posted on 2009-12-08, 16:25authored byW. D. Toff, A. J. Camm, J. D. Skehan, United Kingdom Pacing and Cardiovascular Events Trial Investigators.
background
In the treatment of atrioventricular block, dual-chamber cardiac pacing is thought to
confer a clinical benefit as compared with single-chamber ventricular pacing, but the
supporting evidence is mainly from retrospective studies. Uncertainty persists regarding
the true benefits of dual-chamber pacing, particularly in the elderly, in whom it is
used less often than in younger patients.
methods
In a multicenter, randomized, parallel-group trial, 2021 patients 70 years of age or
older who were undergoing their first pacemaker implant for high-grade atrioventricular
block were randomly assigned to receive a single-chamber ventricular pacemaker
(1009 patients) or a dual-chamber pacemaker (1012 patients). In the singlechamber
group, patients were randomly assigned to receive either fixed-rate pacing
(504 patients) or rate-adaptive pacing (505 patients). The primary outcome was death
from all causes. Secondary outcomes included atrial fibrillation, heart failure, and a composite
of stroke, transient ischemic attack, or other thromboembolism.
results
The median follow-up period was 4.6 years for mortality and 3 years for other cardiovascular
events. The mean annual mortality rate was 7.2 percent in the single-chamber
group and 7.4 percent in the dual-chamber group (hazard ratio, 0.96; 95 percent confidence
interval, 0.83 to 1.11). We found no significant differences between the group
with single-chamber pacing and that with dual-chamber pacing in the rates of atrial
fibrillation, heart failure, or a composite of stroke, transient ischemic attack, or other
thromboembolism.
conclusions
In elderly patients with high-grade atrioventricular block, the pacing mode does not
influence the rate of death from all causes during the first five years or the incidence of
cardiovascular events during the first three years after implantation of a pacemaker.
History
Citation
New England Journal of Medicine, 2005, 353 (2), pp.145-155