Impaired Exercise Tolerance in Heart Failure: Role of Skeletal Muscle Morphology and Function

AbstractPurpose of ReviewTo discuss the impact of deleterious changes in skeletal muscle morphology and function on exercise intolerance in patients with heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF), as well as the utility of exercise training and the potential of novel treatment strategies to preserve or improve skeletal muscle morphology and function.Recent FindingsBoth HFrEF and HFpEF patients exhibit a reduction in percent of type I (oxidative) muscle fibers and oxidative enzymes coupled with abnormal mitochondrial respiration. These skeletal muscle abnormalities contribute to impaired oxidative metabolism with an earlier shift towards glycolytic metabolism during exercise that is strongly associated with exercise intolerance. In both HFrEF and HFpEF patients, peripheral “non-cardiac” factors are important determinants of the improvement in exercise tolerance following aerobic exercise training. Adjunctive strategies that include nutritional supplementation with amino acids and/or anabolic drugs to stimulate anabolic molecular pathways in skeletal muscle show gr eat promise for improving exercise tolerance and treating heart failure-associated sarcopenia, but these efforts remain early in their evolution, with no immediate clinical applications.SummaryThere is consistent evidence that heart failure is associated with multiple skeletal muscle abnormalities which impair oxygen uptake and utilization and ...
Source: Current Heart Failure Reports - Category: Cardiology Source Type: research