Altered interatrial connections after biatrial ablation may provide an arrhythmogenic substrate for biatrial macro-reentrant atrial tachycardia (MRAT).

Methods: Patients with biatrial MRAT underwent a repeat procedure for recurrent atrial tachyarrhythmias after persistent AF ablation. All patients underwent extensive ablation at the LA, including at the Bachmann's bundle (BB).

Results: Two patients showed biatrial septal MRAT (tachycardia cycle length=270-330 ms); As shown in representative figure, the other 2 patients showed biatrial MRAT rotating along the right atrial free wall (tachycardia cycle length =410-470 ms). Electroanatomic mapping clarified the wavefront of biatrial MRAT propagating through the upper and lower interatrial connections. Ablation at the right atrial septum around the upper interatrial groove successfully terminated the biatrial MRAT (repsentative Figure C).

Conclusions: Extensive biatrial ablation at BB resulted in altered interatrial conduction, providing a substrate for biatrial MRAT. Ablation of the right atrial upper septum near the interatrial groove effectively terminated the biatrial MRAT.

CLINICAL ELECTROPHYSIOLOGY

MO 2-02

AGE CRITERIA MODIFICATION OF CURRENT RISK SCORES PREDICTING STROKE IN PATIENTS WITH ATRIAL FIBRILLATION: A NATIONWIDE COHORT STUDY IN KOREA

Daehoon Kim, PiL-Sung Yang, Tae-Hoon Kim, Jae-Sun Uhm, Hui-Nam Pak, Moon-Hyoung Lee, Boyoung Joung

Yonsei University College of Medicine, Seoul, Republic of Korea

Introduction: Recently, it was suggested that lowering the age threshold for stroke risk estimation help identify truly low stroke risk in Taiwan atrial fibrillation (AF) patients. This study hypothesized that lowering the cutoff age in current risk stratification scores (CHA2DS2-VASc, CHADS2, and R2CHADS2) might provide better stroke prediction.

Methods: We included non-valvular AF patients not using oral anticoagulants (OACs) from 506,805 adults in prospective cohort data collected by the National Health Insurance Service in Korea. The younger age groups of the current risk scores were divided into 2 subgroups by a cutoff of 55 years. We assigned -1 point to the younger subgroup (<55 years of age) and did not change the points assigned to other groups. The modified risk scores were compared with each original score by calculating the c-statistics and net reclassification improvement (NRI).

Results: During 14,430 person-years of follow-up, we observed 188 ischemic strokes. Annualized stroke rate was 1.3%. C-statistics for the full point scores improved after modifying the age criteria in all the risk scores (CHAeDS2-VASc: from 0.74 to 0.75; CHADS2: from 0.74 to 0.76; R2CHADS2: from 0.74 to 0.75). In the primary prevention subset (3,286 patients with no history of prior stroke), there were similar improvements of c-statistics (CHA2DS2-VASC from 0.68 to 0.70; CHADS2: from 0.67 to 0.70; R2CHADS2: from 0.67 to 0.70). The NRIs were positive comparing the modified score with each original score (CHA2DS2-VASC 27.1%; CHADS2: 4.7%; R2CHADS2: 2.2%).

Conclusions: By using the lowered cutoff age (55 years of age), refining the age criteria of current risk scores provided improved stroke prediction in atrial fibrillation patients.

Table. C-index values and NRI for current risk schemes before and after modification of age criteria

C-index (95% confidence interval)

Risk stratification scheme

CHA2DS2-VASc

Full cohort (n=3,932) Before After

Modification 0.71 0.75

(0.70 to 0.77) (0.71 to 0.78)

Primary prevention cohort (n=3,286) Before After

Modification 0.68 0.70

(0.63 to 0.73) (0.65 to 0.75)

cohort p* (n=3,932)

CHADS?

0.74 0.76

(0.71 to 0.78) (0.73 to 0.79)

0.67 0.70

<0.01 <0.01 (0.62 to 0.73) (0.66 to 0.75)

R2CHADS2

0.74 0.75

(0.70 to 0.78) (0.72 to 0.79) * The /rvalues refer to the Delong test for differences in ROC prediction.

0.67 0.70

0.01 <0.01 (0.62 to 0.73) (0.65 to 0.75)

* Positive NRI values indicate improvement by modification, compared with original scores.

CLINICAL ELECTROPHYSIOLOGY

MO 2-03

IMPACT OF ATRIAL FIBRILLATION ON OUTCOMES AFTER EMERGENCY CHEST PAIN PRESENTATION

Daniel Lancini1, Paul Martin1, Louise Cullen1, Jaimi Greenslade1, Christopher Hammett1, Sandhir Prasad1, Martin Than2, William Parsonage1

Royal Brisbane and Women's Hospital, Brisbane, Australia; 2Christchurch Hospital, Christchurch, New Zealand

Introduction: Atrial fibrillation (AF) has been associated with increased mortality in patients admitted with acute coronary syndrome (ACS). However, the impact of AF on mortality in undifferentiated emergency chest pain presentations is unclear

Methods: This study prospectively collected data on 983 patients presenting with suspected ACS to a tertiary emergency department (ED) in Australia. Patients were followed to 1 year for mortality.

Results: 91 out of 983 patients had a history of AF (see Table 1), which was associated with older age, and higher rates of comorbidities including hypertension, dyslipidaemia, heart failure, coronary artery disease and stroke/TIA. A history of AF was also associated with increased mortality at 1 year (9.1% vs. 2.1%), however this association was not significant on multivariate analysis.

Conclusions: Amongst undifferentiated emergency chest pain presentations, patients with previous AF are at increased risk for 1 year mortality. However, it is unclear whether this is attributable to AF or associated confounders including age and cardiovascular comorbidities. As a modifiable condition, AF may represent a possible therapeutic target to reduce mortality in this high-risk population.

Characteristics No Atrial Fibrillation Previous Atrial Fibrillation p-value

(n=892) (n=91)

Demographics

Male gender 540 (60.5%) 58 (63.7%) 0.55

Mean age 53.65 (14.65] 67.49 (14.00) <0.001

Comorbidities

Hypertension 352 (39.5) 66 (72.5) <0.001

Diabetes 106 (11.9) 15 (16.5) 0.203

Dysii]3idaemia 361 (40.5) 56 (61,5) <0.001

Smoker 258 (28.9) 16 (17.6) 0.022

Heart failure 30 (3.4%) 17 (18.7%) <0.001

Previous MI 139 (15.6%) 31 (34.1%) <0.001

Previous stroke/TIA 69 (7.7%) 18 (19.8%) <0.001

Coronary artery disease 159 (17.8%) 46 (50.5%) <0.001

Survival

Admission 891 (99.9%) 90 (98.9%) 0.047

30 days 889 (99.7%) 90 (98.9%) 0.276

1 year 659 (97.9%) 60 (90.9%) <0.001

Table 1: Patient demographics, comorbidities and survival outcomes. Data are n[%) or meanfstandard deviation]. Note: for 1 year mortality, n=672 for no AF and n=66 for previous AF.

CLINICAL ELECTROPHYSIOLOGY

MO 2-04

FREQUENT ACCELERATED VENTRICULAR RHYTHM

Hailei Liu, Minglong Chen

The First Affliated Hospital of Nanjing Medical University Nanjing, China

Introduction: This observational study aims to describe the clinical manifestation, diagnostic criterion and management of a cohort of patients with frequent accelerated ventricular rhythm (FAVR) and to investigate the underlying electrophysiological mechanism of FAVR as well as its impact on the prognosis.

Methods: 20 patients (15 males) suspected with FAVR were consecutively enrolled in our study. ECG, 24-hour Holter monitoring anc transthoracic echocardiogram were performed during hospitalization. Drug sensitivity test, treadmill test, electrophysiological study and catheter ablation would be applied after informed consent obtained. The patients were followed 5 months to 12 years after discharge.

Results: The average age of the patients was 31.8 ± 14.7 years. None of them were accompanied with structural heart disease except that two of them were diagnosed with dilated cardiomyopathy and mirror-image dextrocardia, respectively. FAVR was exhibited on the surface ECG and 24-hour Holter at admission. There was significant differences between FAVR arising from working ventricular myocytes and His-Purkinje system in terms of QRS complex duration (175+17.7 ms vs. 118.2+11.6 ms, p<0.001). There were significant negative correlations between left ventricular ejection fraction (LVEF) and FAVR burden (2-tailed, R2=0.66, p<0.01), as well as LVEF and average heart rate (2-tailed, R2=0.45, p<0.05). FAVR would be easily accelerated during isoproterenol intravenous administration and treadmill test. But when the heart rate climbed over 130 bpm, sinus rhythm would be dominant on the surface ECG. A centrifugal pattern was exhibited during electrophysiological study. Sensitive drugs were diverse from each other, whereas metoprolol could be chosen if the drug sensitivity test was not accepted by the patients because most of FAVRs were sensitive to it (87.5%, 7/8). During follow-up period, two of them deceased (case 3, case 9). Most of the patients with impaired LVEF got complete recovery (5/6). Nevertheless, one of them only got partial recovery. The rest had no discomfort complaints and got FAVR burden reduced.

Conclusions: Palpitation and symptoms associated with heart failure are considered to be the major discomforts for patients with FAVR. Although most of them are free of structural heart disease, but the FAVR itself has the possibility to impact LVEF. FAVR could be well controlled by catheter ablation and sensitive drug administration. Catheter ablation should be considered as first-line therapy for patients with high risks. Enhancement of focal automaticity and imbalance of autonomic nervous system are suspected to be the electrophysiological mechanisms of FAVR.

CLINICAL ELECTROPHYSIOLOGY

MO 2-05

ABORTED SUDDEN CARDIAC DEATH OR SYNCOPE DUE TO LIFE THREATENING VENTRICULAR TACHYARRHYTHMIA IN YOUNG KOREAN SOLDIERS

Hee Sun Mun1, Jung Myung Lee2, Kyung Ho Kim1, Jinyoung Park1, Sung Soon Kim1

'Korean Armed Forces Capital Hospital, Seongnam, Republic of Korea; 2Kyung Hee University, Seoul, Republic of Korea

Introduction: Sudden cardiac death (SCD) among military recruits is rare but devastating. The underlying causes of SCD in young soldiers have not been studied in Korea.

Methods: We reviewed 21 patients (mean age of 21 years, 20 males) who were referred for the evaluation and management of abortec SCD or syncope due to life threatening ventricular tachycardia (VT) from 2012 to 2015.

Results: The underlying heart diseases and treatment modalities were summarized in Figure. Ventricular fibrillation (VF) was documented on automated external defibrillator (AED) in 16 patients. Among them, 13 patients received implantable cardioverter-defibrillator (ICD). Two patients with Wolff-Parkinson-White syndrome underwent radiofrequency catheter ablation for accessary pathway. One with coronary artery spasm was treated with medications. Four patients with long QT syndrome and syncope due to nonsustained fast polymorphic VT were found to have genetic mutation (KCNH2) and managed with beta blocker. In one soldier with asymptomatic Brugada syndrome, ICD was implanted for primary prevention because he was a sibling of the soldier proband, and also had SCN5A mutation with easily inducible fast polymorphic VT degenerating to VF during electrophysiology study

Conclusions: Most life threatening ventricular tachyarrhythmias were caused by electrical heart diseases. Channelopathies accouted for nearly half of them. Therefore, an initial approach in this population should be focused on evaluation for the electrical heart disease. Above all, basic life support training and AED disposition should be emphasized for the successful resuscitation of SCD in young healthy sol-

ALLIED PROFESSIONALS MO 2-06

CARDIAC SYMPATHETIC DENERVATION AFTER FAILED RADIOFREQUENCY ABLATION

Ilknur Can1, Jian Ming Li2, Rosemary F Kelly3, Venkatakrishna Tholakanahalli2

1Necmettin Erbakan University, Konya, Turkey; 2Univers'ity of Minnesota VA Medical Center Cardiology, Minneapolis, United States; University of Minnesota VA Medical Center Cardiothoracic Surgery Minneapolis, United States

Introduction: The sympathetic nervous system has long been associated with the genesis and maintenance of many life threatening ventricular arrhythmias. The standard of care in patients with ventricular tachycardia storm representing a clinical situation of acute electrical stability has long been antiarrhythmic therapies and catheter ablation. In this case series we have presented five patients who underwent cardiac sympathetic denervation as a last resort to treat their recurring ventricular arrhythmias.

