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 (F_max; N) and isokinetic peak torque (PT_max; 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 F_max (from 224.5±96.8 N to 340.0±99.4 N; p<0.001), and also PT_max (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. (Circ J 2006; 70: 75 - 82)