Comparison of CRT and CRT-D in heart failure: systematic review of controlled trials.

Background: Few studies have directly compared cardiac resynchronisation therapy (CRT) with combined CRT-cardioverter defibrillator therapy (CRT-D) in patients with left ventricular (LV) impairment. We performed a systematic analysis to assess the therapeutic effects of CRT and CRT-D in patients with LV impairment and heart failure.

Methods: The Medline database from 1970 to September 2010 was searched. The major outcome examined was the all-cause death rate.

Results: A total of 3404 patients were retrieved from seven studies. Overall, CRT-D reduced all-cause death by 8.42% compared with CRT [odds ratio (OR) 0.52, 95% confidence interval (CI) 0.43-0.81, P=0.001, I(2)=63.9%]. An increased benefit was seen after extended follow-up (after 1 year, OR 0.56, CI 0.41-0.77, P=0.0004, I(2)=64.9%), but not after relatively short follow-up (within 1 year, P=0.11). Results from other endpoints examined, such as death from sudden cardiac death and heart failure, also supported CRT-D treatment.

Conclusions: Evidence from current randomised and non-randomised trials demonstrates some superiorities of CRT-D over CRT, such as all-cause death rate after one-year follow-up and cardiac death, in patients with LV impairment. However, these findings must be verified in larger, randomised, prospective trials, including with extended patient follow-up.