Dual Chamber and VVI Implantable Defibrillator II (DAVID II)

Anthony A. Bavry, MD, MPH; Deepak L. Bhatt, MD, FACC




The goal of the trial was to evaluate atrial pacing compared with minimal ventricular pacing (i.e., back-up pacing) among patients with reduced left ventricular (LV) function and no clinical indication for pacing who had received a defibrillator.


Atrial pacing would be a safe alternative to ventricular pacing.

Drugs/Procedures Used

Patients with impaired LV systolic function who had received a defibrillator and without indication for pacing were randomized to atrial pacing (AAI-70) (n = 300) versus minimal ventricular pacing (VVI-40) (n = 300).

Concomitant Medications

There was no difference in medications between treatment arms. The use of discharge medications in the minimal ventricular pacing group was: 88% for angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker, 90% for beta-blocker, 57% for diuretic, 27% for digoxin, 18% for spironolactone, 75% for statin, and 17% for antiarrhythmic medication.

Principal Findings

Overall, 600 patients were randomized. There was no difference in baseline characteristics between treatment arms. In the VVI-40 group, the mean age was 63 years, 15% were women, mean LV ejection fraction was 27%, and ischemic cardiomyopathy was present in 93%.

There was no difference between the groups with respect to the primary endpoint, time to death, or heart failure hospitalization (24.6% for both groups, p = 0.95). There was no difference in the primary outcome among any of the tested subgroups.

There was no difference in death (p = 0.81), heart failure hospitalization (p = 1.0), syncope (p = 0.64), atrial fibrillation (p = 0.61), or first hospitalization (p = 0.46). Quality of life was also similar between the groups.


Among patients with LV dysfunction who had received a defibrillator and did not have a primary indication for pacing, the use of atrial pacing at 70 bpm was similar to minimal ventricular pacing at 40 bpm. This was evident in regard to the primary outcome of time to death or heart failure hospitalization, as well as the secondary outcomes.

The initial DAVID trial demonstrated that dual-chamber pacing was inferior to minimal ventricular pacing (i.e., back-up). The hypothesis was that the act of pacing may not be harmful, but rather the mode of pacing may be culprit (i.e., constant ventricular pacing). In the current trial, according to the authors, when pacing is determined to be necessary in defibrillator patients, atrial pacing may be a "safe alternative" to minimal ventricular pacing, although there is no clear advantage or disadvantage from either strategy.


  • Arrhythmias / Ventricular fibrillation

  • Arrhythmias / Ventricular tachycardia

  • Arrhythmias / Atrial fibrillation

  • Heart failure / Ischemic


  • Implantable Cardioverter Defibrillator (ICD)

  • Pacing / VVI

  • Pacing

Study Design

Randomized. Blinded. Parallel.

Patients Enrolled: 600
NYHA Class (% I, II, II, IV): Class I, 46%; class II, 45%; class III, 10%
Mean Follow-Up: 2.7 years
Mean Patient Age: 63 years
% Female: 15%

Mean Ejection Fraction: 26%

Primary Endpoints

  • Time to death or heart failure hospitalization

Secondary Endpoints

  • All appropriate defibrillator therapies

  • All inappropriate defibrillator therapies

  • Quality of life measurements

Patient Population

One of the following criteria:

  • Enrollment in the DAVID trial without prior clinical trial endpoint

  • LV ejection fraction ≤ 40% and one of the following within the past 6 weeks: 1) prior cardiac arrest due to ventricular fibrillation or ventricular tachycardia, 2) ventricular tachycardia with syncope, and 3) ventricular tachycardia with symptoms of hypotension (systolic blood pressure < 80 mm Hg)

  • LV ejection fraction ≤ 40% and inducible ventricular fibrillation or ventricular tachycardia on electrophysiology study within the past 6 weeks

  • LV ejection fraction ≤ 30% due to coronary artery disease and at least 1 month from myocardial infarction or 3 months from coronary revascularization


  • Permanent pacemaker

  • Symptomatic bradycardia, prolonged PR interval, or greater than first-degree heart block

  • Atrial fibrillation longer than 6 months

  • Frequent supraventricular tachycardia

  • New York Heart Association (NYHA) class IV or NYHA III with less than 3 months of optimal therapy

  • Awaiting heart transplantation

  • Prisoner

  • Unable to give informed consent

  • Life expectancy < 1 year


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