Improved performance after neuromuscular electrical stimulation in hospitalized patients with severe heart failure

Aims Patients with severe heart failure often suffer from sarcopenia, which contributes to reduced exercise capacity and might worsen during a hospital stay. The study thus aimed to investigate the safety of neuromuscular electrical stimulation (NMES) and its effects on functional performance in hospitalized patients with severe heart failure, including patients with electronic cardiac devices, in addition to regular physiotherapeutic treatment. Methods Based on their functional performance level, 30 patients (48.0 ± 14.3 years; 19 males, 11 females) were stratified and 1:1 randomized to either the control group (CON) with regular physiotherapeutic treatment only, or the stimulation group (STIM), who additionally received a 2-week NMES of the leg muscles. Functional performance was evaluated using a battery of 5 distinct functional tests (including the 6-minute walking test (6MWT) and the sit-to-stand test (SST)) administered at baseline (T0) and after 2 weeks (T1). The individual test outcomes were subsequently aggregated into a composite measure, the StimFIT5-Score. Furthermore, the PHQ9-Score was assessed to evaluate depressive symptoms. Results No adverse side effects occurred and specifically, no electromagnetic interferences in patients with cardiac electronic devices were detected. For the StimFIT5-Score, a significantly greater improvement (p=0.002) was observed in STIM (+8.2 points, p<0.001) compared to CON (+3.6 points, p=0.006). The percentage improvement in the StimFIT5-Score was the greatest in STIM-patients with low StimFIT5-Scores at baseline (+53%). STIM showed significant improvements from T0 to T1 in the 6MWT (+ 68m, p<0.001) and SST (+3.8 repetitions, p<0.001) but with no significantly greater improvement in both tests (6MWT p=0.087, SST p=0.085) compared to CON (6MWT +35m, p=0.05; SST +1.7 repetitions, p=0.078). There was also no significant difference (p=0.078) in the improvement of the PHQ9-Score in STIM (-3.2 points, p<0.001) compared to CON (-2.4 points, p=0.013). In STIM, no sex-specific differences were observed for the improvement in StimFIT5-Score (p=0.388), 6MWT (p=0.685), and SST (p=0.720), with both female and male patients showing significant improvements from T0 to T1. Conclusions In this study, NMES was safely applied in patients with severe heart failure and electronic cardiac devices. 2 weeks of NMES in addition to regular physiotherapeutic treatment had significant effects on functional performance measured by StimFIT5-Score, independent of sex and with the greatest benefits observed in the least fit patients (schematic overview see Figure 1).