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Strength Improvement of Knee Extensor Muscles in Patients with Chronic Heart Failure by Neuromuscular Electrical Stimulation
Author(s) -
Quittan Michael,
Sochor Andrea,
Wiesinger Günther F.,
Kollmitzer Josef,
Sturm Barbara,
Pacher Richard,
Mayr Winfried
Publication year - 1999
Publication title -
artificial organs
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.684
H-Index - 76
eISSN - 1525-1594
pISSN - 0160-564X
DOI - 10.1046/j.1525-1594.1999.06372.x
Subject(s) - isometric exercise , medicine , heart failure , stimulation , skeletal muscle , ejection fraction , weakness , cardiology , physical medicine and rehabilitation , muscle strength , muscle weakness , physical therapy , surgery
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.