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5, May Supplement 2017. C-MP01- ... Thursday, May 11, 2017. 9:30 AM - 10:30 AM. C-MP01- ... prevalence and manifestation of sudden cardiac death (SCD).
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Heart Rhythm, Vol. 14, No. 5, May Supplement 2017

MODERATED POSTER C-MP01: Best of Early Career Physician Abstracts Thursday, May 11, 2017 9:30 AM - 10:30 AM

C-MP01-01 SERCA2A GENE THERAPY SUPPRESSES POST-MI ARRHYTHMIAS BY INCREASING CONDUCTION RESERVE VIA A CAMKII DEPENDENT PATHWAY Lukas J. Motloch, MD, PhD. Mount sinai school of medicine, New york city, NY

Background: When delivered at the time of an insult, SERCA2a gene therapy (GT) hinders disease progression. Whether SERCA2a GT reverses preestablished electrophysiological (EP) remodeling at an advanced disease stage is unclear. Objective: To uncover the EP effects of AAV9 SERCA2a GT following myocardial infarction (MI) and determine underlying mechanisms. Methods: Yorkshire pigs developed mechanical dysfunction 1 mo following anterior MI, at which point they received intracoronary AAV1 SERCA2a (MI+SERCA2a) or saline (MI) and were maintained for 2 mo. In vivo EP and hemodynamic properties were assessed before sacrifice. The EP substrate was measured using optical action potential (AP) mapping in ex vivo perfused preparations from MI+SERCA2a (N=5), MI (N=5) and Sham (N=8) pigs. Results: QT and QTc intervals were comparable between groups (p=NS). Prolonged QRS duration (p=0.019) and increased frequency of R’ waves (p=.046) in MI were reversed by SERCA2a GT which also delayed dobutamine induced proarrhythmia. MI (4/5) but not MI+SERCA2a (1/5) or Sham (0/8) hearts were prone to pacing induced VT. Underlying these arrhythmias was pronounced conduction velocity (CV) slowing in MI compared to MI+SERCA2a at elevated rates leading to VT (Fig). Preserved CV in MI+SERCA2a was not related to hemodynamic function. Rather, SERCA2a GT reversed profibrotic gene expression and decreased phosphoactive but not total CAMKII levels by >50% leading to improved excitability and preserved AP upstroke velocity at fast rates (Fig). Conclusion: SERCA2a GT suppresses post MI arrhythmias by increasing CV reserve via CAMKII. Our findings suggest a novel primary effect of SERCA2a GT on myocardial excitability.

C-MP01-02 ASYMPTOMATIC CEREBRAL EMBOLISM IN ABLATION WITH THE SECOND GENERATION PVAC GOLD Fehmi Keçe, MD. Leiden University Medical Center, Leiden, Netherlands

Background: AF ablation with the first generation duty-cycled non-irrigated radiofrequency catheter is associated with an increased incidence of asymptomatic cerebral embolism (ACE). A second generation catheter (PVAC Gold™) was designed to avoid this complication. Objective: To compare the incidence and clinical implications of ACE between the PVAC Gold catheter and an irrigated-tip catheter. Methods: Seventy pts (61±9 years, 43 male, CHADS2-VASc score 1.6±1.2) with paroxysmal AF were 1: 1 randomized to pulmonary vein isolation (PVI) with PVAC Gold™ or Thermocool™ (TC) catheter. Cerebral MRI with diffusionweighted, Fluid Attenuated Inversion Recovery and T2-weighted Turbo Spin sequences was performed on the day before and after ablation and 3 months thereafter if a new lesion developed. Continuous oral anticoagulation (INR≥2) and intravenous heparinization (ACT≥350s) were used. The PVAC catheter was submerged before introduction. During ablation, monitoring for detection of microembolic signals (MES) was performed by Transcranial Doppler Ultrasonography. Changes in coagulant state were determined with Prothrombin Time, Activated Partial Thromboplastin Time, INR, Von Willebrand antigen and fibrinogen before, during and after ablation. Neuropsychological tests and questionnaires tapping cognition and mood were applied 10 days before and 3 months after ablation. Results: No differences in baseline patient characteristics were found between groups, with a mean INR of 2.7±0.5 and ACT of 374±24. Procedural duration was shorter in the PVAC group (140±34 vs. 207±44 min, p2.56 was still confirmed as significant predictor for cardiovascular events (HR 7.69 [1.79; 33.33], p35yrs), of which 91 (26%) were women and 259 (74%) were men (2005-2010). Detailed clinical and autopsy data including cardiac and coronary gross and histopathology findings were compared between the groups.

Results: Age was not significantly different (women, 59.1 ± 16.5 yr vs. men, 57.6 ± 13.9 yr; p 0.19). Both genders had similar body mass index (women, 30.7 ± 7.9 kg/m2 vs. men, 29.3 ± 6.7; p=0.06). As expected, women had lower mean heart weight (432.6 ± 124 g vs. 543.9 ± 139 g; p35%, including in 75% of primary prevention patients with AppRx. In secondary prevention (2°) patients, a greater percentage (25%) of patients with EF>35% received ApprRx, compared to those with EF≤35% (7.1%). Alarmingly, 22.2% of 2° patients did not have an ICD at the time of their initial SCD event because they were disqualified due to EF recovery. Conclusion: In patients with CAD, the ICD provides sudden death protection even after EF improves to >35%. The practice of withholding ICD therapy for EF recovery to >35% was associated with sudden death events in this analysis, and requires reexamination.

