Background: Randomised controlled trials generally suggest that cardiac resynchronisation improves outcomes in patients with heart failure due to left ventricular systolic dysfunction and cardiac dyssynchrony. Our objective was to provide a valid synthesis of the effects of CRT on mortality, major morbidity, quality of life and implantation success rates.
Methods: Systematic overview and meta-analysis of randomised trials, both blinded and open, comparing cardiac resynchronisation with control. The primary outcome was all-cause mortality, and secondary outcomes included hospitalisation for worsening heart failure, quality of life and implantation success rates.
Results: We identified 8 randomised trials which included 3380 patients and observed a total of 524 deaths. Follow-up ranged from 1 month to a mean of 29.4 months. Most trials were of high quality, with centrally administered randomisation and few patients lost to follow-up. CRT reduced mortality in these trials (odds ratio 0.72, 95% CI 0.59 to 0.88). In addition CRT reduced hospitalisation for worsening heart failure (odds ratio 0.55, 95% CI 0.44 to 0.68) and improved quality of life as measured by the Minnesota Living with Heart Failure Questionnaire (weighted mean difference -7.1, 95% CI -2.9 to -11.4). Implantation success rates in the trials were 87% or greater.
Conclusion: Cardiac resynchronisation in patients with heart failure characterised by dyssynchrony substantially reduces all-cause mortality, major morbidity and improves quality of life.