Methods: All patients (Table) presented with several episodes of ventricular tachycardia (VT) refractory to medical therapy. All the patients (except case 4 which was not performed due to proximity of foci to the coronary artery) underwent endocardial and/or epicardial radiofrequency catheter ablation procedure which failed to prevent recurrences. As a next step, video assisted thoracoscope sympathectomy procedure was performed under general anesthesia from the lower half of stellate ganglion to T4.

Results: During the follow-up all patients were free of VT episodes. Patient 1 received a heart transplant after one year. Patient 3 who hac the sympathectomy procedure after surgical replacement of mitral valve did not experience further VT episodes but died of sepsis in the hospital after 2 months. Patient 4 did not have further VTs but was found to have similar premature ventricular contractions with up tc 40% burden. Two of our patients underwent bilateral cardiac sympathetic denervation (case 5 had prior left sympathectomy), however the other patients were not amenable for bilateral denervation. Though it is still a debate to remove unilateral or bilateral portion of the sympathetic chain (lower half of stellate ganglion and T2-T4), bilateral CSD is the preferred procedure in our center whenever possible from surgical standpoint.

Conclusions: The presented case series, despite disparate causes responded to cardiac sympathetic denervation in all of the patients without any further clinical VTs. Cardiac sympathectomy is an emerging effective alternative therapy for those patients who deemed unresponsive to standard treatment with medical therapy and catheter ablation.

Patient Age-sex Heart disease EF (%) ICD VT ablation Sympathectomy Follow-up (months) Recurrence

1 64 M NICM 20 + Ende Bilateral 12 None

2 66 M ICM 45 + Endo+Epi Left 24 None

3 73 M MVR 40 Ende Left 2 Died (sepsis)

4 42 M Idiopathic 55 Bilateral 24 No VT, but PVCs

5 61 M NICM 40 + Endo+Epi Right 1 None

PEDIATRIC/ADULT CONGENITAL HEART DISEASE

MO 2-07

THE EFFICACY OF FREEZER MAX TO MITRAL ISTHMUS ABLATION: THREE CASE REPORTS

Kenji Kuroki, Akihiko Nogami, Tomoaki Hasegawa, Fumi Yamagami, Yasutoshi Shinoda, Satoshi Aita, Eiko Sai, Ai Hattori, Toru Adachi, Yuki Komatsu, Keita Masuda, Takeshi Machino, Hiro Yamasaki, Yukio Sekiguchi, Nobuyuki Murakoshi, Keisuke Kuga, Kazutaka Aonuma

University of Tsukuba, Tsukuba, Japan

Introduction: It is sometimes difficult to complete the block line at mitral isthmus because of instability of ablation catheter Methods: N/A.

Results: The 1st case is 70-year-old man with atrial tachycardia (AT). He developed AT during a follow-up period after pulmonary vein isolation (PVI). Although mitral flutter was induced in the 2nd session, but a complete block line could not be achieved. In the 3rd session, after ablation with cryoballoon to Left pulmonary vein, mitral flutter (MF) was induced. MF was terminated by 6th cryoenergy delivery with Freezer max (FM) to mitral isthmus (Figure). The 2nd case is a 39-year-old male with Atrial fibrillation (AF) and AT. After PVI with cryoballoon, MF was induced. MF was terminated by 3rd cryoenergy delivery with FM. The 3rd case is a 73-year-old male with AF. During PVI with cryoballoon, AF appeared spontaneously and changed to MF. After PVI was completed with cryoballoon, MF was terminated by 2nc cryoenergy delivery with FM to mitral isthmus. A total of 9, 4, 8 times of cryoenergy per each patient was delivered and a bidirectional block was completed in all patients. During the mean follow-up of 223 days, no AF or AT did not recur in all patients.

Conclusions: Freezer Max can be a powerful tool to complete a block line at mitral isthmus due to its property of freezing and sticking onto atrial muscle.

CLINICAL ELECTROPHYSIOLOGY

MO 2-08

NON-FATAL MYOCARDIAL INJURIES AMONG MARATHON RUNNERS-A 15-YEARS EXPERIENCE OF HONG KONG STANDARD CHARTERED MARATHON

Kit Chan1, Kuang An Wan1, Sai Chau Leung1, Ngai Shing Mok2, Natalie Leung3, Jessica, Wai Ling Poon1, Yuk Kong Lau1

Ruttonjee and Tang Shiu Kin Hospitals, Wan Chai, Hong Kong; 2Princess Margaret Hospital, Lai Chi Kok, Hong Kong; Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong

Introduction: Over the past 15 years (2002-2016), 750,960 people participated in the Hong Kong Standard Chartered Marathon, which is one of the largest marathon event in Asian Pacific Region. We aim to study the prevalence of non-fatal myocardial injury among the marathon runners.

Methods: All the Standard Chartered Marathon related hospital admissions over the past 15 years (2002-2016) were retrieved from Accident and Emergency Department admission record. We reviewed the prevalence, epidemiological profile and clinical outcome of marathon runners admitted for non-fatal myocardial injury.

Results: The past 15 years, among the 750,960 marathon participants, there were 33 runners admitted for non-fatal myocardial injury (Mean age 41.8 ± 12 years old. 28 Males. Eleven 10 km runners, 12 half-marathon runners and 8 full marathon runner. Race distance was unknown in 2 runners). Among the 33 runners, only 5 (15.2%) complained of chest pain. Twenty-one (63.6%) developed syncope. ST-seg-ment changes greater than 1 mm were observed in 12 (36%) patients. One patient had Wolff-Parkinson-White Syndrome and receivec successful radiofrequency ablation of accessory pathway. One patient developed atrial fibrillation. The mean left ventricular ejection fraction was 58 ±4%. Four patients underwent exercise treadmill tests, which were all negative for ischemia. Coronary angiograms were performed in 8 (24%) patients, revealing mild coronary artery disease, single vessel disease and triple vessels disease in 3, 1 and 4 patients respectively. Computed tomography coronary angiogram done in 2 (6%) patients revealed normal coronary arteries. Angiogram was not performed in 70% of patients because of low pre-test likelihood of coronary artery disease. Percutaneous coronary angioplasty and coronary artery bypass surgery were performed in 3 and 2 patients respectively.

Conclusions: The prevalence of non-fatal myocardial injury among Standard Chartered Marathon runners was 4.4 per 100,000 (33 patients) over past 15 years. Syncope and chest pain occurred in 63.6% and 15.2% of patients respectively. Significant ST segment changes occurred in only 1/3 of patients. Coronary artery intervention was required only in a minority of patients.

PEDIATRIC/ADULT CONGENITAL HEART DISEASE

MO 2-09

INCESSANT LEFT VENTRICULAR TACHYCARDIA OF UNUSUAL ETIOLOGY

Praloy Chakraborty1, H S Isser1, Sudheer Arava2, Kausik Mandal3

!VMMC and Safdarjung Hospital, Delhi, India; All India Institute of Medical Science, Delhi, India; 3Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India

Introduction: Usual causes of left ventricular tachycardia include coronary artery disease, cardiac sarcoidosis, left ventricular tumor; cha-gas disease and idiopathic left ventricular tachycardia.

Methods: N/A.

Results: A 40 years male patient presented with incessant left ventricular tachycardia which was controlled with combination of antiarrhythmic therapy. Contrast enhanced cardiac MRI showed abnormal sub-endocardial and mural late gadolinium enhancement within apical inferior and apical septal wall of left ventricle. CECT chest, cardiac PET-CT and coronary angiography were normal. Mantoux test was positive and The QuantiFERON-TB Gold test (QFT-G) was within normal range. Endomyocardial biopsy showed myocyte loss and fatty replacement. A diagnosis of left dominant arrhythmogenic cardiomyopathy (LDAC) was made. Genetic analysis using Next Generation sequencing technique and targeting genes associated with arrhythmogenic cardiomyopathy showed that individual harboured a variation (p.Thr277Ser) caused by a substitution (c.829A>T) in exon 10 of the TMEM43 gene. His mother did not have this variation by mutation analysis study and father was not available for gene testing. Although concurrent left ventricular involvement along with right ventricle occurs in 75% cases of advanced arrhythmogenic right cardiomyopathy (ARVC), isolated LV involvement is rare. In a study of 200 patients 5% patients had isolated left ventricular involvement. About 75% of LDAC present with ventricular arrhythmia from left ventricle. TMEM43 is a highly conserved inner nuclear membrane (INM) protein. Mutation of TMEM43 may cause arrhythmogenic cardiomyopathy by altering the structure and function of desmosomal proteins. Significance of p.Thr277Ser substitution is unclear. Till date this variation is considered as variant of unknown significance (VUS).

Conclusions: we report a case of incessant left ventricular tachycardia due to unusual form of arrhythmogenic cardiomyopathy (LDAC) associated with variation in TMEM43 gene.

PEDIATRIC/ADULT CONGENITAL HEART DISEASE

MO 2-10

CATHETER ABLATION FOR A VENTRICULAR PREMATURE CONTRACTION TRIGGER REFRACTORY ELECTRICAL STORM AND VENTRICULAR FIBRILLATION

Weichieh Lee, Huang-Chung Chen, Yung-Lung Chen, Mien-Cheng Chen

Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan

Introduction: Electrical storm is a life-threatening medical emergency and a challenging problem for physician. Refractory electrical storm could happen even through high arrhythmic medical control and deep sedation and mechanical support. We introduce a case about catheter ablation of ventricular premature contraction triggered ventricular fibrillation under extracorporeal membrane oxygenation and intra-aortic balloon pumping support.

Methods: Catheter ablation was performed under ensite 3D mapping system under ECMO and IABP and ventilator support. Clinical VPC showed left axis deviation and right bundle branch block, which was suspected left ventricular origin. One 4 Fr. decapolar catheter were introduced percutaneously into the right femoral vein, which was positioned in the right atrium with cross tricuspid valve, and the tip was in the apex of right ventricle. Geometry creation and voltage mapping (setting 0.2-0.8 mV) were performed with the 7 Fr quadripolar irrigation ablation catheter. Posterior view of voltage map presented left posterior fasicular site at border zone. Right anterior oblique view of voltage map presented large scar area at inferior and anteroseptal site. The ablation catheter detect the Purkinje-like potential at border zone. During ablation over left posterior fascicular site, VF and short-run ventricular tachycardia were induced. The morphology of VT was similar to clinical VPC. Pacing mapping also showed 12/12 matching. Raiofrequency energy 50 Watts (at target of 48 Celcius) for 30 secs at each points was appiled from inferior posterioseptal (fascicular site) to anterioseptal border zone region. Substrate modification of the border zone was performed ablation till no Purkinje potentials with voltage less than 0.1 mV. No more VT/VF could be induced till triple extrastimuli pacing (right ventricular pacing: 400/280/270/260 ms) under control. A total ablation area was 6.1 cm2.

Results: ICD record did not detect any episode of ventricular arrhythmia at three-month follow-up period.

Conclusions: Catheter ablation is an efficacy method to deal with electrical storm even if ECMO and IABP use.

PEDIATRIC/ADULT CONGENITAL HEART DISEASE

MO 2-11

FLUOROSCOPY IMAGE INTEGRATED 3D MAPPING SYSTEM REDUCES RADIATION EXPOSURE DURING ABLATION FOR PEDIATRIC CARDIAC ARRHYTHMIAS

Yoko Yoshida1, Shigeo Watanabe1, Shuichiro Yoshida1, Tsugutoshi Suauki1, Yoshihide Nakamura2

1Osaka City General Hospital, Osaka, Japan; Kinki University, Osaka, Japan

Introduction: Risks with exposure to radiation especially in young patients undergoing electrophysiology procedures and medical staff engaged in are a serious concern. We studied whether the use of a novel fluoroscopy image integrated 3-dimensional electroanatomical mapping system (CARTO3 with UNIVU module) could reduce radiation exposure during ablation for various pediatric arrhythmias.

Methods: This study was a retrospective, single-centere study. The primary endpoints of this study was the change of fluoroscopy time and fluoroscopy dose using flouroscopy integreted 3D mapping (UNIVU) compared with the conventional 3D mapping system (CARTO3). Eligible subjects were consecutive patients <20 years of age who performed radiofrequency catheter ablation for various arrhythmias using CARTO3 system. In the first 4 months before UNIVU became available in our hospital on October 2015, the control group used conventional CARTO3 system was enrolled. In the following 4 months UNIVU group was enrolled. Results of categorical variables are expressed as number and percentage of patients. Statistical analyses of categorical variables were done using Pearson's chi-square test. Continuous variables are expressed as median and IQR. Statistical analyses were done using Wilcoxon signed-rank test. Significance level was set at P< 0.05.

