Exercise intolerance in chronic heart failure--skeletal muscle dysfunction and potential therapies.

Chronic heart failure (CHF) is characterized as a clinical disorder displaying exercise intolerance; patients typically complain of early muscular fatigue. Previously, it was thought to be simply a failure of perfusion to the exercising musculature and consequent early onset of intramuscular acidosis in CHF. However, improved hemodynamics by cardiotonic agents did not lead to an increase in exercise tolerance. Later studies have shown that intrinsic skeletal muscle abnormalities exist in patients with CHF and could induce the early anaerobic metabolism that limits exercise tolerance. We review the clinical importance of skeletal muscle abnormalities in patients with CHF. Considering the significance of peripheral muscle abnormalities and their development might help physicians and researchers better understand the mechanisms of well-established exercise training and pharmacological therapies that have been shown to improve the prognosis for CHF, and thus develop potential novel therapies.