Power output of skeletal muscle ventricles in circulation: Short-term studies

Abstract

Skeletal muscle ventricles (SMVs) were constructed from preconditioned latissimus dorsi muscles in eight dogs and then connected to each animal's systemic arterial circulation in short-term experiments. The lengths of time that SMVs could produce hemodynamic work as left ventricular assist devices were recorded. After 4 hr of continuous pumping at approximately 55 beats/min, six of eight SMVs were able to generate systolic pressures of 128 ± 23 mm Hg and flows of 340 ± 31 ml/min, representing 20 ± 4% of the animals' cardiac output. After 8 hr of continuous pumping, five of the eight SMVs generated pressures of 110 ± 15 mm Hg and flows of 308 ± 88 ml/min, or 15 ± 7% of the animals' cardiac output. The stroke work produced by the SMVs was intermediate between that of the animals' left and right ventricles. Although the SMVs were stimulated to contract at only about one-third the heart rate, the power output of the SMVs approximated that of the right ventricles because of the greater stroke work of the SMVs. Two SMVs functioned as LVADs for 14 hr. Deterioration in SMV function eventually occurred. In each case, however, complications such as anemia, hypoxia, and hypotension, which are inherent to prolonged short-term experiments of this type, contributed to the deterioration of SMV function. The results presented here suggest that skeletal muscle has the potential to directly support the circulation; however, the length of time such muscle pumps are capable of functioning has yet to be determined.