Results: In this retrospective study, in total 46 consecutive patients were included (UNIVU group: N=18, CARTO3 group: N=28). The age, body weight and the incidence of patients with congenital heart disease did not differ between the two groups: 10.1 (7.2-14.0) years vs. 11.1 (7.28-14.6) years (P=0.761); 31.3 (20.5-43.1) kg vs. 35.6 (19.8-28.8) kg (P=0.919); 4 (22.2%) vs. 7.1% (P=0.138). The target arrhythmias of the two groups were: WPW syndrome (11 vs. 17), ventricular arrhythmias originated from outflow (2 vs. 6), others (5 vs. 5). The incidence of procedures using retrograde approach and using trans-septal puncture were not differ between the two groups: 1(8.7%) vs. 3 (10.7%) (P=0.545); 5 (27.8%) vs. 8 (28.6%) (P=0.954). Four different operators performed ablation procedures. The median years of experience of operators was shorter in UNIVU group than CARTO3 group: 0.67 (0.58-0.57) years vs. 12.2 (4.17-12.3) years. In total, the UNIVU allowed a reduction in fluoroscopy time: 2.6 (0.38-5.22) minutes vs. 18.4 (14.7-27.8) minutes (P<0.001), and fluoroscopy dose (Air Kirm): 17.5 (6.0035.8) mGy vs. 78.5 (33.5-307) mGy (P< 0.001). The number of ablation points, procedure time, acute success rate and incidence of adverse events did not differ.

Conclusions: The image integrated 3-dimensional electroanatomical mapping system contributed to significant reduction of radiation exposure to pediatric patients and staff during electrophysiological procedures.

CLINICAL ELECTROPHYSIOLOGY

MO 2-12

THE IMPACT OF FASCICULOVENTRICULAR BYPASS TRACTS ON THE DIAGNOSIS AND TREATMENT OF CONCOMITANT ARRHYTHMIA AND CARDIAC DISEASE

Yong-Giun Kim1, Gi-Byoung Nam2, Jun Kim2, Kee-Joon Choi2, You-Ho Kim2

1 Ulsan University Hospital, Ulsan, Republic of Korea; Asan Medical Center Seoul, Republic of Korea

Introduction: Fasciculoventricular (FV) bypass tracts are the rarest form of ventricular preexcitation and none of them are involved in clinically significant reentrant tachycardia. However they may cause diagnostic confusion if not properly understood.

Methods: Ten patients with FV bypass tracts who underwent electrophysiologic studies were evaluated. The proof of FV bypass tracts relied on 1) normal AH interval and short HV interval, 2) demonstration of fixed preexcitation with decremental atrioventricular (AV) node conduction and 3) preexcitation during a His extrasystole.

Results: One patient had a FV bypass tract with complete infra-hisian AV block which mimicked slow ventricular escape rhythm. Two patients had a FV bypass tract with atrial fibrillation (AF) or atrial flutter (AFL), which was misinterpreted as AV bypass tract requiring emergency DC cardioversion. Five patients had accompanying AV bypass tracts (right lateral AV bypass tracts in two patients, right posterosep-tal AV bypass tracts in two patients, and a left lateral AV bypass tract in one patient). Among those, three AV bypass tracts participated in AV reentrant tachycardias, while two AV bypass tracts showed short ERP producing rapid ventricular response during induced AF or AFL. In two patients with AV bypass tracts, unnecessary RF application was delivered after successful ablation of the AV bypass tracts because conduction through FV bypass tract was mistaken for conduction through residual AV bypass tract (Table 1). Two patients had no concomitant arrhythmia, however one of them is a hypertrophic cardiomyopathy patient who should take an AV nodal blocker. FV bypass tract mimicked the AV bypass tract and patient had not taken the AV nodal blocker before electrophysiologic study.

Conclusions: FV bypass tracts were frequently accompanied by AV bypass tracts or other arrhythmias and cardiac disease. They may cause diagnostic confusion and even unnecessary RF delivery when misinterpreted as AV bypass tracts.

Table 1. Characteristics of concomitant arrhythmia and cardiac disease of FV bypass tracts.

PtNo. AVRT Other arrhythmia/ cardiac disease Treatment

1 (-) Complete AV block PPM implantation

2 (-) Spontaeuous AF* PV isolation

3 (-) Spontaeuous AFL* CTI ablation

4 (+) using Rt' lateral AV bypass tract ablation

5 (+) using Rt' lateral AV bypass tract ablation§

6 (-) Rt' PS with short ERP Induced AF/ Ebstein's anomaly AV bypass tract ablation

7 (-) Rt' PS with short ERP Induced AFL AV bypass tract ablation

8 (+) using Lf lateral AV bypass tract ablation§

10 (-) HCMP

♦Unnecessary cardioversion.

MINI ORAL SESSION 03

ELECTROCARDIOGRAPHIC ELECTROPHYSIOLOGICAL FEATURES OF EPICARDIAL ACCESSORY PATHWAYS ABLATED WITHIN THE MIDDLE CARDIAC VEIN

Balasubramanian Vidhyakar, Pillai Vivek, Sivasankara Chikalli, Shenthar Jayaprakash

Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bangalore, India

Introduction: Some posteroseptal accessory pathways have an epicardial course within the middle cardiac vein (MCV) and require ablation within the MCV. Failure to recognize this is one of the causes of unsuccessful ablation. The electrocardiographic, electrophysiologic features of manifest posteroseptal pathways requiring ablation within middle cardiac vein (MCV) have not been well described.

Methods: All patients who underwent ablation of manifest posteroseptal accessory pathway from 2008 to May 2016 were included in the study All patients underwent coronary sinus venogram during the study. Patients who had coronary sinus diverticulum on venogram were excluded from the analysis and the rest were classified as Group I (pathway ablated within the MCV), and group II (pathway ablated in the posteroseptal region). The clinical, electrocardiographic, and electrophysiological, features were analysed retrospectively.

Results: There were 168 patients with mean age of 38±13 years (12-68 years), of whom 98 were males and 70 females. Twenty eight patients had coronary sinus diverticulum and were excluded from the study. Of the remaining 140, there were 26 (18.6%) patients in Group I (MCV) and 114 (81.4%) Group II. The ECG feature suggestive of Group I were, QS in lead III with notching of the descending limb of S wave (sensitivity 74%, specificity 90%), positive delta wave in lead aVR (sensitivity 73%, specificity 90%), negative delta wave in lead II (sensitivity 72%, specificity 89%), deep S in V6 (sensitivity 63%, specificity 88%). The local VA time on IEGM was longer in Group I compared to Group II (90±20 ms vs. 74±15 ms [P=0.001]). A discrete potential was seen near the ostium of MCV at the site of successful ablation.

Conclusions: The posteroseptal accessory pathways requiring ablation inside the MCV specific features. They are a) QS in lead III with notching of descending limb of S wave, b) negative delta in lead II, c) positive delta wave in lead aVR, and d) a deep S wave in lead V6. The presence of these findings are useful for anticipating and planning the ablation strategy

MECHANISTIC PROOF THAT HUMAN AF CAN BE DRIVEN BY ATRIAL TACHYCARDIAS OUTSIDE THE PULMONARY VEINS

Christopher Kowalewski1, Junaid A. B. Zaman1, Ryan T. Borne2, Tina Baykaner1, Shirley Park1, Mohan Viswanathan1, Paul J. Wang1, David Krummen3, William H. Sauer2, Sanjiv M. Narayan1

'Stanford University, Palo Alto, United States; 2UC Denver, Aurora, United States; \A Medical Center, San Diego, United States

Introduction: AF can be initiated by triggers near pulmonary veins (PV), yet it is unproven if AF can actually be sustained by focal atrial tachycardias (sources) in the atria. We hypothesized that panoramic mapping may reveal organized AF sources which meet classical mechanistic criteria for organized tachycardia.

Methods: We performed basket mapping of AF ablation at 3 centers. We selected cases in whom AF terminated abruptly by ablation at localized sources, defined as centrifugal activation from an origin during AF, with electrograms on global atrial mapping spanned <50% of AF cycle length.

Results: Sixteen patients (age 64.6±8.4 years, LA vol. index 2.1 ±0.1 mL/m2, LVEF 55.3±6.3%) met a priori criteria for focal AF sources. Figure A shows AF in a 56 year old woman, in whom 4 sequential maps (B) showed repetitive anisotropic centrifugal activation from an origin, (C) with electrograms spanning <50% AF CL (blue arrow). This AF-driving focal tachycardia lay within a 2-3 cm2 area. Targeted ablation terminated AF to sinus rhythm. Neither AF nor AT were inducible afterwards. In both the left and right atria 75% of Focal drivers lay in the atria and away from the PVs.

Conclusions: This study demonstrates that focal atrial tachycardias away from the PVs may sustain human persistent AF, meeting classical mechanistic criteria for focal sources and producing fibrillatory conduction, where targeted ablation eliminated AF. Future studies should determine how focal sources relate to rotational circuits and their relationship to AF triggers.

MO 3-03

OPTIMIZING CRT WITH NEGATIVE HYSTERESIS AND LV PRE-EXCITATION

David O'Donnell1,2, Taylah Smart2, Juliette Young1, Ryan Spencer1, Hui Chen Han1, Lisa Odgers3, Tina Lin1,2

'Austin Hospital, Melbourne, Australia; 22Genesis Care, Melbourne, Australia; 3St. Jude Medical, Melbourne, Australia

Introduction: Right ventricular (RV) synchronized left ventricular (LV) pacing has been shown to reduce QRSd and enhance some of the effects of cardiac resynchronisation therapy (CRT). Additionally an R wave in V1 on the surface ECG is useful for guiding programming and predicting response to CRT Utilizing a device based Negative Hysteresis (NH) algorithm, this study compared the ECG effects of increasing NH delays with increasing LV pre-excitation in chronically implanted CRT patients.

Methods:

Consecutive patients implanted with a SJM quadnpolar lead and SJM device were screened. Those patients with PR interval <350 ms were enrolled. All RV leads were midseptal with a Q-RV duration <15 ms (mean 7.4+6 ms), the LV lead had a mean Q-LV duration of 134 + 21 ms and QLV% of 87%+7. 12 lead ECGs were performed in intrinsic rhythm and in best biventricular pacing mode (BiV). NH was performed with NH delays from -10 to -80 ms, and with both simultaneous RV and LV activation (Sim) and with LV 40 ms ahead of RV (LV+40 ms). The QRSd was recorded. The relative contribution of R wave vector in V1 was measured as % of total QRS vector in V1.

Results: 17 patients were evaluated, the mean QRSd was reduced with the best NH mode (130.7±17 ms) compared to the best BiV mode (150± 15 ms). A NH between -10 and -50ms resulted in the lowest QRSd in 90% of patients. The QRSd did not change significantly between Sim (130.7±17 ms) and LV+40 (133.4±18 ms). Relative contribution of R wave vector in V1 was significantly greater in LV+40 (34± 21%) compared to Sim mode (15 ± 11%).

Conclusions: The NH algorithm can reduce QRSd compared with best BiV settings. Manipulation of LV pre-excitation can increase the R wave in V1 suggesting increased LV contribution to the ECG without prolonging QRSd.

MO 3-04

COMPARISON OF DE-NOVO vs. UPGRADE CARDIAC RESYNCHRONIZATION THERAPY; FOCUSED ON THE UPGRADE FOR PACING-INDUCED CARDIOMYOPATHY

Hye Bin Gwag, Jin Kyoung Hwang, Kyoung-Min Park, Young Keun On, June Soo Kim, Seung-Jung Park

Samsung Medical Center, Seoul, Republic of Korea

Introduction: It remains unclear whether the upgrade cardiac resynchronization therapy (CRT) would show better outcomes than the de-novo CRT We compared the efficacy of CRT between the de-novo and upgrade groups, especially focused on the effect of upgrade CRT in patients with pacing-induced cardiomyopathy (PiCM).

Methods: The PiCM was defined by the new-onset dilated cardiomyopathy following pacemaker implantation in patients with baseline normal ejection fraction (>50%). Electrico-mechanical reverse remodeling and clinical outcomes were compared among the de-novo (n=62), PiCM upgrade (n=7), and non-PiCM upgrade (n=8) CRT groups.

