Cardiac resynchronization therapy effective in less symptomatic heart failure

Cardiac resynchronization therapy (CRT) can benefit patients with less symptomatic heart failure, a new meta-analysis indicates.

The study researchers had previously found that CRT reduces morbidity and mortality in patients with symptoms of advanced heart failure. In the current study, they updated their earlier review to examine the effects of CRT in patients whose heart failure was less symptomatic. They performed a literature search from 1950 to December 2010 of studies in all languages and selected randomized, controlled trials comparing CRT with usual care and right or left ventricular pacing in adult patients with heart failure whose left ventricular ejection fraction was 0.40 or less. The primary study endpoint was all-cause mortality; however, researchers also examined heart failure hospitalizations, quality of life, and functional outcomes. The study results were published online Feb. 15 by Annals of Internal Medicine.

Data from 25 trials including 9,082 patients were analyzed. CRT decreased all-cause mortality (risk ratio, 0.83; 95% CI, 0.72 to 0.96) and hospitalizations for heart failure (risk ratio, 0.71; 95% CI, 0.57 to 0.87) among patients with New York Heart Association (NYHA) class I and II symptoms, but did not improve functional outcomes or quality of life. CRT did improve functional outcomes in patients with NYHA class III or IV symptoms while reducing all-cause mortality (risk ratio, 0.78; 95% CI, 0.67 to 0.91) and heart failure hospitalizations (risk ratio, 0.65; 95% CI, 0.50 to 0.86).

The authors noted that their study's subgroup analyses were underpowered and did not include sufficient data for patients who had NYHA class I symptoms, chronic kidney disease, bradyarrhythmias, atrial fibrillation, or right bundle-branch block. However, they concluded that CRT was effective in patients with reduced left ventricular ejection fraction, heart failure symptoms and prolonged QRS duration, regardless of their NYHA class. “Establishing criteria for case selection so that CRT devices are preferentially implanted in the patients who are most likely to benefit is of vital importance for researchers, clinicians, and policymakers,” the authors wrote.