SKELETAL-MUSCLE STRENGTH AND ENDURANCE IN CHRONIC CONGESTIVE-HEART-FAILURE SECONDARY TO IDIOPATHIC DILATED CARDIOMYOPATHY

Long-term heart failure may affect both skeletal muscle strength and endurance as a result of fiber atrophy, decreased percentage of oxidative muscle fibers, lowered oxidative enzyme capacity and a reduced number of capillaries per fiber found in patients with chronic congestive heart failure (CHF).1-4 Isometric strength of the musculus quadriceps femoris in patients with CHF has been shown to be markedly lower,5,6 but also unaltered,7 in comparison with healthy subjects. In addition, patients with CHF have a lower muscular endurance in the forearm, as well as postural muscles, than in healthy subjects.5,7,8 Although Minotti et al7 showed a greater force reduction after an anaerobic, short-lasting bout of knee extensions in patients with CHF, it remains to be shown that patients respond in the same way after a challenge that activates the metabolism to a higher degree. The aim of the present study was to investigate whether muscular strength and endurance are lower in patients with CHF, and if so, to determine the degree and manner in which functional capacity is altered. Specifically, this study examined the force velocity relation of musculus quadriceps femoris during single isometric, concentric and eccentric, as well as repeated, muscular contractions. Furthermore, the muscle cross-sectional area was measured to study specific tension and possible atrophy of the muscles of patients with CHF in relation to healthy subjects. © 1994.