Results: The PiCM upgrade group showed a significantly greater electrico-mechanical reverse remodeling compared to the de-novo CRT or non-PiCM upgrade groups at 6-month follow-up. The rate of super-responder was significantly higher in the PiCM upgrade than the other CRT groups. The group factor of the PiCM upgrade was identified as an independent predictor of super-responder in multivariate analysis (odds ratio, 13.03; 95% CI, 1.32-129.1; P=0.03). During the median follow-up of 15.8 months, the PiCM upgrade group showed the lowest rate in composite clinical outcome including cardiac death, heart transplantation, and heart failure-related rehospitalization (P= 0.17).

Conclusions: The upgrade CRT for PiCM patients showed a better performance in terms of electrico-mechanical reverse remodeling and composite clinical outcomes, compared to de-novo implantation or upgrade for non-PiCM patients.

FAILURES IN RADIOFREQUENCY CATHETER ABLATION OF PATIENTS WITH WOLFF-PARKINSON-WHITE SYNDROME: AN 8-YEAR RETROSPECTIVE STUDY OF FACTORS RELATED TO FAILURE OF INITIAL RFA

Maria Bianca De Guzman, Htoo Lwin Kaung, Paul Lin, Daniel Chong, Boon Yew Tan, Kah Leng Ho, Chi Keong Ching, Wee Siong Teo

National Heart Centre Singapore, Singapore

Introduction: Radiofrequency catheter ablation (RFA] for Wolff-Parkinson-White (WPW] Syndrome is successful in the majority of patients. However, failure does occur in a small percentage of this population. This study aims to describe the WPW patients who underwent RFA and to report factors associated with acute failure of the procedure.

Methods: This is a retrospective study of all cases of WPW patients, including those with concealed pathways and pre-excited, who underwent RFA from June 2008 until April 2016.

Results: A total of five hundred WPW patients underwent RFA during the specified time period. Seventy-two percent (72%, n=360] of the patients were males, and eighty percent (80%, n=402] were Chinese. Patients' ages ranged from 9 years to 80 years, with the mean age of 35+10 years. Of the 500 cases reported, 25 patients (5%] had failure of initial RFA. Eighty percent (80%, n=20] of these failed cases were males. Seventy six percent (76%, n = 19] were Chinese. The age of these patients ranged from 11-80 years. Among those with failed RFAs, 64% (n=16] had right-sided pathways and 36% (N = 9] had left sided pathways. For those with right-sided pathways, five were found in the posteroseptal region, four in the parahisian region, and six in the right free wall. One patient had multiple right-sided accessory pathways. For those with left-sided pathways, two were in the left posteroseptal region and seven were in the left free wall site. Associated congenital heart disease, due to Ebstein anomaly, was seen in two patients with failed initial RFA.

Conclusions: Among patients with failed RFA, it was found that the majority of the patients were males. The most common site for failure are right-sided pathways, mostly in the right free wall. Presence of congenital and structural abnormalities, such as Ebstein anomaly, also contributed to failure of initial RFA in two subjects.

INCIDENCE AND RISK FACTORS OF ATRIAL FIBRILLATION AFTER CAVOTRICUSPID CATHETER ABLATION IN PATIENTS WITH "ISOLATED" TYPICAL ATRIAL FLUTTER

Peter Novikov, Nikolai Shlevkov, Alexander Pevzner, Evgeni Maykov, Nikolai Mironov, Yuri Mareev, Sergei Sokolov, Sergei Golitsyn

Russian Cardiology Research and Production Complex, Moscow, Russian Federation

Introduction: Radiofrequency ablation (RFA) is an effective treatment for typical atrial flutter (AFL). However, previous studies showec wide variability of new-onset atrial fibrillation (AF) and analysis of AF occurrence factors showed contradictory results. Aim: To determine factors of new-onset atrial fibrillation occurrence after cavotricuspid isthmus (CTI) radiofrequency ablation in patients with "isolated" typical atrial flutter

Methods: In this study we included 28 patients (24 men (86%), mean age 55±11 years], with paroxysmal (n = 15, 48%) or persistent (n= 16, 52%) AFL, without any documented history of AF. All patients underwent successful RFA, reaching bidirectional conduction block through the CTI as a procedural endpoint. During follow-up period (mean 24+15 months] after ablation patients were divided into two groups: Group №1 -"with AF", group №2- "without AF". Univariate analysis was performed between the following groups in total of 39 clinical characteristics including age, presence and duration of arterial hypertension, coronary artery disease, thyroid disease, diabetes mellitus, atrial flutter features, echocardiography data, electrophysiology study data (intraatrial and interatrial conduction time, effective refractory periods in different right atrium sites, induced atrial fibrillation during programmed and rapid atrial stimulation].

Results: At the end of Mow-up AF occurred in 17 (60%) patients, of which 3 (10%) patients had persistent AF. There was no statistical significance between two groups by all characteristics, except duration of hypertension history. AF significantly more often occurred in patients with long-term history of arterial hypertension (p=0.02), 6 year anamnesis of atrial hypertension had 80% sensitivity, 89% specificity 80% positive predictive value).

Conclusions: Sustained AF was observed during follow up after cavotricuspid isthmus ablation in 60% of patients with "isolated" typical atrial flutter. Long-term history of hypertension is an important predictor of AF occurrence in this cohort of patients.

History of hypertension, years

O 20 40 60 80 100

100- Specificity

Image 1. ROC- analysis of hypertension history, as a predictive factor in atrial fibrillation occurrence after cavotricuspid isthmus ablation in patients with "isolated" typical atrial flutter.

Comment: Dividing value- 6 years, sensitivity 80%, specificity 89%, positive

MO 3-07

THE PULMONARY VENOUS ANTRUM IN PATIENTS WITH PERSISTENT AF AND HEART FAILURE-ELECTROPHYSIOLOGIC AND ELECTRO-ANATOMICAL ASSESSMENT

Sandeep Prabhu12, Alex Voskoboinik12, Kah Peck1, Alex Mclellan12, Liang-han Ling12, Bupesh Pathik3, Chrishan Nalliah3, Geoff Wong3, Siobhan Lockwood4, Geoff Lee3, Sonia Azzopardi1,2, Justin Mariani1,2,Andrew Taylor1,2, Jonathan Kalman3, Peter Kistler1,2

'Alfred Health, Melbourne, Australia; 2Baker ¡01, Melbourne, Australia;3'Royal Melbourne Hospital, Melbourne, Australia; Monash Health, Melbourne, Australia

Introduction: Heart failure (HF) is associated with increased recurrence of AF following interventional or other rhythm control strategies. We performed detailed electrophysiologic and electroanatomic mapping of the PV antrum in patients with and without HF

Methods: Consecutive patients undergoing AF ablation with PeAF and LVEF<45% (HF group) were compared to LVEF>55% (Normal LV (NLV) group). In AF, PVCL was recorded via a multipolar catheter in each PV and the left atrial appendage (LAA) for 100 consecutive cycles. The average PV cycle length (PVCL) of all 4 veins (PV4Vaw5rage), the fastest PV average (PV^wrage] and the overall fastest CL of any PV (PVfast) relative to the average LAA cycle length (LAAaverage), was determined. Following OCR, high density mapping of the LA including the PV antrum using a contact force catheter (points> 10 g) was performed to determine voltage, scar, fractionation and conduction velocity (CV).

Results: 28 patients (age 58+8, AF duration 11 ±8.6 months) were enrolled (HF=13, NLV= 15). The HF group had significantly higher PV4Vav-erage/LAAaverage, PVFVaverage/LAAaiverage and PVfast/LAAaverage ratios, compared to NLV group. The PV antrum in HF had more fractionation, scar and reduced tissue voltage, without difference in CV. In the HF group, reduced tissue voltage was more pronounced in the PV antrum thar non-antral regions (Bipolar: 1.36+0.5 vs. 1.95+0.8 mV, p=0.016) and fractionation (37 vs. 23%, p=0.009), but not in NLV group.

Conclusions: HF is associated with reduced relative PVCL and increased antral structural remodelling compared to NLV. This may in part explain an increased propensity to AF in HF with implications for ablation strategy.

Baseline Characteristics HF (n—13) NLV (n=15) P value

LVEF 33.7 ± 7% 60.9 ± 3.1% <0.001

LA diameter (mm) 48 + 4 47 ± 10_ 0.73

PV 4Vaverage (4 vein average - over 100 cycles) 177 ±26 162 ± 19 0.09

PV FVaveragc (fastest vein - over 100 cycles) (ms) 164 ± 24 152 ± 16 0.11

PV fast (shortest CL over 60s of any vein) (ms) 122 ±18 95 ± 17 <0.001

LAA average (ms) 167 ± 20 164 ± 18 0.73

PV 4Vaverage (4 vein average) / LAA average 1.06 ± 0.05 0.98 ± 0.09 0.02

PV FVaveragc (fastest vein average) / LAA average 1.00 ± 0.07 0.91 ± 0.09 0.04

PV fast / LAA average 0.73 ±0.05 0.55 ± 0.17 <0.001

PV 4Vaverage 1 LAA average < 1 {% patients) 92% 40% 0.004

PV fast / LAA average < 69% (% patients) 80% 15% 0.002

Electroanatomical mapping (Pulmonary venous antral su bstrate)

Bipolar voltage (mV) 1.36 ± 0.48 2.02 ± 0.70 0.031

Unipolar voltage (mV) 2.12 ± 0.69 3.04 ± 0.90 0.003

Complex electrograms (%) 37.0 ± 17% 15.3 ± 15% <0.001

Low voltage (%) (<0.5mV bipolar) 23.4 ± 19.1% 10.1 ± 11.8% 0.024

Presence of any scar (<0.05mV bipolar, % of patints) 54% 10% 0.0019

Conduction Velocity (m/s) 1.01 ±0.22 1.09 ±0.17 0.24

MO 3-08

LEFT ATRIAL PRESSURE RESPONSE DURING INCREMENTAL DUAL CHAMBER PACING IN THE PATIENTS WITH ATRIAL FIBRILLATION : THE CONCEPT OF ADAPTATION AND STIFFNESS

Seung-Young Roh, Hee-Soon Park, Kwang No Lee, Yong-Soo Baek, Jaemin Shim, Jong-Il Choi, Young-Hoon Kim

Korea University Anam Hospital, Seoul, Republic of Korea

Introduction: Atrial fibrillation (AF) is associated with left ventricular diastolic dysfunction and atrial remodeling. We hypothesized that left atrial (LA) pressure change as heart rate reflects functional remodeling of LA in the patient with AF.

Methods: We measured peak LA pressure (LAPp) response as heart rate (HR) change by incremental dual chamber pacing during sinus rhythm in patients who underwent catheter ablation (CA) needs LA assess. The degree of late gadolinium enhancement (LGE) of LA ir cardiac MR (CMR) was checked in patient with AF. LAPp response was compared between 4 groups: group 1 AF patients with LGE <25 (n= 120), group 2 25^LGE<50 (n=50), group 3 LGE>>50, control) patients without AF (n=34).

Results: AF was induced by pacing to older (58 vs. 53 years) patients with longer baseline cycle length (BCL) (1,072 vs. 940 ms) (both p=0.02). Baseline LAP in group 3 was significantly increased compared to group 1, 2 and control (30 + 11 vs. 21 ±6, 24±7 and 19 ±5, p<0.001). LAPp was gradually increased as HR change in all groups (p<0.001). An increment of LAPp at pacing of 300ms was significantly different in all 4 groups (77+37, 65+30, 42+21, and 92+20, % in each group, p=0.01). The LGE in CMR was significantly associated with baseline LAPp (r=0.497), response of LAPp (r=-0.266) (all p<0.05). LGE in CMR ([B]=0.082; 95% CI 1.024-1.150; p=0.006) and LVEF ([B]=0.072; 95% CI 0.780-0.993; p=0.038) were independent predictors of low UPp response (<10 mmHg).

