Efficacy of inspiratory muscle training in chronic heart failure patients: A systematic review and meta-analysis

Abstract

Introduction: Inspiratory muscle training (IMT) offers an alternative to exercise training (ExT) in the most severely deconditioned heart failure patients who are unable to exercise. We conducted a meta-analysis to determine magnitude of change in peak VO₂, six minute walk distance (6MWD), Quality of Life measured by the Minnesota Living with Heart Failure Questionnaire (MLWHFQ), maximal inspiratory pressure (PI max) and ventilatory equivalent for carbon dioxide (VE/VCO₂ slope) with IMT. Methods: A systematic search was conducted of randomized, controlled trials of IMT therapy in CHF patients using Medline (Ovid) (1950-February 2012), Embase.com (1974-February 2012), Cochrane Central Register of Controlled Trials and CINAHL (1981-February 2012). The search strategy included a mix of MeSH and free text terms for the key concepts heart failure, inspiratory or respiratory muscle training, exercise training. Results: The eleven included studies contained data on 287 participants: 148 IMT participants and 139 sham or sedentary control. Compared to control groups, CHF patients undergoing IMT showed a significant improvement in peak VO₂ (+ 1.83 ml kg⁻¹ min⁻¹, 95% C.I. 1.33 to 2.32 ml kg⁻¹ min⁻¹, p < 0.00001); 6MWD (+ 34.35 m, 95% C.I. 22.45 to 46.24 m, p < 0.00001); MLWHFQ (- 12.25, 95% C.I. - 17.08 to - 7.43, p < 0.00001); PImax (+ 20.01, 95% C.I. 13.96 to 26.06, p < 0.00001); and VE/VCO₂ slope (- 2.28, 95% C.I. - 3.25 to - 1.30, p < 0.00001). Conclusions: IMT improves cardio-respiratory fitness and quality of life to a similar magnitude to conventional exercise training and may provide an initial alternative to the more severely de-conditioned CHF patients who may then transition to conventional ExT.