Inspiratory Muscle Training and Functional Electrical Stimulation for Treatment of Heart Failure With Preserved Ejection Fraction: The TRAINING-HF Trial

Despite the prevalence of heart failure with preserved ejection fraction (HFpEF), there is currently no evidence-based effective therapy for this disease. This study sought to evaluate whether inspiratory muscle training (IMT), functional electrical stimulation (FES), or a combination of both (IMT + FES) improves 12- and 24-week exercise capacity as well as left ventricular diastolic function, biomarker profile, and quality of life in HFpEF.

A total of 61 stable symptomatic patients (New York Heart Association II-III) with HFpEF were randomized (1:1:1:1) to receive a 12-week program of IMT, FES, or IMT + FES vs usual care. The primary endpoint of the study was to evaluate change in peak exercise oxygen uptake at 12 and 24 weeks. Secondary endpoints were changes in quality of life, echocardiogram parameters, and prognostic biomarkers. We used a mixed-effects model for repeated-measures to compare endpoints changes.

Mean age and peak exercise oxygen uptake were 74 ± 9 years and 9.9 ± 2.5mL/min/kg, respectively. The proportion of women was 58%. At 12 weeks, the mean increase in peak exercise oxygen uptake (mL/kg/min) compared with usual care was 2.98, 2.93, and 2.47 for IMT, FES, and IMT + FES, respectively (P < .001) and this beneficial effect persisted after 6 months (1.95, 2.08, and 1.56; P < .001). Significant increases in quality of life scores were found at 12 weeks (P < .001). No other changes were found.

In HFpEF patients with low aerobic capacity, IMT and FES were associated with a significant improvement in exercise capacity and quality of life. This trial was registered at ClinicalTrials.gov (Identifier: NCT02638961)..