Conclusions: The response of LAPp during incremental pacing in AF patients was lower than in control group. It is associated with LGE degree in CMR among patients with AF. The clinical implication of this association warrant further investigation.

lOOO SOO 600 400 350 300

Pacing CL, ms

CIRCULATING LEPTIN PREDICTS IMPROVEMENT IN COGNITIVE FUNCTION AFTER CATHETER ABLATION FOR ATRIAL FIBRILLATION : 1-YEAR FOLLOW-UP DATA

Tae-Hoon Kim1, Ki-Woon Kang2, Jae-Sun Uhm1, Boyoung Joung1, Moon-Hyoung Lee1, Eosu Kim1, Hui-Nam Pak1

1Yonsei University Severance Hospital, Seoul, Republic of Korea; 2Eulji University Hospital, Daejeon, Republic of Korea

Introduction: Atrial fibrillation (AF) is associated with impaired cognitive function (CogF) and/or dementia, but it is unclear whether rhythm control of AF recovers CogF. We explored whether radiofrequency catheter ablation (RFCA) improved CogF, and evaluated several predictive biomarkers.

Methods: This observational cohort study included 290 patients (73.4% male, 60.0+10.8 years of age, 31.8% with persistent AF) who underwent RFCA for AF and 15 controls who receiving no rhythm control drugs or RFCA, and measured the Montreal Cognitive Assessment (MoCA) score one day before, 3 months after and 1-year after the procedure. We defined impaired CogF as a MoCA<23, and multiple circulating biomarkers were evaluated for the prediction of CogF improvement.

Results: 1) Pre-RFCA CogF impairment was detected in 67 out of 290 (23.4%) patients who undergoing RFCA, and found to be assoaatec with old age (p<0.001), being female (p<0.001), hypertension (p=0.005), stroke/TIA (transient ischemic attack) history (p=0.001), larger LA volume index (p=0.001) and higher circulating leptin levels (p<0.001). 2) MoCA scores improved 3 months after RFCA (24.37+3.52 tc 25.67+3.18, p<0.001), particularly in the visuoexecutive, attention, language, abstraction, and delayed recall function subdomains. 3) MoCA scores also improved in controls (23.87+4.97 to 24.67+4.59, p=0.028), and showed no significant difference between 290 patients who underwent RFCA and 15 controls (post 3 month-pre-RFCA MoCA score; 1.32 + 2.13 vs. 0.80 + 1.26, p=0.352). 4) These improvements after RFCA were maintained 1-year after the RFCA (25.82 + 2.94 to 26.31+2.72). 5) Low pre-RFCA MoCA scores (odds radio [OR] 0.73; 95%CI 0.66 to 0.81), larger LA volume index (OR 1.01; 95%CI 1.00 to 1.02), and high plasma levels of leptin (OR 1.22; 95%CI 1.06 to 1.39) were associated with post-AF ablation improvements in CogF.

Conclusions: About a quarter of the patients who underwent AF catheter ablation had underlying impaired CogF, but reducing the AF burden by RFCA significantly improved CogF. Our results suggest the important role of RFCA and potential involvement of metabolic hormone (leptin) in cognitive protection in patients with AF.

IMPACT OF CHEMICAL ABLATION OF THE MARSHALL VEIN ON CREATION OF MITRAL ISTHMUS BLOCK

Yasuteru Yamauchi

Yokohama City Minato Redcross Hospital, Yokohama, Japan

Introduction: Mitral isthmus (MI) is accepted for ablation target of peri-mitral atrial flutter. However, it is sometimes difficult to create complete conduction block at MI. Marshall Vein (MV) always anatomically courses across MI. Therefore, ethanol injection into MV (EIMV) has a profound influence on construction of MI block. In this study, we analyzed the extent of ablated area produced by EIMV, and evaluated clinical impact of EIMV on construction of complete MI block.

Methods: 38 patients with atrial fibrillation (AF) who underwent EIMV concomitant with cryoballoon (CB) guided pulmonary vein (PV) isolation were involved. EIMV was done first prior to PV isolation. After PV isolation, we developed a voltage map around MI using merged CT image reconstructed by 3D-mapping system. We analyzed the extent of low voltage area (LVA), which was defined as less than 0.5 mV, especially around MI. Then, we ablated survived endocardial sites of other than LVA on the MI line with maximum radiofrequency (RF) energy of 35 W in order to create complete MI block. If endocardial RF ablation failed to create MI block, we performed coronary sinus (CS) ablation with maximum RF energy of 25 W.

Results: Total amount of ethanol was 4.4+0.8 mL (2-6 mL). In all patients, LVA was always present at PV ridge site. Total length of MI line was 38.8+7 mm (25-54 mm). Length of LVA on MI line was 21.9+7 mm (10-36 mm), which accounted for 56 + 14% (25-80%), and LVA area was 5.7+3.4 cm2 (0.7-13.8 cm2). The distance between left inferior PV and the ostium of MV was 23.4+7.9 mm (7-40 mm). Length of LVA within left atrial appendage was 17.2+8.9 mm (2-36 mm). The size and shape of LVA was vastly different in each patient, and had no significant relationship to total amount of ethanol. Complete MI block was achieved in 36 of 38 (95%) patients. In all patients, LVA was always present at PV ridge site. In successful 36 patients, the average number of endocardial RF application was 6.8+4.4, and intra-CS ablation was needed in 17 (47%) patients to create complete MI block. No complications occurred.

Conclusions: LVA was always created at PV ridge site by EIMV, and LVA on MI line accounted for more than half of total length of MI. EIMV can safely and dramatically improve achievement of complete MI block, although intra-CS ablation is required in about half of patients.

CATHETER ABLATION MO 3-11

FEASIBILITY AND CLINICAL USEFULNESS OF HIGHRESOLUTION LEFT ATRIAL SOUND MAP AS A RELIABLE GEOMETRY

YeongHwa (Eiwa) Chun (Zen]

Takeda Hospital, Kyoto, Japan

Introduction: Usually atrial fibrillation (AF) ablation is performed under fluoroscopic guide and the image integration onto pre-made three dimensional computed tomography (3DCT) of left atrium (LA) in electro-anatomical mapping system. The recent major topic is how the operator can reduce fluoroscopic time. We have already invented the High-Resolution Sound Map using an intra cardiac echo catheter (ICE) equipped with a magnetic sensor, SOUNDSTAR&#174; for CARTOSOUND module of CARTO&#177;3. We assess that AF ablatior with this Sound Map may reduce the fluoroscopic time.

Methods: High-resolution sound map was created using the SoundMap function of CARTO SOUND&#177; module. The 3D LA image is reconstructed by multiple 2D LA contours drawn with ultrasound fans. These LA contour were obtained by manipulation of the ICE not only from right atrium, but from LA by navigation of this ICE to LA via atrial septal puncture hole. Clear echo contour of the left pulmonary vein (PV), left atrial appendage, anterior ridge area of left PVs and right PVs were easily drawn especially from LA. AF ablation was performed with this map as a optimal LA geometry in total 468 cases from February 2013 to June 2016. We assessed the feasibility and clinical usefulness of this method for AF ablation in these cases. We extract first 50 cases as group F and latest 50 cases as group L to compare, creating sound map time, procedure time and fluoroscopic time between them.

Results: Among these cases, there were 48 cases AF ablation without any image information of LA excluding Sound Map. In total, procedure time is 67 &#177; 15, fluoroscopic time is 28 &#177; 15, making sound map time is 23 &#177; 6 (min). The comparison data between group F and L is shown in the table below.

Comparison Data

Procedure time Creating sound map Fluoroscopic time

group F 72 &#177,28 26 &#177,8 36 &#177,17

group L 36 &#177,17 12 &#177,5 8 &#177,3

Conclusions: This study showed that there is a reduction of procedure time and fluoroscopic time with Sound Map and the more experience gained, the more Sound Map time can be reduced. This Sound Map provides precise anatomical information of LA as a reliable anc real time geometry for AF ablation. Circumferential PV isolation was safely and successfully performed without 3DCT of LA. In conclusion, High-Resolution Sound Map is useful for the AF ablation.

MO 3-12

LONG-TERM OUTCOMES OF CATHETER ABLATION OF ATRIAL FIBRILLATION: A MORE THAN 10 YEARS OF EXPERIENCE

Yong-Soo Baek, Jong-Il Choi, Hee-Soon Park, Anupam Jena, Kwang-No Lee, Seung-Young Roh, Jinhee Ahn, Dong-Hyeok Kim, Jaemin Shim, Jin Seok Kim, Hong Euy Lim, Sang-Weon Park, Young-Hoon Kim

Korea University Medical Center Seoul, Republic of Korea

Introduction: Catheter ablation of atrial fibrillation (AF) has been an established therapeutic modality for the treatment of patients with symptomatic AF. However, data regarding the long-term outcomes of AF ablation are still lacking. We sought to investigate the long-term outcomes over 10-year after catheter ablation in patients with AF.

Methods: From 2004 to January 2016, a total 2,221 consecutive patients who underwent catheter ablation, including circumferential pulmonary vein isolation (CPVI) were studied (mean 55±11 years old, 20.3% female, 59.0% paroxysmal AF). Additional ablations were performed according to AF type and the physicians' discretion. Clinical characteristics, imaging parameters, ablation findings and outcomes were analyzed in all patients. Late gadolinium enhancement (LGE) in cardiac magnetic resonance image (MRI) were also assessed.

Results: CPVI with or without ablation of cavo-tricuspid isthmus was accomplished in 49.2% of the patients. More extensive ablation prevailed in persistent AF types (p<0.001). Repeated ablations were performed in 480 patients (2nd procedure=418, 3rd procedure=56, anc 4th procedure=6, respectively). Patients with persistent AF underwent significantly more repeat procedures than those with paroxysmal AF (26.6% vs. 13.4%, p<0.001). The patients with multiple procedure had higher proportions of atrial tachycardia or atrial flutter thar those with index procedure (42.8% vs. 59%, p<0.001). After the index procedure, sinus rhythm (SR) was present in 1,490 of 2,221 (67.1%) during a median follow-up period of 54 months. After redo procedures of 448 patients, 83.3% of the patients remained in SR. In sub-analysis, LGE-MRI scar burden in patients with CR were higher than those without CR (21.8 + 13.7% vs. 36.2+23.9, p<0.001). In the multivariate analysis, persistent AF (HR 2.203, 95% CI 1.396-3.477, p<0.001) and MR LGE >25% (HR 1.944, 95% CI 1.224-3.087, p=0.005) were significantly associated with AF recurrence after catheter ablation.

Conclusions: In patients with AF, repeat procedures of catheter ablation showed a similar long-term outcome to single procedure during 10 years follow-up. And, this study supports that AF substrate that was represented by persistent AF and MR-LGE is associated with recurrence after catheter ablation

YIA SESSION [BASIC]

BASIC/TRANSLATIONAL SCIENCE

YIA 1-01

CAN A SODIUM CHANNEL BLOCKER CAUSE WENCKEBACH ACTION POTENTIAL CONDUCTION WITHIN THE RABBIT LEFT VENTRICLE?

Guoliang Li, Lin Yang, Yunyun Li, Xuemei Zhang, Meng Liu, Miaomiao Cao, Ganxin Yan

The First Affiliated Hospital, Xian Jiaotong University, Xian, China

Introduction: Wenckebach conduction in the ventricular myocardium has been rarely reported. Here, we examined whether a sodium channel blocker flecainide with a strong use-dependent property could produce Wenckebach-type conduction in the rabbit left ventricle ir which the sodium current is responsible for conduction.

Methods: The isolated arterially perfused rabbit left ventricular wedge preparations, in which a transmural ECG was recorded simultaneously with epicardial (Epi) and endocardial (Endo) action potentials (APs), were paced at rates from 1 Hz to 3 Hz.

Results: At control perfusion, ventricular conduction (80.0± 1.3 ms, n=9) remains unchanged among different pacing rates. Flecainide at 10 pM produced QRS widening, indicating conduction delay. As increasing at pacing rates, QRS complexes broadened further, and the conduction time from Endo to Epi prolonged gradually to a point when the conduction block from Endo to Epi occurred, i.e. Wenckebach-type conduction delay (Figure 1A). Following the conduction block, the same pattern of Endo to Epi AP propagation resumed. A phenomenon indicates use-dependent blockade of the fast sodium channel. The results from 9 preparations in Figure 1B showed that the transmural AP conduction time was 76.0± 1.8, 83.1 ±1.7, 95.1 ±3.0 and 98.7±2.9 ms (n=9, Figure 1B) respectively prior to the block. X of 9 preparations developed ventricular tachycardia.

Conclusions: The sodium channel blocker flecainide can cause Wenckebach-type conduction between ventricular Endo and Epi via use-dependent inhibition of the sodium current. This novel finding indicates that the selective conduction block between Endo and Epi by the sodium channel blockers may facilitate the development of reentrant ventricular arrhythmias.

