Comparison of low-frequency electrical myostimulation and conventional aerobic exercise training in patients with chronic heart failure

Abstract

Background

Physical training is recommended as an efficient therapy in patients with chronic heart failure (CHF). Low-frequency electrical myostimulation (EMS) has recently been suggested as a good alternative to conventional aerobic training. The aim of this study was to compare the effects of EMS and conventional exercise training in patients with moderate to severe CHF.

Methods

Twenty-four patients with stable CHF (56.7±7.3 years, New York Heart Association grades II and III) underwent 5 weeks of exercise training, 5h a week, using EMS (n=12) or conventional (n=12) training programmes. At baseline and after the training period, patients performed a symptom-limited cardiopulmonary test, a 6-min and a 200-m walk exercises and an evaluation of maximal knee extensor strength.

Results

Oxygen uptake (VO₂) and workload at the end of exercise (peak values) and at ventilatory threshold increased after EMS (P ≤ 0.05) and conventional exercise (P<0.05) training programmes. The slope of the relationship between VO₂ and workload was reduced after EMS (P<0.05). The time to recover half of peak VO₂ decreased irrespective of the training programme (P<0.001). EMS and conventional exercise training programmes also increased the maximal knee extensor strength (P<0.05), the distance walked in 6 min (P<0.01) and decreased the time elapsed to cover 200 m (P<0.05). These improvements were not statistically different between EMS and conventional exercise.

Conclusion

In patients with moderate to severe CHF, 5 weeks of EMS and conventional exercise training produce similar improvements to exercise capacity and muscle performance.