Exercise rehabilitation in cardiac resynchronization: systematic review and a meta-analysis

The benefit of exercise training in cardiac resynchronization therapy (CRT) recipients is not well established. We conducted a systematic review and meta-analysis to determine the effect of exercise training on clinical outcomes in CRT recipients.A comprehensive search until 2019 was conducted of MEDLINE, Epub, Embase, CINAHL and Cochrane databases as well as a bibliographic hand search to identify additional studies. We included all studies that compared aerobic exercise interventions in adults treated with CRT devices with adults treated with usual CRT care. These studies evaluated patient clinical characteristics, exercise testing measures, hemodynamic measures, echocardiography parameters, biomarkers and adverse events. Independent reviewers evaluated study eligibility, abstracted data and assessed risk of bias in duplicate. We used random-effect meta-analysis methods to estimate mean differences and odds ratios. Grades of Recommendation, Assessment, Development and Evaluation system were used to quantify absolute effects and quality of evidence. I² was used to evaluate heterogeneity.We identified seven studies, six randomized control trials and one observational study, totaling 332 CRT patients in the exercise intervention and 534 patients receiving usual care. Peak VO₂ was 2.4 ml/kg/min higher in the exercise group in comparison with the control group (pooled mean difference 2.26, 95% CI 1.38-3.13, I² = 53%, high quality). AT-VO₂ improved with exercise rehabilitation, and heterogeneity was considered low (pooled mean difference 3.96, 95% CI 2.68-5.24, I² = 0.0%, moderate quality).Peak VO₂ and AT-VO₂ are increased with aerobic exercise in CRT recipients, demonstrating a significant improvement in functional capacity.