Cardiac-resynchronization therapy for the prevention of heart-failure events.
BACKGROUND
This trial was designed to determine whether cardiac-resynchronization therapy (CRT) with biventricular pacing would reduce the risk of death or heart-failure events in patients with mild cardiac symptoms, a reduced ejection fraction, and a wide QRS complex.


METHODS
During a 4.5-year period, we enrolled and followed 1820 patients with ischemic or nonischemic cardiomyopathy, an ejection fraction of 30% or less, a QRS duration of 130 msec or more, and New York Heart Association class I or II symptoms. Patients were randomly assigned in a 3:2 ratio to receive CRT plus an implantable cardioverter-defibrillator (ICD) (1089 patients) or an ICD alone (731 patients). The primary end point was death from any cause or a nonfatal heart-failure event (whichever came first). Heart-failure events were diagnosed by physicians who were aware of the treatment assignments, but they were adjudicated by a committee that was unaware of assignments.


RESULTS
During an average follow-up of 2.4 years, the primary end point occurred in 187 of 1089 patients in the CRT-ICD group (17.2%) and 185 of 731 patients in the ICD-only group (25.3%) (hazard ratio in the CRT-ICD group, 0.66; 95% confidence interval [CI], 0.52 to 0.84; P=0.001). The benefit did not differ significantly between patients with ischemic cardiomyopathy and those with nonischemic cardiomyopathy. The superiority of CRT was driven by a 41% reduction in the risk of heart-failure events, a finding that was evident primarily in a prespecified subgroup of patients with a QRS duration of 150 msec or more. CRT was associated with a significant reduction in left ventricular volumes and improvement in the ejection fraction. There was no significant difference between the two groups in the overall risk of death, with a 3% annual mortality rate in each treatment group. Serious adverse events were infrequent in the two groups.


CONCLUSIONS
CRT combined with ICD decreased the risk of heart-failure events in relatively asymptomatic patients with a low ejection fraction and wide QRS complex. (ClinicalTrials.gov number, NCT00180271.)
Moss
Arthur J
AJ
Department of Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA. heartajm@heart.rochester.edu
Hall
W Jackson
WJ
Cannom
David S
DS
Klein
Helmut
H
Brown
Mary W
MW
Daubert
James P
JP
Estes
N A Mark
NA
Foster
Elyse
E
Greenberg
Henry
H
Higgins
Steven L
SL
Pfeffer
Marc A
MA
Solomon
Scott D
SD
Wilber
David
D
Zareba
Wojciech
W
D000368:Aged; D002304:Cardiac Pacing, Artificial; D017147:Defibrillators, Implantable; D018572:Disease-Free Survival; D004554:Electric Countershock; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000401:mortality / Q000628:therapy*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D013318:Stroke Volume