BASIC/TRANSLATIONAL SCIENCE

YIA 1-02

ACUTE AND CHRONIC SUPPRESSION AND LOSS OF CIRCADIAN VARIABILITY OF CARDIAC SYMPATHETIC NERVE ACTIVITY IN A CANINE MODEL OF PREMATURE VENTRICULAR CONTRACTION-INDUCED CARDIOMYOPATHY

Ricardo Cardona Guarache1, Karoly Kaszala1, Anthony Minisi1, Shien-Fong Lin2, Kenneth Ellenbogen1, Jose Huizar1, Alex Tan1

Virginia Commonwealth University Richmond, United States; 2Indiana University School of Medicine, Indianapolis, United States

Introduction: Premature ventricular contractions (PVCs) are implicated in development of cardiomyopathy. A potential mechanism is autonomic dysregulation. However, the autonomic changes in a PVC-induced cardiomyopathy are poorly understood.

Methods: We developed a canine model of PVC-induced cardiomyopathy. We implanted a pacemaker and delivered bigeminal right ventricular PVCs at a coupling interval of 220-250 ms in 6 canines over 3 months. Data Sciences International radiotelemetry devices were implanted for continuous ambulatory recordings of left stellate ganglion (SGNA) and left cardiac vagal nerve activity (VNA) (n=6). In-vivc left ventricular systolic pressure (LVSP) (n=2/6) and ambulatory systolic blood pressure (SBP) was recorded (n=3/6).

Results: Acute PVC initiation immediately (<1 minute) increased LVSP (N=4) from 78+8 to 101 +6 mmHg (p=0.006), and ambulatory SABP (N=3) from 102+4 to 128+7 mmHg (p=0.06), and reduced 2-min averaged SGNA from 33.2+8.7 to 21.3 + 7.1 uV-s (N=6, p=0.008) and VNA from 24.1+5.1 to 12.4+6.2 uV-s (p=0.008). Elimination of PVCs reversed all the above findings. After 24-hours of PVCs, there was a decline in averaged daily SGNA 33.2+8.7 to 18.3 + 11.7 uV-s (p=0.01) but not VNA (from 23.1 + 17.8 to 21.7 + 16.2 uV-s) (p=0.21). More chronic (3-month) PVC exposure reduced averaged daily SGNA from 86.7+60 to 78 + 58 uV-s (p=0.02) without change in VNA (from 26.1 + 25.1 to 25.1 + 13.4 uV-s (p=0.47). There was a loss in circadian variability (daily standard deviation) of SGNA from 87.1 +58.6 to 73 + 57.4 uV-s (p=0.014), and peak daily SGNA response to activity declined from 547.5+277.7 to 384.3 + 252.1 uV-s (p=0.038).

Conclusions: Acute and chronic bigeminal PVCs are associated with a significant reduction and loss of circadian variability of cardiac sympathetic nerve activity but not vagal nerve activity. The mechanism may be a baroreflex mediated suppression of sympathetic outflow The suppression and loss of circadian variability of cardiac sympathetic nerve activity may have implications for the development of PVC induced cardiomyopathy.

BASIC/TRANSLATIONAL SCIENCE

YIA 1-03

SEROTONIN REGULATES QT-INTERVAL: ACCELERATION OF CARDIAC REPOLARIZATION BY ENHANCED KV4.3 MEMBRANE TRAFFICKING

Shanyu Cui, Boyoung Joung

Division of Cardiology, Yonsei University College of Medicine, Seoul, Republic of Korea

Introduction: Elevated maternal serotonin (5-hydroxytryptamine, 5-HT) production is an important determinant of normal fetal development. However, what roles the elevated serotonin plays in the electrophysiology of the mothers heart has not been studied. In the present study, we therefore assessed the relationship between QTc duration and serotonin and studied underlying mechanisms.

Methods: Patch clamp; Immunoprecipitation; Immunostaining; Western blotting.

Results: During pregnancy, 5-HT and tryptophan hydroxylase 1, a rate-limiting enzyme of serotonin synthesis, were markedly increasec in hearts and serum. We measured QT intervals and ventricular potassium outward currents in wild-type (WT) and 5-HT3a receptor knock-out (HtrSa-'] mice at non-pregnant (NP) and late-pregnant (LP) state. The 5-HT as well as m-CPBG, an Htr3 agonist, increased /peak and /to,f densities with the shortening of QTc duration in WT NP, but not in WT LP and Htr3a~A mice. Additionally an Htr3a antagonist, ondansetron (5 pM) decreased /peak and /to,f only in WT LP, but not in WT NP mice. In contrast, /peak and /to,f densities were unchanged upon 5-HT and m-CPBG application in left ventricular myocytes freshly-isolated from the Htr3a'"/""LP mice. Kv4.3 protein and Htr3a is co-localization in the membrane and t-tubule of cardiomyocytes. Co-immunoprecipitation showed that Kv4.3 protein directly interacts with 5-HT3a receptor. Moreover, the binding between 5-HT3a receptor and Kv4.3 was facilitated by 5-HT. This increase was mediated by 5-HT3a receptor dependent promotion of Kv4.3 channel trafficking to the cell membrane. However, these findings were not observed ir WT LP mice. The heat-shock protein-90 (Hsp90) inhibitor geldanamycin abolished 5-HT-induced increase of /peak and /to,f densities. Finally, we evaluated and found that serotonin could shorten QTc interval by increasing potassium outward currents in rat and rabbit.

Conclusions: Elevated 5-HT levels were associated shorter QTc intervals by acceleration of /peak and /to,f densities in mouse, rat and rabbit. 5-HT acts on Kv4.3 channels via enhanced 5-HT3a-receptor-medicated Hsp90 interaction, augments membrane trafficking and thereby increases repolarizing current. These results provide mechanistic insights into hormonal control of ventricular repolarization.

BASIC/TRANSLATIONAL SCIENCE

YIA 1-04

ROLE OF ADJUNCTIVE ANTI-FIBROTIC THERAPY WITH TRANILAST IN REVERSING ATRIAL REMODELLING IN SPONTANEOUSLY HYPERTENSIVE RATS

Shivshankar Thanigaimani1, Do Yeon Kim1, Jim Manavis1, Darren Kelly2, Pawel KukLik1, Prashanthan Sanders1, Dennis Lau1

University of Adelaide, Adelaide, Australia; 2University of Melbourne, Melbourne, Australia

Introduction: Tranilast has been shown to be beneficial in preventing atrial remodelling in animal models of atrial tachypacing and hypertension (HTN). However, it remains unknown whether anti-fibroticagent has a role in reversing the abnormal changes seen with established atrial substrate.

Methods: Twelve months old spontaneously hypertensive rats (SHR, n =32) and normotensive Wistar-Kyoto controls (WKY, n=8) were studied. The SHR group was divided into HTN controls (n =8) and treatment groups: Perindopril (PRD-0.5 mg/kg/day, n=8); Tranilast (Tran-600 mg/kg bid, n=8); PRD+Tran combination (n=8) for 4 weeks. Electrophysiological studies of superfused atria were performed using a custom multi-electrode array to assess effective refractory period (ERP), conduction and AF i nducibility followed by detailed histological and immunohistochemistry analysis.

Results: Hypertension resulted in significant atrial electro-structural and molecular abnormalities leading to increased AF i nducibility (HTN vs. WKY normotensive controls, Table). PRD, TRAN and PRD+TRAN treatments improved atrial conduction, interstitial fibrosis, myocyte hypertrophy and various signalling molecules expressions leading to reduced AF vulnerability. PRD+TRAN treatment resulted in pronounced beneficial reverse remodelling compared to single agent therapy

Conclusions: Tranilast has similar reverse remodelling effects in hypertensive atria as compared to Perindopril despite not affecting blood pressure levels. Additional beneficial effects were evident with the use of anti-fibrotic agent in combination with anti-hypertensive therapy.

BASIC/TRANSLATIONAL SCIENCE

YIA 1-05

MICROVESICLES FROM MESENCHYMAL STEM CELLS IMPROVES CALCIUM REGULATION BY HISTONE DEACETYLASE-6 INHIBITION IN TACHYCARDIA MODEL OF HL-1 MYOCYTE

Yoo Ri Kim1, Hyo-Eun Kim2, Hyewon Park2, Hyelim Park2, Sanyou Chui2, Seung-Hyun Lee2, Nam Kyun Kim2, Hui-Nam Pak2, Moon-Hyoung Lee2, Michael Kim1, Boyoung Joung2

1The Catholic University of Korea, incheon, Republic of Korea; 2Yonsei University College of Medicine, Seoul, Republic of Korea

Introduction: Plasma microvesides (MV) from mesenchymal stem cells (MSC) has known as cell to cell messengers. However, the role of MV which regulate molecular interactions in atrial fibrillation (AF) remain unfortunately much unknown. This study investigated that MV derived from hypoxic conditioned MSCs help to prevent calcium overloading in atrial myocytes during tachycardia.

Methods: MVs were isolated from plasma by differential centrifugation and microfiltration. The HL-1 atrial cardiomyocytes were preparec with normal paced (1 Hz) or tachy-paced (5 Hz). Before pacing, HL-1 cell were treated with the MVs. The effects of MV on paced HL-1 cell were examed using a patch clamp, a confocal Ca2+ imaging, western blot analysis and imunofluorescent staining.

Results: Tachypacing induced shortening of APD, Ca2+ overload, activation of Histone Deacetylase-6 (HDAC-6) and depolymerization of microtubules in the HL-1 myocyte. However, MV inhibited the transient Ca2+ reductions in tachy-paced (TP) HL-1 myoctes and L-type Ca2" current were also preserved with MV. Depolymerization of microtubues by tachypacing were also prevented by MV via HDAC-6 pathway.

Conclusions: MV successfully preserved calcium regulation and de-activation of HDAC-6 in TP HL-1 cell model. This results suggest that MVs would be a therapeutic option for control of atrial tachyarrhythmia.

BASIC/TRANSLATIONAL SCIENCE

YIA 1-06

SPINAL CORD STIMULATION SUPPRESSES ATRIAL FIBRILLATION BY ACTIVATING CHOLINERGIC ANTIINFLAMMATORY PATHWAY

Zixuan Dai

Renmin Hospital of Wuhan University, Wuhan, China

Introduction: The aim of the present study was to determine whether spinal cord stimulation (SCS) could inhibit atrial fibrillation (AF) in-ducibiLity in paroxysmal AF dog model and to explore its underlying mechanism.

Methods: First, all the dogs were implanted pacemakers for long-term intermittent right atrial pacing (RAP) at 400 b.p.m. for 8 hours a day. Then the dogs were divided into four groups: control group (n=6), vagus nerve stimulation group (VNS, n=8), SCS group 1 (n=8), SCS group 2 (n=8). 8 weeks later, control group dogs were given no stimulation; VNS group dogs experienced low-level VNS for 30 minutes; SCS group 1 dogs experienced low-level SCS for 30 minutes, while SCS group 2 dogs underwent bilateral vagotomy and simultaneously received low-level SCS for 30 minutes. Effective refractory period (ERP), ERP dispersion and AF vulnerability were measured at pacing 8 weeks and SCS 30 minutes later. Five millilitres of venous blood were collected in thylenediaminetetraacetic acid vacutainers at the baseline, pacing 8 weeks, and after SCS.

Results: Compared with pacing 8 weeks later, VNS and SCS both induced a significant increase in ERP at left and right atrium and four pulmonary veins and ERP dispersion was decreased, along with the decrease in AF i nducibility. After bilateral vagotomy, these electrical physiological parameters had no changes before and after SCS. VNS suppressed the increasing trend of tumor necrosis factor a (TNF-a) and interleukin 6 (IL-6) in the atrial tissue and circulating blood by prolonged RAP. Correspondingly, the level of acetylcholine (ACH) and a7 subunit of the nicotinic acetylcholine receptor (a7nAchR) expression significantly increased. VNS also inhibited the phosphorylation of nuclear factor kB (NF-kB) signaling pathway related protein. SCS had the similar effects, but were eliminated by bilateral vagotomy.

Conclusions: SCS suppresses prolonged RAP-induced AF, which might related to the immunosuppressing function of VN. VN through its nerve endings release ACH activated CAP, thereby inhibit its downstream NF-kB signaling pathway and suppress the release of TNF-c and IL-6.

