The impact of exercise training for chronic heart failure patients with cardiac resynchronization therapy: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE: Systematically review the current published literature on the impact of exercise training (ET) in chronic heart failure (CHF) patients who were conducted cardiac resynchronization therapy (CRT). METHODS: PubMed, EMBASE, and the Cochrane Library of Controlled Trails databases were searched for trials comparing the additional effects of ET in CHF patients after CRT implantation with no exercise or usual care control up until 2020.03.07. We independently screened the literature, extracted data, employed the tool for the assEssment of Study qualiTy and reporting in EXercise (TESTEX) to evaluate study quality and risk of bias, and performed meta-analysis with Revman 5.3 software. RESULTS: Eight trials were identified for qualitative analysis and 7 randomized controlled trails (RCTs) included 235 participants (120 ET; 115 controls) for quantitative analysis. The results showed that the maximal workload (mean difference [MD] 26.32 W, 95% CI 19.41–33.23; P < .00001, I(2) = 0%) and the exercise duration (MD 68.95 seconds, 95% CI 15.41–122.48; P = .01, I(2) = 76%) had significant improvement in the ET group versus control. Subgroup analysis showed that compared with control, the change in peak oxygen uptake (VO(2)) (MD 3.05 ml/kg/minute, 95% CI 2.53–3.56; P < .00001, I(2) = 0%), left ventricular ejection fraction (LVEF) (MD 4.97%, 95% CI 1.44–8.49; P = .006, I(2) = 59%), and health related quality of life (HRQoL) (the change in Minnesota living with heart failure questionnaire [MLHFQ]: MD −19.96, 95% CI −21.57 to −18.34; P < .00001, I(2) = 0%) were significantly improved in the light to moderate intensity training (non-HIT) group, while there seemed no statistical difference of above endpoints in the high intensity training (HIT) group. CONCLUSION: During the short term (up to 6 months), non-HIT could improve exercise capacity, cardiac function, and HRQoL in CHF patients with CRT. However, due to the small number of participants, a high-quality large-sample multicenter trial is demanded.