Predictors of Sustained Ventricular Arrhythmias in Cardiac Resynchronization Therapy

Abstract

Background: Patients undergoing cardiac resynchronization therapy (CRT) are at high risk for ventricular arrhythmias and risk stratification in this population remains poor. Methods and Results: This study followed 269 patients (LVEF < 35%, QRS > 120ms, NYHA III/IV) undergoing CRT with defibrillator (CRT-D) for 553±464 days after CRT-D implantation to assess for independent predictors of appropriate device therapy for ventricular arrhythmias (VAs). Baseline medication use, medical comorbidities, and echocardiographic parameters were considered. The 4-year incidence of appropriate device therapy was 36%. A Cox proportional hazard model identified left ventricular end systolic diameter (LVESD) > 61mm as an independent predictor in the entire population (HR 2.66, p = 0.001). Those with LVESD > 61mm had a 51% 3-year incidence of VA compared to a 26% incidence among those with a less dilated ventricle (p = 0.001). Among patients with LVESD ≤61mm, multivariate predictors of appropriate therapy were absence of beta-blocker therapy (HR 6.34, p<0.001, LVEF < 20% (HR 4.22, p <0.001), and history of sustained VA (2.97, p = 0.013). Early (<180d after implant) shock therapy was found to be a robust predictor of heart failure hospitalization (HR 3.41, p < 0.004) and mortality (HR 5.16 p < 0.001.) Conclusions: Among CRT-D patients, LVESD > 61mm is powerful predictor of ventricular arrhythmias and further risk stratification of those with less dilated ventricles can be achieved based on assessment of EF, history of sustained VA, and absence of beta-blocker therapy.