Long-term neurostimulation of skeletal muscle: its potential for a tether-free biologic cardiac assist device.

Skeletal muscle has a tremendous capacity to adapt. This adaptive phenomenon is seen perhaps to the greatest extent when skeletal muscle is subjected to chronic low frequency stimulation via the motor nerve. There is a decrease in glycolytic enzymes and an increase in oxidative enzymes, as well as a change in the contractile proteins and an increase in the mitochondrial volume fraction of the muscle fiber. These adaptive changes result in a muscle that is considerably more fatigue-resistant. Specifically herein, we report on a pneumatic aortic counterpulsator device powered by skeletal muscle. These muscle pumps functioned continuously and pumped blood effectively in tether-free animals for several weeks.