YIA SESSION [CLINICAL]

VENTRICULAR TACHYCARDIA & VENTRICULAR FIBRILLATION

YIA 2-01

UNIPOLAR AND BIPOLAR ELECTROGRAM CHARACTERISTICS OF RECURRENT CASES OF VENTRICULAR ARRHYTHMIAS UNDERGOING CATHETER ABLATION

Anupam Jena, Mohammad Iqbal, Hee-Soon Park, Yong-Soo Baek, Kwang-No Lee, Seung-Young Roh, Jaemin Shim, Jong-Il Choi, Young-Hoon Kim

Korea University Medical Center, Seoul, Republic of Korea

Introduction: Activation mapping guided catheter ablation (CA) of ventricular arrhythmias (VAs) is known to be effective, however, is limited in some cases when it is only relied on bipolar electrogram (EGM). We hypothesized that activation mapping with use of combined bipolar and unipolar EGM facilitates to identify the focal origin of VAs and results in reduction of recurrence rate of CA of VAs.

Methods: We retrospectively analyzed the data of patients who underwent CA of premature ventricular contractions (PVC) and ventricular tachycardia (VT). From 2001 to 2016 a total of 500 patients underwent ablation for PVC and VT. Out of those cases 56 patients underwent repeat ablation for recurrence of PVC and focal, non-reentrant VT. The EGM of the initial ablation and repeat ablations were compared for earliest local activation time, presence of discrete potentials, and polarity reversal. Where unipolar recordings were available they were analyzed for unipolar potential morphology (QS or non-QS), potential amplitude and activation slope. Unipolar activation slope was definec as the ratio of voltage and time interval from onset of QS to the nadir of S wave.

Results: The EGMs were compared between the initial and repeat ablations in 37 patients. The earliest local activation time prior to QRS onset was significantly less in the initial ablation procedure as compared to the repeat procedure (31.85 msec vs. 36.90 msec, p<0.01). The incidence of discrete potentials and polarity reversal were similar in both procedures (51% vs. 57%, p=0.8 and 62% in both the occasions, respectively). The unipolar voltage was similar in both occasions (6.94 mV in first ablations vs. 7.22 mV in repeat ablations, p=0.7). The unipolar activation slope was also similar in the initial and repeat ablations (0.156 mV/msec vs. 0.171 mV/msec, p=0.2). We started recording unipolar EGMs from 2011 in all cases of PVC and VT ablations. The recurrence rate (15 out of 261 patients, 5.7%) was significantly lower with routine use of combined unipolar and bipolar EGMs, as compared to the use of bipolar EGM alone (40 out of 239 patients, 16.7%).

Conclusions: Use of both bipolar and unipolar electrograms helps in better delineation of the sites of earliest activation for effective ablation of VAs. Use of unipolar electrograms in addition to bipolar electrograms is associated with lower long term recurrence rate.

VENTRICULAR TACHYCARDIA & VENTRICULAR FIBRILLATION

YIA 2-02

DETERMINING THE OPTIMAL DOSE OF ADENOSINE FOR UNMASKING DORMANT PULMONARY VEIN CONDUCTION FOLLOWING ATRIAL FIBRILLATION ABLATION: ELECTROPHYSIOLOGICAL AND HEMODYNAMIC ASSESSMENT. DORMANT-AF STUDY

Sandeep Prabhu1, VIncent Mackin2, Alex Mclellan1, Tuong Phan2, Desmond McGlade2, Kah Peck3, Alexandr Voskoboinik1, Bupesh Pathik4, Chrishan Nalliah4, Geoff Wong4, Sonia Azzopardi1, Geoff Lee4, Justin Mariani1, Andrew Taylor1, Jonathan Kalman4, Peter Kistler1

'Alfred Health and Baker IDI, Melbourne, Australia; 2Cabrini Health, Melbourne, Australia; Alfred Health, Melbourne, Australia; 4Royal Melbourne Hospital, Melbourne, Australia

Introduction: The significance of adenosine induced dormant pulmonary vein (PV) conduction in AF ablation remains controversial. The optimal dose of adenosine to determine dormant PV conduction is yet to be systematically explorec

Methods: Consecutive patients undergoing index AF ablation were prospectively enrolled. Each received 3 adenosine doses (12 mg, 18mg, 24 mg) in a randomized blinded order, immediately after PVI. Electrophysiological (PR prolongation, AV block (AVB] and PV reconnection] and hemodynamic (BP] parameters were measured.

Results: 339 doses (113/dose] assessed 191 PVs in 50 patients (66% male, 72% PAF, 52% hypertensive]. Dormant PV conduction occurred in 28% of patients (16.5% (32] of PVs]. All cases were associated with AVB (AVB: PV reconnection vs. no PV reconnection 100% vs. 83%, p=0.007]. AVB occurred more frequently at 24 mg vs. 12 mg (92% vs. 82%, p=0.019] but not vs. 18 mg (91%, p=0.62]. AVB duration progressed between 12 mg (12.0±8.9s], 18 mg (16.1 ±9.1s, p=0.001] and 24 mg (19.0+9.3s, p<0.001] doses. MBP fell further at 24 mg (MBP: 27 + 12 mmHg] and 18 mg (26 + 13 mmHg] dose compared to 12 mg (22 +10 mmHg vs., p<0.001]. A significant reduction in AVB in patients >110 kg (65% vs. 91% in 70-110 kg group, p<0.001] in response to adenosine was seen (see figure].

Conclusions: An adenosine dose producing AVB is required to unmask dormant PV conduction. AVB is significantly reduced in patients >110 kg. Weight and dosing variability may in part explain the conflicting results of studies evaluating the clinical utility of adenosine ir PVI.

YIA 2-03

PLASMA HOMOCYSTEINE LEVELS PREDICT EARLY RECURRENCE AFTER CATHETER ABLATION OF PERSISTENT ATRIAL FIBRILLATION

Yan Yao, Xin Du, Jianzeng Dong, Changsheng Ma

Beijing Anzhen Hospital, Beijing, China

Introduction: The clinical importance of early recurrence is increasingly reinforced for atrial fibrillation ablation as it is found to be a powerful independent predictor of late recurrence. It is of great significance to search for predictors of early recurrence. The study is designee to assess the association and the predictive value of plasma homocysteine (Hcy) with early recurrence in persistent atrial fibrillation patients after a single ablation procedure.

Methods: Two hundred and fifty-seven consecutive patients with persistent atrial fibrillation who underwent successful catheter ablatior were enrolled. Early recurrence of atrial tachyarrhythmia was documented within 3 months after ablation. The logistic regression analysis and Kaplan-Meier curve analysis were used to evaluate the association of Hcy with early recurrence.

Results: During the 3-month follow-up, 75 (29.2%) patients experienced recurrence. Patients with early recurrence were older, more likely to have larger left atrial diameter and higher CHA2DS2-VASc score (all p<0.001). Plasma homocysteine (Hcy) levels were significantly elevated in patients with early recurrence compared with those without early recurrence (15.1 +4.1 pmol/L vs. 12.4+3.7 pmol/L, p<0.001). In multivariate analysis, Hcy was significantly associated with early recurrence (OR 1.188, 95% CI 1.097-1.286, p<0.001). Hcy demonstrated a predictive value with AUC of 0.688 (95% CI 0.623-0.753, p<0.001). The optimal cut-off value was 14 pmol/L for Hcy (sensitivity 69%, specificity 59%). Patients with Hcy ^14 pmol/L had higher early recurrence rate compared with those with Hcy <14 pmol/L (41% vs. 22%, p=0.006).

VENTRICULAR TACHYCARDIA & VENTRICULAR FIBRILLATION

YIA 2-04

DIFFERENTIATION BETWEEN PAPILLARY MUSCLE AND FASCICULAR VENTRICULAR ARRHYTHMIA USING NOVEL ELECTROCARDIOGRAPHIC INDICES

Yao Ting Chang, Yenn-Jiang Lin, Fa-Po Chung, Li-Wei Lo, Yu-Feng Hu, Shih-Lin Chang, Jo-nan Liao, Tze-Fan Chao, Ta-Chuan Tuan, Chin-Yu Lin, Shih-Ann Chen

Taipei Veterans General Hospital, Taipei, Taiwan

Introduction: Papillary muscle ventricular arrhythmia [PM-VA] and fascicular ventricular arrhythmia [FVA] are characterized by different mechanism but similar morphology. Using electrocardiographic pattern for differential diagnosis may be suboptimal due to the close proximity of papillary muscle and conduction system.

Methods: The FW is in mechanism and only single beat of long CI should be observed after a preceding ectopy or capture beat. The higher morphology dispersion should be observed in PM-W due to the presence of multiple exits. We aimed at evaluating the feasibility of twe novel criteria, including [1] the high dispersion of arrhythmia morphology and [2] the presence of consecutive 2 beats of long coupling interval (CI].The morphology deviation was evaluated using all beats of ventricular arrhythmia before introducing any catheter inside left ventricles. An objective method of morphology-variability measurement was used that the first beat of VPC was selected as the template for matching algorithms based on the ECG average correlation algorithms [ECG-AC] embedded in the LabSystem Pro workstation. The presence of consecutive 2 beats of long CI was evaluated by using all the ventricular tachycardia during electrophysiology study and 24hour Holter monitoring. The difference between the CI0-1 and the CIave3 [ACI0-1-CIave3] were measured in the presence of a CI1-2 greater than CIave3. The presence of consecutive 2 beats of long CI was defined as Д [CI0-1-CIave3] >0.

Results: Total 39 patients with FVA and PM-W were admitted for catheter ablation and were enrolled consecutively in the present study Frequent ventricular ectopy but no sustained ventricular tachycardia were observed in all the patients with PM-W but not FVT. The morphology dispersion is higher in patients with PM-W than FW [ECG-AC 3.0+1.8 vs. 1.6 + 1.0]. The presence of consecutive 2 beats of long CI was observed in patients with PM-W but never in FW [44% vs. 0%].

Conclusions: The combination of novel criteria based on morphology dispersion and the characteristics of CI may well differentiate between FVA and PM-VT.

CLINICAL ELECTROPHYSIOLOGY

HEART RATE-PR INTERVAL DISSOCIATION PREDICTS CARDIOVASCULAR DEATH AND EVENTS: A NOVEL MARKER OF CARDIAC AUTONOMIC DYSREGULATION

Yap-Hang Chan1, Kai-Hang Yiu1-2, Sheung-Wai Li3, Chung-Wah Siu1-2, Chu-Pak Lau12, JoJo Hai12, Hung-Fat Tse12

Queen Mary Hospital, Hong Kong; University of Hong Kong, Hong Kong; Tung Wah Hospital, Hong Kong

Introduction: Our recent study identified counter-physioLogicat dissociation of resting HR and PR interval (HP Dissociation] as a novel marker of cardiac autonomic dysfunction. However, its clinical significance in risk prediction of adverse cardiovascular (CV] events was unknown.

Methods: We prospectively studied a clinical cohort of 550 patients with coronary disease, ischemic stroke and/or type 2 diabetes (mear age 66 years, male 69%, recruited during September 2005-April 2008; follow-up duration 63 ±11 mths] for major adverse cardiovascular events (MACE, defined as new-onset myocardial infarction, congestive heart failure [CHF], ischemic stroke, and CV death]. Heart rate-PR interval dissociation was defined as counter-physiological co-occurrence of increased PR interval (> median; 173.3 ms] and increasec resting HR (>median; 64.4 beats per minute [BPM]] as a marker of autonomic dysrregulation.

Results: Respectively 4% (22/550] and 15% (84/550] of patients developed CV death and MACE. HP dissociation (22% prevalence] was associated with new-onset myocardial infarction (p=0.002], CHF (p=0.003], CV death (p<0.001], and combined MACE (p<0.001]. Kaplan-Meier analyses revealed that HP dissociation was associated with reduced event-free survival from CV death (Log rank=17.7, p<0.001] and MACE (Log rank=26.2, p<0.001]. Multivariate cox proportional hazards regression showed that, adjusted for conventional CV risk factors, HP dissociation was an independent predictor for MACE (HR=3.7 [95%CI 1.7-8.2], p=0.001], above and regardless of baseline PR interval and heart rate.

Conclusions: HP dissociation is a novel independent predictor of MACE including CV death.

