Safety and efficacy of home-based neuromuscular electrical stimulation on physical function in frail older patients with heart failure: a randomized crossover study

Introduction Neuromuscular electrical muscle stimulation (NMES) therapy is a non-volitional method used to elicit muscle contractions without inducing dyspnea. By stimulating skeletal muscles, NMES therapy enhances exercise capacity, increases muscle mass, and improves muscle function in patients with heart failure (HF). Recently, supervised NMES has been reported to safely increase lower limb motor function in frail older patients hospitalized for acute HF. However, the safety and effectiveness of home-based NMES therapy remain uncertain, particularly in frail older patients with HF. Purpose This study aimed to examine the safety and efficacy of home-based NMES therapy on lower extremity function in frail older patients with HF. Methods Eight frail older patients (age ≥ 75 years) with HF undergoing home or ambulatory cardiac rehabilitation (CR) were enrolled in this randomized, open-label, crossover study. Participants underwent CR plus home-based NMES therapy and CR alone for 8 weeks each in random order, separated by a 4-week washout period. NMES with a 50-Hz frequency was administered for 50 minutes per day, five times per week with electrodes placed on the quadriceps, gastrocnemius, and soleus muscles. Patients participated in a supervised exercise program, a combination of endurance and resistance training with light to moderate intensity, once or twice times weekly at the hospital or at home. Adverse cardiac events and plasma brain natriuretic peptide (BNP) and creatine kinase (CK) levels were assessed as indicators of NMES safety. The Short Physical Performance Battery (SPPB) and the Barthel Index (BI) were measured as parameters of lower extremity function and activities of daily living. Results The average age of the patients was 85 years, and three were men. All patients completed the study without experiencing any adverse cardiac events. In comparison with CR alone, there were no significant effects of CR plus home-based NMES therapy on BNP (P = 0.51), CK (P = 0.34), or BI (P = 0.17). The 8-week treatment with CR plus home-based NMES therapy resulted in a significant increase in SPPB score compared to CR alone (P < 0.05). Conclusions Home-based NMES therapy was safe and improved lower extremity function in frail older patients with HF undergoing CR.