Dual-Chamber Versus Single-Chamber Detection Enhancements for Implantable Defibrillator Rhythm Diagnosis

TLDR

Inappropriate ICD shocks from misdetection of supraventricular tachycardia remain a major complication, and it is uncertain whether optimally programmed dual‑chamber devices reduce this risk compared with single‑chamber ICDs. In a multicenter randomized trial of 400 ICD‑eligible patients, subjects received dual‑chamber ICDs and were assigned to strictly defined optimal single‑ or dual‑chamber detection with ventricular pacing minimized, with the primary endpoint being the proportion of SVT episodes inappropriately detected. Dual‑chamber detection lowered inappropriate SVT detection from 39.5% to 30.9%, halving the odds (OR 0.53, 95% CI 0.30–0.94, P = 0.03), while mortality and early withdrawal rates were comparable.

Abstract

Background— Delivery of inappropriate shocks caused by misdetection of supraventricular tachycardia (SVT) remains a substantial complication of implanted cardioverter/defibrillator (ICD) therapy. Whether use of optimally programmed dual-chamber ICDs lowers this risk compared with that in single-chamber ICDs is not clear. Methods and Results— Subjects with a clinical indication for ICD (n=400) at 27 participating centers received dual-chamber ICDs and were randomly assigned to strictly defined optimal single- or dual-chamber detection in a single-blind manner. Programming minimized ventricular pacing. The primary end point was the proportion of SVT episodes inappropriately detected from the time of programming until crossover or end of study. On a per-episode basis, 42% of the episodes in the single-chamber arm and 69% of the episodes in the dual-chamber arm were due to SVT. Mortality (3.5% in both groups) and early study withdrawal (14% single-chamber, 11% dual-chamber) were similar in both groups. The rate of inappropriate detection of SVT was 39.5% in the single-chamber detection arm compared with 30.9% in the dual-chamber arm. The odds of inappropriate detection were decreased by almost half with the use of the dual-chamber detection enhancements (odds ratio, 0.53; 95% confidence interval, 0.30 to 0.94; P =0.03). Conclusions— Dual-chamber ICDs, programmed to optimize detection enhancements and to minimize ventricular pacing, significantly decrease inappropriate detection.