Skeletal muscle alterations in patients with chronic heart failure.

AIMS To investigate skeletal muscle in patients with chronic heart failure and controls, and relate skeletal muscle variables to functional class, exercise capacity, central haemodynamics, muscle strength and medical treatment. METHODS Biopsy from the lateral vastus muscle was obtained in 43 patients and 20 controls. Right sided heart catheterization was performed in 19 patients and maximal exercise testing in 26 patients. In nine patients muscle strength was measured. Patients had higher lactate levels, higher lactate dehydrogenase activity, and lower oxidative enzymes activity than controls. In patients, the percentage of type I fibres and capillarization were decreased while the percentage of type II B fibres were increased. Lactate dehydrogenase activity correlated with exercise capacity, muscle strength and right atrial pressure. Digoxin-treated patients had significantly lower oxidative enzyme activity than patients without digoxin treatment. CONCLUSION Patients with chronic heart failure have several skeletal muscle abnormalities. Central haemodynamics and medical treatment may, in addition to inactivity, be important in skeletal muscle changes.