Dual-Chamber Pacing or Ventricular Backup Pacing in Patients With an Implantable Defibrillator

TLDR

ICD therapy with backup ventricular pacing improves survival in patients with life‑threatening ventricular arrhythmias, yet most ICDs provide dual‑chamber pacing. This study aimed to evaluate whether dual‑chamber pacing offers a clinical benefit over ventricular backup pacing in ICD patients without a pacing indication. In the DAVID trial, 506 patients with LVEF ≤ 40 % and no pacing indication were randomized to ICDs programmed for VVI‑40 or DDDR‑70 and followed for one year. VVI‑40 programming resulted in a higher one‑year survival free of death or heart‑failure hospitalization (83.9 % vs 73.3 %) and lower mortality and HF admissions, indicating dual‑chamber pacing provides no advantage and may be detrimental.

Abstract

ContextImplantable cardioverter defibrillator (ICD) therapy with backup ventricular pacing increases survival in patients with life-threatening ventricular arrhythmias. Most currently implanted ICD devices provide dual-chamber pacing therapy. The most common comorbid cause for mortality in this population is congestive heart failure.ObjectiveTo determine the efficacy of dual-chamber pacing compared with backup ventricular pacing in patients with standard indications for ICD implantation but without indications for antibradycardia pacing.DesignThe Dual Chamber and VVI Implantable Defibrillator (DAVID) Trial, a single-blind, parallel-group, randomized clinical trial.Setting and ParticipantsA total of 506 patients with indications for ICD therapy were enrolled between October 2000 and September 2002 at 37 US centers. All patients had a left ventricular ejection fraction (LVEF) of 40% or less, no indication for antibradycardia pacemaker therapy, and no persistent atrial arrhythmias.InterventionsAll patients had an ICD with dual-chamber, rate-responsive pacing capability implanted. Patients were randomly assigned to have the ICDs programmed to ventricular backup pacing at 40/min (VVI-40; n = 256) or dual-chamber rate-responsive pacing at 70/min (DDDR-70; n = 250). Maximal tolerated medical therapy for left ventricular dysfunction, including angiotensin-converting enzyme inhibitors and β-blockers, was prescribed to all patients.Main Outcome MeasureComposite end point of time to death or first hospitalization for congestive heart failure.ResultsOne-year survival free of the composite end point was 83.9% for patients treated with VVI-40 compared with 73.3% for patients treated with DDDR-70 (relative hazard, 1.61; 95% confidence interval [CI], 1.06-2.44). The components of the composite end point, mortality of 6.5% for VVI-40 vs 10.1% for DDDR-70 (relative hazard, 1.61; 95% CI, 0.84-3.09) and hospitalization for congestive heart failure of 13.3% for VVI-40 vs 22.6% for DDDR-70 (relative hazard, 1.54; 95% CI, 0.97-2.46), also trended in favor of VVI-40 programming.ConclusionFor patients with standard indications for ICD therapy, no indication for cardiac pacing, and an LVEF of 40% or less, dual-chamber pacing offers no clinical advantage over ventricular backup pacing and may be detrimental by increasing the combined end point of death or hospitalization for heart failure.