Low-frequency electrical stimulation increases muscle strength and improves blood supply in patients with chronic heart failure

Abstract

Background: This study was designed to evaluate the effects of low-frequency electrical stimulation (LFES) on muscle strength and blood flow in patients with advanced chronic heart failure (CHF). Methods and Results: Patients with CHF (n=15; age 56.5±5.2 years; New York Heart Association III-IV; ejection fraction 18.7±3.3%) were examined before and after 6 weeks of LFES (10 Hz) of the quadriceps and calf muscles of both legs (1 h/day, 7 days/week). Dynamometry was performed weekly to determine maximal muscle strength (Fmax; N) and isokinetic peak torque (PTmax; Nm); blood flow velocity (BFV) was measured at baseline and after 6 weeks of LFES using pulsed-wave Doppler velocimetry of the right femoral artery. Six weeks of LFES significantly increased Fmax (from 224.5±96.8 N to 340.0±99.4 N; p<0.001), and also PTmax (from 94.5± 41.5 Nm to 135.3±28.8 Nm; p<0.01). BFV in the femoral artery increased after 6 weeks from 35.7±15.4 cm/s to 48.2±18.1 cm/s (p<0.05); BFV values at rest before and after 6 weeks of LFES did not differ significantly. Conclusions: LFES may improve muscle strength and blood supply, and could be recommended for the treatment of patients with severe CHF.