"Cardiac-Resynchronization Therapy for the Prevention of Heart-Failure Events".

The New England Journal of Medicine. 2009. 361(14):1329-1338.
PubMed•Full text•PDF

Contents

1 Clinical Question
2 Bottom Line
3 Major Points
4 Guidelines
5 Design
6 Population
6.1 Inclusion Criteria
6.2 Exclusion Criteria
6.3 Baseline Characteristics
7 Interventions
8 Outcomes
8.1 Primary Outcome
8.2 Secondary Outcomes
9 Funding
10 Further Reading

Clinical Question

Does cardiac-resynchronization therapy (CRT) with biventricular pacing reduce the risk of death or heart-failure events in patients with mild cardiac symptoms, a reduced ejection fraction, and a wide QRS complex?

Bottom Line

CRT combined with an implantable cardioverter–defibrillator (ICD) decreased the risk of heart-failure events in relatively asymptomatic patients with a low ejection fraction and wide QRS complex.

Major Points

Guidelines

The 2008 guidelines for implantation of cardiac devices recommend CRT as a class I indication for patients with a left ventricular ejection fraction of 35% or less, a QRS duration of 120 msec or more, and sinus rhythm who have NYHA functional class III or ambulatory class IV heart-failure symptoms.

Design

Multicenter, randomized, controlled trial
N=1,820
CRT-ICD (n=1,089)
ICD alone (n=731)
Setting: 110 hospital centers
Enrollment: 2004-2008
Mean follow-up: 2.4 years
Analysis: Intention-to-treat
Primary outcome: Death from any cause or a nonfatal heart-failure event

Population

Inclusion Criteria: NYHA class I (ischemic cardiomyopathy) or class II (ischemic or nonischemic cardiomyopathy), ejection fraction of ≤30%, QRS duration ≥130 msec, sinus rhythm.
Exclusion Criteria: Existing or planned CRT, recent MI or cardiac intervention, atrial fibrillation, and other criteria.
Baseline Characteristics: Similar across groups.

Interventions

Patients were randomly assigned to receive CRT with an ICD (CRT-ICD group) or an ICD alone (ICD-only group).

Outcomes

Primary Outcome: Risk reduction of 34% for death or nonfatal heart-failure events in the CRT-ICD group compared to the ICD-only group (hazard ratio, 0.66; 95% confidence interval, 0.52 to 0.84; P=0.001).
Secondary Outcomes: Significant reduction in left ventricular volumes and improvement in ejection fraction in the CRT-ICD group.

Funding

Supported by a research grant from Boston Scientific to the University of Rochester.

Further Reading

Full text available on the New England Journal of Medicine website.