Context 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.
Data Sources 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.
Study Selection 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.
Data Extraction Trial reports were reviewed independently by 2 investigators in an unblinded
Data Synthesis 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