The DAVID (Dual Chamber and VVI Implantable Defibrillator) II trial.
OBJECTIVE
The purpose of this study was to determine whether atrial pacing is a safe alternative to minimal (backup-only) ventricular pacing in defibrillator recipients with impaired ventricular function.


BACKGROUND
The DAVID (Dual Chamber and VVI Implantable Defibrillator) trial demonstrated that dual chamber rate responsive pacing as compared with ventricular backup-only pacing worsens the combined end point of mortality and heart failure hospitalization. Although altered ventricular activation from right ventricular pacing was presumed to be the likely cause for these maladaptive effects, this supposition is unproven.


METHODS
In all, 600 patients with impaired ventricular function from 29 North American sites, who required an implanted defibrillator for primary or secondary prevention, with no clinical indication for pacing, were randomly assigned to atrial pacing (at 70 beats/min) versus minimal ventricular pacing (at 40 beats/min) and followed up for a mean of 2.7 years.


RESULTS
There were no significant differences between pacing arms in patients' baseline characteristics, use of heart failure medications, and combined primary end point of time to death or heart failure hospitalization during follow-up, with an overall incidence of 11.1%, 16.9%, and 24.6% at 1, 2, and 3 years, respectively. Similarly, the incidence of atrial fibrillation, syncope, appropriate or inappropriate shocks, and quality of life measures did not significantly differ between treatment groups.


CONCLUSIONS
The effect of atrial pacing on event-free survival and quality of life was not substantially worse than, and was likely equivalent to, backup-only ventricular pacing. Atrial pacing may be considered a "safe alternative" when pacing is desired in defibrillator recipients, but affords no clear advantage or disadvantage over a ventricular pacing mode that minimizes pacing altogether. (Dual Chamber and VVI Implantable Defibrillator [DAVID] Trial II; NCT00187187).
Wilkoff
Bruce L
BL
Cleveland Clinic, Cleveland, Ohio, USA.
Kudenchuk
Peter J
PJ
Buxton
Alfred E
AE
Sharma
Arjun
A
Cook
James R
JR
Bhandari
Anil K
AK
Biehl
Michael
M
Tomassoni
Gery
G
Leonen
Anna
A
Klevan
Linette R
LR
Hallstrom
Alfred P
AP
D000368:Aged; D001281:Atrial Fibrillation / Q000453:epidemiology / Q000209:etiology; D001919:Bradycardia / Q000209:etiology / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D002317:Cardiovascular Agents / Q000627:therapeutic use; D003131:Combined Modality Therapy; D017147:Defibrillators, Implantable / Q000009:adverse effects; D004554:Electric Countershock; D005260:Female; D006333:Heart Failure / Q000188:drug therapy / Q000401:mortality / Q000628:therapy*; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D011788:Quality of Life; D018487:Ventricular Dysfunction, Left / Q000188:drug therapy / Q000401:mortality / Q000628:therapy*
D002317:Cardiovascular Agents