RADIOFREQUENCY CATHETER ABLATION IMPROVES THE QUALITY OF LIFE MEASURED WITH A SHORT FORM-36 QUESTIONNAIRE IN ATRIAL FIBRILLATION PATIENTS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Yun Gi Kim, Jaemin Shim, Jong-Il Choi, Young-Hoon Kim

Korea University Anam Hospital, Seoul, Republic of Korea

Introduction: The main purpose of performing radiofrequency catheter ablation (RFCA] in atrial fibrillation (AF] patients is to improve the quality of life (QoL] and alleviate AF-related symptoms. We aimed to determine the qualitative and quantitative effects of RFCA on the QoL in AF patients.

Methods: We performed a systemic review and meta-analysis using a random effects model. We searched for the studies that reportec the physical component summary score (PCS] and mental component summary score (MCS] of the short form-36, a validated system tc assess and quantify the QoL in AF patients, before and after RFCA in AF patients. PCS and MCS are T-scores with a mean of 50 and standard deviation of 10.

Results: Of the 470 studies identified, we included 13 studies for pre-RFCA vs. the post-RFCA analysis and 5 studies for treatment success vs. AF recurrence analyses. In the pre-RFCA vs. post-RFCA analysis, RFCA was associated with a significant increase in both the PCS (weighted mean difference [WMD]=6.33 [4.81-7.84]; p<0.001; Figure 1A] and MCS (WMD=7.80 [6.15-9.44]; p<0.001; Figure 1B]. The APCS (post-RFCA PCS-pre-RFCA PCS] and AMCS values were used for the treatment success vs. AF recurrence analysis. Patients with successful treatment had a higher APCS (WMD=7.46 [4.44-10.49]; p<0.001; Figure 2A] and AMCS (WMD=7.59 [4.94-10.24]; p<0.001; Figure 2B].

Conclusions: RFCA is associated with a significant increase in the PCS and MCS in AF patients. Patients without AF recurrence after RFCA had a better improvement in the PCS and MCS than the patients who had AF recurrence.

YIA 2-05

YIA 2-06

YIA 2-06

LATE-BREAKING TRIAL

VIRTUAL IN-SILICO MODELING GUIDED CATHETER ABLATION VS. EMPIRICAL ABLATION FOR LONGSTANDING PERSISTENT ATRIAL FIBRILLATION : MULTICENTER PROSPECTIVE RANDOMIZED STUDY

Hui-Nam Pak1, Jaemin Shim2, Young-Seog Oh3, Gi-Byung Nam4, Young Keun On5, Tae-Hoon Kim1, Seil Oh6, Byung-Hyun Lim1, Minki Hwang1, Eun-Bo Shim7

1Yonsei University Severance Hospital, Seoul, Republic of Korea; 2Korea University Cardiovascular Center; Seoul, Republic of Korea; Catholic University, Seoul, Republic of Korea; Asan Medical Center; Seoul, Republic of Korea; Samsung Medical Center Seoul, Republic of Korea; Seoul National University Seoul, Republic of Korea; 7Kangwon National University Chuncheon, Republic of Korea

Introduction: Radiofrequency catheter ablation (RFCA) for persistent AF (PeAF) still has a substantial recurrence rate. We recently developed an in-silico 3D AF model with clinically acceptable computing speed, and validated 86% match of the best virtual ablation lesion set and empirical ablation lesion set in retrospective study. We conducted prospective study to test feasibility, efficacy; and safety of virtual ablation guided RFCA (V-ABL), comparing with empirical ablation (Em-ABL) in patients with PeAF.

Methods: We included 108 patients with antiarrhythmic drug (AAD) resistant PeAF (77.8% male, 60.8 + 9.9 years old) who underwent RFCA, and randomly assigned to V-ABL (n=53) and Em-ABL (n=55). For V-ABL, we tested 5 different ablation lesion sets (circumferential pulmonary vein isolation (CPVI), CPVI+posterior box (PostBox) lesion, CPVI+PostBox+anterior line (AL), CPVI+roof line (RL) +left lateral isthmus line (LLI), and CPVI+complex fractional atrial electrogram (CFAE) ablation) at LA-CT image integrated in-silico AF modeling. We compared procedure related factors and clinical outcome between V-ABL and Em-ABL strategies.

Results: 1) In overall patients, pre-procedural computing time for 5 different ablation strategy was about 3 hours, and CPVI+PostBox+AntL most commonly showed the earliest termination rate (52.8%). 2) Among Em-ABL group, the earliest terminating in-silico ablation strategy match with empirical ablation in 21.9%. 3) V-ABL was not inferior to Em-ABL in terms of procedure time (256.2+69.0 vs. 271.5 +104.7 minutes, p=0.403), ablation time (4,954.7 + 2,804.0 vs. 5,272.8 + 2,368.2 seconds, p=0.510), and major complication rate (4.4% vs. 4.0%, p=0.900). 4) During 12.6+3.8 months follow-up, clinical recurrence rate after 3 month of ablation were 14.0% in V-ABL group and 18.9% in Emp-ABL group (p=0.538). 5) After excluding the patients matching the best virtual ablation strategy and empirical ablation strategy ir Emp-ABL group, clinical recurrence rates were 14.0% in V-ABL group and 22.0% in Emp-ABL group, respectively (p=0.355).

Conclusions: V-ABL was feasible in clinical practice with non-inferiority to Em-ABL in terms of procedure time, ablation time, complication rate, and short-term clinical recurrence rate in patients with PeAF.

THE FIRE AND ICE TRIAL: IMPACT OF CATHETER ABLATION TECHNOLOGIES ON PATIENT DEMOGRAPHIC-BASED CLINICAL OUTCOME AND HEALTHCARE COSTS

Karl-Heinz Kuck1, Josep Brugada2, Claudio Tondo3, Jean-Paul Albenque4

Asklepios Klinik St. Georg, Hamburg, Germany; 2Hospital Clinic; Barcelona, Spain; 3Centro Cardiologico Monzino, Milan, Italy; Clinique Pasteur Toulouse, France

Introduction: In the largest multicenter, multinational, randomized trial of catheter ablation for atrial fibrillation, we compared clinical outcomes after subgroup analyses by baseline patient demographics and examined costs associated with catheter ablation by either cryoballoon or radiofrequency current (RFC) technology

Methods: Regression models were used to examine the association between baseline patient demographics and cardiovascular (CV) re-hospitalizations, including the evaluation of patient cohorts that respond more favorable to either catheter technology. Also, a tnal-basec economic analysis of healthcare costs was conducted from the payer perspective. Analyses were based on rehospitalizations during the trial, with unit costs based on national tariffs (Germany €, UK £, and US $). Total healthcare costs were calculated and differences were analyzed using non-parametric methods.

Results: Subjects (N = 750) were randomized 1:1 to cryoballoon or RFC ablation (max follow-up=3 years; mean=1.5 years). Significant baseline demographics associated with CV rehospitalizations were age, BMI, CHA2DS2-VASc score, sex, HATCH score, hypertension, DC cardioversion, and systolic BP. Cryoballoon treated patients had a lower CV rehospitalization rate (p<0.001) and significantly lower thar RFC patients in the following subgroups: CHA2DS2-VASc score 0-1 (p=0.01), no heart failure (p=0.07), and prior DC cardioversion (p=0.01). No subgroup analysis favored RFC therapy. The differences in mean total costs of healthcare (per patient) during follow-up were €640, £364, and $925 in favor of the cryoballoon group (p=0.012, 0.013, and 0.016, respectively).

Conclusions: There were demographic characteristics that favored a reduction in CV rehospitalizations for the cryoballoon group, and an economic analysis demonstrated a reduction in costs that persisted across multiple healthcare systems. These important clinical and economic implications should be considered in clinical practice and by health technology assessments.

LBT 1-03

RIVAROXABAN FOR TREATMENT OF LEFT VENTRICLE THROMBOSIS

Monirah ALbabtain1, Yahya ALhebaishi1, Adel Othman1, Ola Al-Yafi2, Hatim Kheirallah1, Ahmed ALfagih1

Prince Sultan Cardiac Center; Riyadh, Saudi Arabia; Al Maarefa Colleges, Riyadh, Saudi Arabia

Introduction: The presence of thrombus in the left ventricle indicates anticoagulation for the potential life threatening of embolic complications, Vitamin K antagonists were the anticoagulants of choice. With the release of new oral anticoagulants (NOAC) and their advantages over vitamin K antagonists, the NOAC have replaced the warfarin in many indications. Rivaroxaban is approved for the prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation (AF), as well as prevention and treatment of venous throm-boembolism.

Methods: N/A.

Results: Ten adult patients (^ 18 years old) were reported by the echocardiography to have LV thrombus in 2016 at PSMMC cardiac center. The 9 patients have documented congestive heart failure with systolic dysfunction and normal lab parameters. Four of patients' have diabetes mellitus, five have hypertension and two have diastolic dysfunction. Patients were initiated on Rivaroxaban with the absence of any contraindications. Response to rivaroxaban was monitored by serial ECHOs at 2, 4, 8 and 12 weeks of Rivaroxaban initiation. In addition the Treatment safety monitored by periodic follow up CBCs & U/E, any signs of bleeding, hemoglobin and INR at clinical visits. Following the initiation of Rivaroxaban the LV thrombus sizes have been reduced for all patients; and have disappeared in 7 patients, without any reporting of bleeding or side effects. Only one Patient had ischemic stroke because of missing some doses of rivaroxaban for a penoc of two weeks, which has been confirmed by the pharmacy records of patients' medication refill.

Discussion and Conclusions: A case report described the growth of a left atrial appendage thrombus despite well-conducted treatment with a VKA, which then disappeared during treatment with rivaroxaban 15 mg/d. Another recent Japanese team published three cases of left atrial appendage thrombus resolution using rivaroxaban 10 mg/d. To the best of our knowledge the current case series is the first including 9 patients have successful reduction of LV thrombus and complete dissolution in 6 patients with rivaroxaban in relatively short time compared to VKA.

VENTRICULAR TACHYCARDIA & VENTRICULAR FIBRILLATION

LBT 1-04

ABSENCE OF REGIONAL FIBROSIS ON CARDIAC MRI IN VENTRICULAR FIBRILLATION AND NON-ISCHEMIC CARDIOMYOPATHY

Aleksandr Voskoboinik1, Michael Wong2, Jessica Elliott3, Ben Costello3, Sandeep Prabhu1, Jonathan Kalman4, Peter Kistler5, Andrew Taylor5, Joseph Morton4

'Alfred & Royal Melbourne Hospitals, Baker IDI, Melbourne, Australia; Western Health /Eastern Health, Melbourne, Australia; Alfred Hospital, Melbourne, Australia;4Royal Melbourne Hospital, Melbourne, Australia; Alfred Hospital & Baker IDI, Melbourne, Australia

Introduction: The majority of patients with non-ischemic cardiomyopathy (NICM) do not have macroscopic scar at autopsy. Presence of CMR-identified late gadolinium enhancement (LGE), representing regional fibrosis, can predict sustained monomorphic VT (SMVT) on ICD follow-up. We characterised CMR findings of ventricular LGE in cardiac arrest (CA) survivors with ventricular fibrillation (VF).

Methods: We examined consecutive VF patients with resuscitated CA undergoing contrast-enhanced 1.5-T CMR between 9/2007-7/2016. We excluded SMW, hypertrophic cardiomyopathy, amyloid/sarcoid, ARVC, channelopathy coronary artery disease. VF patients were divided into three groups: (i) NICM, (ii) LV dilatation with normal LVEF, (iii) Normal LV size and LVEF. Two control groups of NICM patients with and without SMVT were also examined.

Results: We analysed 87 VF patients, and found that LGE was seen in 8/22 (36%) with NICM (LVEF 38 + 11%, LVEDVI 134 + 68 mL/BSA), 11/40 (28%) with LV dilatation and normal LVEF (LVEDVI 103 + 17 mL/BSA), 4/25 (16%) with normal LV size and LVEF. The incidence of LGE in all VF groups was less than both control groups (p<0.01), with 117/277 (42%) NICM patients without prior VT/VF (LVEF 36+12%, LVEDVI 141 +46 mL/BSA) and 22/37 (59%) NICM patients with SMVT (LVEF 42+11%, LVEDVI 123+48 mL/BSA) being LGE-positive.

Conclusions: The majority of patients presenting with VF do not have LGE on CMR, including those with NICM and LV dilatation. Most failed to meet primary prevention ICD criteria based on LVEF. While LGE predicts increased risk of ventricular arrhythmias (esp. SMVT), its absence does not signify a low risk of VF. Novel risk-stratfiication tools are needed in NICM.