Reverse remodeling and the risk of ventricular tachyarrhythmias in the MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy).

Objective: We aimed to evaluate the relationship between echocardiographic response to cardiac resynchronization therapy (CRT) and the risk of subsequent ventricular tachyarrhythmias (VTAs).

Background: Current data regarding the effect of CRT on the risk of VTA are limited and conflicting.

Methods: The risk of a first appropriate implantable cardioverter-defibrillator (ICD) therapy for VTA (including ventricular tachycardia, ventricular fibrillation, and ventricular flutter) was compared between high- and low-echocardiographic responders to CRT defibrillator (CRT-D) therapy (defined as ≥ 25% and <25% reductions, respectively, in left ventricular end-systolic volume [LVESV] at 1 year compared with baseline) and ICD-only patients enrolled in the MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy).

Results: The cumulative probability of a first VTA at 2 years after assessment of echocardiographic response was highest among low responders to CRT-D (28%), intermediate among ICD-only patients (21%), and lowest among high responders to CRT-D (12%), with p < 0.001 for the overall difference during follow-up. Multivariate analysis showed that high responders to CRT-D experienced a significant 55% reduction in the risk of VTA compared with ICD-only patients (p < 0.001), whereas the risk of VTA was not significantly different between low responders and ICD-only patients (hazard ratio [HR]: 1.26; p = 0.21). Consistently, assessment of response to CRT-D as a continuous measure showed that incremental 10% reductions in left ventricular end-systolic volume were associated with corresponding reductions in the risk of subsequent VTA (HR: 0.80; p < 0.001), VTA/death (HR: 0.79; p < 0.001), ventricular tachycardia (HR: 0.80; p < 0.001), and ventricular fibrillation/ventricular flutter (HR: 0.75; p = 0.044).

Conclusions: In patients with left ventricular dysfunction enrolled in the MADIT-CRT trial, reverse remodeling was associated with a significant reduction in the risk of subsequent life-threatening VTAs. (Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy [MADIT-CRT]; NCT00180271).