The impact of nonsustained ventricular tachycardia on reverse remodeling, heart failure, and treated ventricular tachyarrhythmias in MADIT-CRT.

INTRODUCTION: This study determined whether the presence of nonsustained ventricular tachycardia (NSVT) was predictive of clinical events in MADIT-CRT (multicenter automatic defibrillator implantation trial-cardiac resynchronization therapy) patients treated with CRT-defibrillator.

METHODS AND RESULTS: We analyzed 24-hour Holters for the presence of NSVT. Patients were then stratified by the etiology (ischemic or nonischemic) of cardiomyopathy. The impact of NSVT on heart failure events (HF), implantable cardioverter-defibrillator (ICD) therapy for rapid ventricular tachycardia (VT) or fibrillation (VF), and reverse remodeling was determined. At least a single episode of NSVT was recorded in 483 (49%) patients. These patients had a higher burden of premature ventricular contractions, lower percentage of biventricular (BiV) pacing, and significantly less reduction in left ventricular end-diastolic and end-systolic volumes. The risk of HF was significantly greater in patients with nonischemic cardiomyopathy and NSVT (hazard ratio [HR] 2.89; 95% confidence interval [CI]: 1.49-5.61; P = 0.002). The risk of rapid VT/VF was significantly greater (in both ischemic and nonischemic patients) when NSVT was observed (HR 2.06; 95% CI: 1.30-3.26; P = 0.002 in ischemic patients; HR 3.09; 95% CI: 1.80-5.28; P < 0.001 in nonischemic patients).

CONCLUSIONS: MADIT-CRT patients with NSVT had a high burden of ventricular ectopy, lower percentage of BiV pacing, and less reverse remodeling. These patients had an increase in HF (in nonischemic cardiomyopathy patients) and rapid VT/VF ICD therapies (in ischemic and nonischemic patients). These findings may have implications for the management of nonsustained ventricular ectopy in CRT patients.