Abstract 21391: Combined Aerobic and Inspiratory Muscle Training Versus Aerobic Training Alone in Heart Failure: A Meta-Analysis of Randomized Controlled Trials

Abstract

Background: Abnormal ventilatory response contributes to exercise intolerance in patients with chronic heart failure (CHF). Previous meta-analysis showed that inspiratory muscle training (IMT) is beneficial for improving respiratory muscle strength and functional capacity in patients with CHF. However, whether the combination of IMT and aerobic training (AT) could further improve ventilatory response during exercise in patients with CHF is not clear. Purpose: The aim of this meta-analysis was to investigate the effect of IMT in combination with AT on ventilatory response during exercise in patients with CHF. Methods: We searched the following electronic databases (from inception to January 2017): PubMed, Embase, MEDLINE, and Cochrane Central Register of Controlled Trials (from January 2000 to January 2017) for relevant literature. We included randomized controlled trials (RCT) that compared IMT+AT with AT in which the outcomes was to assess ventilatory response (peak oxygen uptake and minute ventilation/carbon dioxide production (VE/VCO2) slope), and maximal inspiratory pressure (PImax)) during exercise in patients with CHF. A random-effects model was used for the main analysis. Results: Of 63 identified studies, three RCTs with a total of 94 CHF patients met the inclusion criteria. Compared to AT alone, combined IMT and AT significantly increased PImax (mean difference 18.7 cmH2O, 95% CI: 10.2 to 27.2; p<0.0001) but had no effect on peak oxygen uptake (mean difference 0.7; 95% CI: -1.3 to 2.7; p=0.49) or VE/VCO2 slope (mean difference -2.8; 95%CI: -8.1 to 2.6; p=0.31). Subgroup analyses showed intensive inspiratory training makes further improvement in PImax and Minnesota Living with Heart Failure Questionnaire (mean difference -4.22; 95% CI -7.69 to -0.75; p=0.02), irrespective of baseline inspiratory muscle strength and ejection fraction. Conclusions: The results showed that in patients with CHF, IMT in combination with AT training could improve respiratory muscle strength but had no impact on ventilatory response during exercise. These findings suggested that the inspiratory muscle insufficiency might not be the main cause for abnormal ventilatory response during exercise in patients with CHF.