Electrical myostimulation improves left ventricular function and peak oxygen consumption in patients with chronic heart failure: results from the exEMS study comparing different stimulation strategies

Abstract

Aims: Electromyostimulation (EMS) of thigh and gluteal muscles is a strategy to increase exercise capacity in patients with chronic heart failure (CHF). The aim of this non-randomised pilot study was to investigate the effects of different stimulation strategies in CHF patients using a newly developed stimulation suit also involving trunk and arm muscles [extended electromyostimulation (exEMS)] in comparison with EMS therapy limited to gluteal and leg muscles (limEMS).

Methods: 60 individuals joined the EMS training programme. Stable CHF patients (NYHA class II-III) received either exEMS (22 patients, 15 males, mean age 59.95 ± 13.16 years) or limEMS (12 patients, 9 males, 62.75 ± 8.77 years). 26 participants served as healthy control group (CG) receiving exEMS. Training was performed for 10 weeks twice weekly for 20 min, and the level of daily activity remained unchanged. Effects on exercise capacity, oxygen uptake, left ventricular function (EF) and biomarkers were evaluated.

Results: There was a significant increase of oxygen uptake at aerobic threshold in all groups (exEMS: 13.7 ± 3.9-17.6 ± 5.1 ml/kg/min (+28.46%, p < 0.001); limEMS 13.6 ± 3.0-16.0 ± 3.8 ml/kg/min (+17.6 %, p = 0.003); CG 15.0 ± 4.9-17.0 ± 6.4 ml/kg/min (+13.3%, p = 0.005). LVEF increased from 38.3 ± 8.4 to 43.4 ± 8.8% (+13.3%, p = 0.001) (limEMS 37.1 ± 3.0-39.5 ± 5.3% (+6.5%, p = 0.27); CG 53.9 ± 6.7-53.7 ± 3.9% (-0.4%, p = 0.18). In CHF patients changes in oxygen consumption and LVEF were higher in the exEMS group than in limEMS (not significant). Maximal workload improved in healthy controls (p = 0.002) but not in CHF patients.

Conclusion: Extended EMS can improve oxygen uptake and EF in CHF. In patients with limited EMS and in control patients without heart failure but extended EMS, oxygen uptake can be improved but EF is unaltered. For all groups, NT proBNP is unaffected by EMS.