Abstract 13917: Predictors of Ventricular Arrhythmias in Patients With Left Ventricular Ejection Fraction Improvement to >35% Following Cardiac Resynchronization Therapy

Abstract

Introduction: Patients undergoing cardiac resynchronization therapy with a defibrillator (CRT-D) show significant improvement in LVEF. We designed this study to identify predictors of ventricular arrhythmic (VA) events among patient with LVEF improvement > 35% after one year of treatment with CRT-D. Hypothesis: We hypothesized that LVEF improvement > 35% is associated with a decreased risk of VA events. Methods: Patients randomized to CRT-defibrillator from the Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy (MADIT-CRT) trial with LVEF > 35% at 12 months were included in this analysis (N=651). Predictors of an appropriate ICD therapy for VA subsequent to one year were evaluated by cox regression model. Cumulative probability of first event was analyzed by Kaplan Meier Method with time for follow-up beginning at 1 year after device implantation. Results: The average follow-up was 2.04 ± 0.83 years. We identified 3 independent predictors of VA among patients treated with CRT-D subsequent to LVEF improvement to > 35%: (1) baseline non-LBBB morphology (HR=1.93; 95% CI,1.23-3.04; p= 0.004); (2) the occurrence of VA during first year post CRT-D implant (HR=4.91 [95% CI, 2.99-8.07]; p<0.001); and (3) lower range improvement in LVEF (36-40% vs. >40%; HR =1.97 [95% CI 1.21-3.20]; p= 0.006). When compared with patients with 0 risk factors, having one and 2 or more risk factors had significantly higher risk of VTA (2-year rate of VT/VF = 4%, 11% and 32% respectively; HRs = 2.9 [p=0.002]and 7.9 [p=<0.001], respectively [Figure]). Conclusions: We identify a sub-group of patients who remain at high risk of VTA despite improvement in LVEF > 35% with CRT-D. Having a baseline non-LBBB morphology, experiencing VA during the first year post CRT-D, and lower-range LVEF improvement are associated with high risk of future arrhythmias, with a cumulative effect.