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WITHHOLDING ICDS AFTER EF IMPROVES TO >35% CAN NOT BE JUSTIFIED IN ALL PATIENTS WITH CAD AND LEFT VENTRICULAR SYSTOLIC DYSFUNCTION (LVSD)

DOES CATHETER-BASED VENTRICULAR TACHYCARDIA ABLATION WORSEN HEART FAILURE OUTCOMES? FINDINGS FROM A PROPENSITY SCORE MATCHED ANALYSIS

Indrajit Choudhuri, MD, Kanwar Yugraj Singh, MD, Firas Zahwe, MD, Tadele Mangesha, MS, Robyn Shearer, MS, Crystal Platz, NP, Bilal Omery, MD, Arshad Jahangir, MD, M. Eyman Mortada, MD, Jasbir S. Sra, MD, FHRS and Masood Akhtar, MD, FHRS. Aurora Cardiovascular Services, Aurora Sinai/Aurora St. Luke’s Med Ctrs, University of Wisconsin School of Medicine and Public Health, Milwaukee, WI, Aurora Cardiovascular Services, Aurora Sinai/Aurora St. Luke’s Med Ctrs, Milwaukee, WI, Aurora Research Institute, Aurora Sinai/Aurora St. Luke’s Med Ctrs, Milwaukee, WI, Center for Integrative Research on CV Aging Aurora Health Care, Milwaukee, WI, Aurora Cardiovasc Svcs, Aurora Sinai/St. Luke’s Med Ctrs, Univ Wisconsin Sch Med & Public Health-MC, Milwaukee, WI, University of Wisconsin School of Medical and Public Health - Milwaukee Clin. Campus, Milwaukee, WI, Aurora Cardiovascular Services, Aurora Sinai/ Aurora St. Luke’s Medical Centers, University of Wisconsin School of Medicine and Public Health, Milwaukee, WI Background: When EF≤35% is identified, ICDs are considered for SCD protection, but are withheld if EF improves to >35% within 90 days. This practice is not supported by direct evidence and may leave a significant segment of the population exposed to SCD risk.

Andreu Porta-Sanchez, MD, Andrew CT. Ha, MD, Fahad Almehmadi, MD, FRCP, Xuesong Wang, MSc, Hadas Fischer, MD, MSc, Atif Al-Qubbany, MD, Diego Chemello, MD, Peter C. Austin, PhD, Sandra Nip, RN, Douglas S. Lee, MD, PhD and Kumaraswamy Nanthakumar, MD. Division of Cardiology. University Health Network., Toronto, ON, Canada, Toronto General Hospital, University Health Network, Toronto, ON, Canada, Institute for Clinical Evaluative Sciences, Toronto, ON, Canada, Institute for Clinical Evaluative Sciences (ICES), Toronto, ON, Canada, University Health Network - Toronto General Hospital, Toronto, ON, Canada

Background: The impact of catheter-based VT ablation on heart failure (HF) outcomes is not well defined in published studies. Theoretically, extensive ablation of diseased myocardium could subsequently worsen patients’ HF status. Alternatively, reduction of ventricular arrhythmia (VA) burden by ablation may prevent future HF events. Objective: To compare the rate of HF-related and VA-related hospitalization and emergency room (ER) visit between patients with VT who underwent ablation vs. medical therapy. Methods: From a single institution, 99 consecutive patients who underwent VT ablation were identified. The comparison

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Moderated Posters group consisted of 99 propensity-score matched patients who experienced appropriate ICD shocks for VT and had subsequent VT and were treated with medical therapy only. This cohort was derived from a prospective database of ≈7,000 ICD patients in Ontario, Canada. Using Cox proportional hazard modelling, the following outcomes were compared between the 2 groups: HF hospitalization, ER visit due to HF, and hospitalization or ER visit due to VA. Using a Poisson regression model, we compared the rates of HF or VA hospitalization before and after the index procedure for patients in the VT ablation cohort. Results: The rate of HF hospitalization (HR 0.61, 95% CI 0.3-1.24), ER visit due to HF (HR 0.95, 95% CI 0.47-1.93), hospitalization due to VA (HR 1.13 95% CI 0.6-2.1), and ER visit due to VA (HR 0.89 95%CI 0.45-1.73, p=ns for all) were similar between patients treated with VT ablation or medical therapy. Amongst patients who underwent VT ablation, their rates of HFrelated hospitalization were similar in the 1 year before and after their index ablation procedure (Event rate ratio (ERR) 1.05, 95% CI, 0.54-2.05, p=NS). On the other hand, the rates of VA-related hospitalizations and ER visits were lower within the 12 months after ablation when compared to the preceding 12 months preablation (ERR 0.45, 95% CI 0.32-0.63, p