Should all patients receive dual chamber pacing ICDs? The rationale for the DAVID trial

Bruce L Wilkoff

doi:10.1186/cvm-2-5-215

Abstract

All of the prospective multicenter trials that support the use of implantable defibrillators have used single chamber pacemakers/implantable cardiovertor defibrillators (ICDs). Despite the significantly increased cost of dual chamber pacemaker/ICD devices and the lack of outcome data, these devices accounted for approximately two-thirds of the ICDs implanted in the United States during the 12 months ending April 2001. Dual chamber pacemaker trials have not provided data that would support this trend, but the high incidence of atrial fibrillation, bradycardia, and congestive heart failure, as comorbid conditions, suggest that the situation could be different in the defibrillator patient population. The DAVID (Dual Chamber and VVI Implantable Defibrillator) trial is designed to measure the incremental benefit of dual chamber pacemaker/ICDs.

Highlights

Dual chamber pacemaker/defibrillators combine pacemaker and implantable defibrillator technology
The results of multicenter, randomized clinical trials of atrial or dual chamber pacemakers compared to ventricular pacemakers have been sobering [1,2,3]
Are there reasons to believe that the addition of the atrial lead, rate responsive sensor, and dual chamber pacing modes, will help patients more than a single chamber ventricular pacemaker (VVI)/implantable cardiovertor defibrillators (ICDs)? Perhaps there are, but with the modest improvements observed in the pacemaker realm, it is incumbent on the electrophysiology community to measure the incremental benefit of the dual chamber rate-adaptive pacemaker (DDDR)/ICDs

Summary

DAVID trial protocol design

The DAVID trial is a US, multicenter, randomized comparison of dual chamber rate responsive pacemaker ICD therapy to ventricular pacing ICD therapy. It is administered by the Department of Biostatistics, University of Washington, WA, and is funded by a research grant from St Jude Medical (Sylmar, CA). DDDR = dual chamber rate adaptive pacemaker; EPS = electrophysiology study; ICD = implantable cardiovertor defibrillator; LVEF = left ventricular ejection fraction; VF = ventricular fibrillation; VT = ventricular tachycardia; VVI = single chamber ventricular pacemaker. Data from the AVID (Antiarrhythmics Vs Implantable Defibrillators) trial demonstrated that in a very similar patient population there was a 50% mortality rate within 2 years after a hospitalization for congestive heart failure. The primary comorbidity that affects mortality is congestive heart failure, so only patients with LVEF of 40% or less are included, and all patients are to be treated with beta-blockers, angiotensinconverting-enzyme inhibitors and other appropriate heart failure therapies

Contrasting pacemaker and ICD patients

Biventricular pacing

Findings

Conclusion