Strength Improvement of Knee Extensor Muscles in Patients with Chronic Heart Failure by Neuromuscular Electrical Stimulation

• Published in: Artificial organs Vol. 23; no. 5; pp. 432 - 435
• Main Authors: Quittan, Michael, Sochor, Andrea, Wiesinger, Günther F., Kollmitzer, Josef, Sturm, Barbara, Pacher, Richard, Mayr, Winfried
• Format: Journal Article
• Language: English
• Published: Boston, USA Blackwell Science Inc 01.05.1999
• Subjects: Chronic Disease; Chronic heart failure; Electric Stimulation Therapy - instrumentation; Electric Stimulation Therapy - methods; Evaluation Studies as Topic; Feasibility Studies; Female; Heart Failure - complications; Humans; Isometric Contraction - physiology; Knee Joint - physiology; Male; Middle Aged; Muscle Contraction - physiology; Muscle Fatigue - physiology; Muscle strength; Muscle Weakness - therapy; Neuromuscular electrical stimulation; Neuromuscular Junction - physiology; Range of Motion, Articular - physiology; Skeletal muscle; Strength improvement; Stroke Volume - physiology; Torque; Ventricular Dysfunction, Left - complications
• ISSN: 0160-564X; 1525-1594
• DOI: 10.1046/j.1525-1594.1999.06372.x

Patients with severe chronic heart failure (CHF) suffer from marked weakness of skeletal muscles. Neuromuscular electrical stimulation (NMES) proved to be an alternative to active strength training. The objective of this study was to test the feasibility and effectiveness of NMES in patients with chronic heart failure. Seven patients (56.0 ± 5.0 years, CHF for 20 ± 4 months, left ventricular ejection fraction 20.1 ± 10.0%) finished an 8 week course of NMES of the knee extensor muscles. The stimulator delivered biphasic, symmetric, constant voltage impulses of 0.7 ms pulse width with a frequency of 50 Hz, 2 s on and 6 s off. No adverse effects occurred. After the stimulation period, the isokinetic peak torque of the knee extensor muscles increased by 13% from 101.0 ± 8.7 Nm to 113.5 ± 7.2 Nm (p = 0.004). The maximal isometric strength increased by 20% from 294.3 ± 19.6 N to 354.14 ± 15.7 N (p = 0.04). This increased muscle strength could be maintained in a 20 min fatigue test indicating decreased muscle fatigue. These results demonstrate that NMES of skeletal muscles in patients with severe chronic heart failure is a promising method for strength training in this group of patients.