Regional blood flow, muscle strength and skeletal muscle histology in severe congestive heart failure.

Regional blood flow to exercising skeletal muscle is reduced in patients who have undergone treatment for severe congestive heart failure, and is a key factor determining the limitation of exercise capacity. Recent studies have shown that the histology, contractile function and biochemistry of skeletal muscle are also abnormal. The mechanisms for both the reduced blood flow and the intrinsic abnormality of skeletal muscle are unknown. The interpretation of experimental data is complicated by different etiologies of heart failure, drug treatment, exercise protocols, the limitations of methods for the measurement of blood flow and metabolism in intact humans, and by the selection of particular groups of muscles for study that may not reflect changes in other muscles in the body.