Skeletal muscle as a myocardial substitute

Skeletal muscle has long been used in the field of cardiac surgery. Its use has progressed from providing myocardial reinforcement to assisting the he art by actively pumping blood. Early experiments revealed that skeletal mus cle assistance could augment pressures and blood flow; however, the results were short-lived due to muscle fatigue. It was later shown that skeletal m uscle can be conditioned electrically to be fatigue resistant and therefore may be useful for performing cardiac-type work Once the details were forme d of how to stimulate and manipulate the muscle to assist the heart, severa l configurations were devised. Cardiomyoplasty and aortomyoplasty refer to wrapping skeletal muscle around the heart or aorta, respectively. These tec hniques have been applied in humans; however, the effectiveness is controve rsial. Although most patients improve clinically, the hemodynamic parameter s have not shown consistent improvements, and survival data are unknown. sk eletal muscle ventricles offer a promising alternative to both cardiomyopla sty and aortomyoplasty. These are completely separate pumping chambers cons tructed from skeletal muscle and connected to the circulation in a variety of configurations. Although these have not been tried in humans, the animal data appear quite convincing. The skeletal muscle ventricles have shown th e greatest improvements on hemodynamic parameters with great stability over time.