Peripheral and respiratory muscles in chronic heart failure

Abstract

Since the shortness of breath correlates poorly with changes in lung function, changes in the respiratory muscles have been investigated. Studies have demonstrated diaphragmatic myopathy and atrophy similar, in part, to the changes in peripheral skeletal muscles. In CHF, type I (slow twitch) fibre atrophy is seen in respiratory as well as in peripheral muscles.The mechanism of these alterations remains to be elucidated. Studies into the mechanism of muscle dysfunction in congestive heart failure are relevant to the prospect of treatment of the changes in peripheral and respiratory muscles.

Respiratory muscle function and exercise intolerance in heart failure

“…In contrast to what is found in limb muscles, respiratory muscle biopsies have shown increased oxidative and lipolytic enzymatic activity and reduced glycolytic activity in these patients [38][39][40]. In addition, there is a shift from fast to slow myosin heavy-chain isoforms, probably induced by myogenic regulatory factors as a likely adaptation to the increased effort of breathing [40,41].…”

An alternative approach to understanding the pathophysiological mechanisms of chronic heart failure

“…If heart failure worsens, and inflammation becomes more dominant, cachexia is seen and then changes associated with this can be observed in the muscles. This approach can explain the differences seen in peripheral skeletal muscle (reduced work) and the diaphragm (increased work) in patients with heart failure and the occurrence of specific muscle changes associated with the disease process when heart failure is more advanced [78][79][80][81].…”

Early Occurrence of Respiratory Muscle Deoxygenation Assessed by Near-Infrared Spectroscopy During Leg Exercise in Patients With Chronic Heart Failure

“…Recent studies reported that chronic inadequate blood flow in the diaphragmatic muscle (the main respiratory muscle) in CHF patients results in muscular degeneration and increased fragility of the diaphragm, which is the cause of diaphragmatic muscle fatigue at a low minute ventilation volume, and early recruitment of the accessory respiratory muscles. [17][18][19][20] Therefore, respiratory muscle fatigue in CHF patients is not only associated with high frequency fatigue but also with low frequency fatigue caused by muscular tissue damage.…”