Cardiac resynchronization and death from progressive heart failure: a meta-analysis of randomized controlled trials.
BACKGROUND
Progressive heart failure is the most common mechanism of death among patients with advanced heart failure. Cardiac resynchronization, a pacemaker-based therapy for heart failure, enhances cardiac performance and quality of life, but its effect on mortality is uncertain.


OBJECTIVE
To determine whether cardiac resynchronization reduces mortality from progressive heart failure.


METHODS
MEDLINE (1966-2002), EMBASE (1980-2002), the Cochrane Controlled Trials Register (Second Quarter, 2002), The National Institutes of Health ClinicalTrials.gov database, the US Food and Drug Administration Web site, and reports presented at scientific meetings (1994-2002). Search terms included pacemaker, pacing, heart failure, dual-site, multisite, biventricular, resynchronization, and left ventricular preexcitation.


METHODS
Eligible studies were randomized controlled trials of cardiac resynchronization for the treatment of chronic symptomatic left ventricular dysfunction. Eligible studies reported death, hospitalization for heart failure, or ventricular arrhythmia as outcomes. Of the 6883 potentially relevant reports initially identified, 11 reports of 4 randomized trials with 1634 total patients were included in the meta-analysis.


METHODS
Trial reports were reviewed independently by 2 investigators in an unblinded standardized manner.


RESULTS
Follow-up in the included trials ranged from 3 to 6 months. Pooled data from the 4 selected studies showed that cardiac resynchronization reduced death from progressive heart failure by 51% relative to controls (odds ratio [OR], 0.49; 95% confidence interval [CI], 0.25-0.93). Progressive heart failure mortality was 1.7% for cardiac resynchronization patients and 3.5% for controls. Cardiac resynchronization also reduced heart failure hospitalization by 29% (OR, 0.71; 95% CI, 0.53-0.96) and showed a trend toward reducing all-cause mortality (OR, 0.77; 95% CI, 0.51-1.18). Cardiac resynchronization was not associated with a statistically significant effect on non-heart failure mortality (OR, 1.15; 95% CI, 0.65-2.02). Among patients with implantable cardioverter defibrillators, cardiac resynchronization had no clear impact on ventricular tachycardia or ventricular fibrillation (OR, 0.92; 95% CI, 0.67-1.27).


CONCLUSIONS
Cardiac resynchronization reduces mortality from progressive heart failure in patients with symptomatic left ventricular dysfunction. This finding suggests that cardiac resynchronization may have a substantial impact on the most common mechanism of death among patients with advanced heart failure. Cardiac resynchronization also reduces heart failure hospitalization and shows a trend toward reducing all-cause mortality.
Bradley
David J
DJ
Division of Cardiology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Md, USA. DBradley@jhmi.edu
Bradley
Elizabeth A
EA
Baughman
Kenneth L
KL
Berger
Ronald D
RD
Calkins
Hugh
H
Goodman
Steven N
SN
Kass
David A
DA
Powe
Neil R
NR
D002304:Cardiac Pacing, Artificial; D017147:Defibrillators, Implantable; D006333:Heart Failure / Q000401:mortality / Q000628:therapy*; D006801:Humans; D010138:Pacemaker, Artificial; D016032:Randomized Controlled Trials as Topic; D016019:Survival Analysis; D018487:Ventricular Dysfunction, Left / Q000628:therapy