Prognostic significance of nonsustained ventricular tachycardia in patients receiving cardiac resynchronization therapy for primary prevention: Analysis of the Japan cardiac device treatment registry database

Background: Whether nonsustained ventricular tachycardia (NSVT) is a marker of increased risk of sustained ventricular tachyarrhythmias (VTAs) remains to be established in patients receiving cardiac resynchronization therapy with a defibrillator (CRT-D) for primary prevention. Methods: Among the follow-up data of the Japan cardiac device treatment registry (JCDTR) with an implantation date between January 2011 and August 2015, information regarding a history of NSVT before the CRT-D implantation for primary prevention had been registered in 269 patients. Outcomes were compared between two groups with and without NSVT: NSVT group (n = 179) and No NSVT group (n = 90). Results: There was no significant difference with regard to age, gender, and NYHA class between the two groups. Left ventricular ejection fraction (LVEF) was 25.6% in the NSVT group and 28.0% in the No NSVT group (P =.046). The rate of appropriate therapy at 24 months was 26.0% and 18.4% in the NSVT and No NSVT groups (P =.22), respectively. Survival free from heart failure death was reduced in the NSVT group, as compared with the No NSVT group, with the rate of 90.2% vs 97.2% at 24 months (P =.030). A multivariate analysis identified a history of NSVT, anemia, and no use of angiotensin-converting enzyme inhibitor (ACEI) or angiotensin- receptor blocker (ARB) as predictors of heart failure death. Conclusions: NSVT appears to be a surrogate marker of severe heart failure rather than a substrate for subsequent sustained VTAs in patients with CRT-D for primary prevention.