Activity-rest stimulation of Latissimus Dorsi for Cardiomyoplasty: 1-year results in sheep

Background. In dynamic cardiomyoplasty electrostimulation achieves full transformation of the latissimus dorsi (LD); therefore, its slowness limits the systolic support. Daily activity-rest Could maintain partial transformation of the LD. Methods. Sheep LD were burst-stimulated either 10 or 24 hours/day. Before and 2, 4, 6, and 12 months after stimulation, LD power output, fatigue resistance, and tetanic fusion frequency were assessed. Latissimus dorsi were biopsied at 6 months, and sheep sacrificed at 12 months. Results. After 1 year of 10 hours/day stimulation LD was substantially conserved and contained large amounts of fast type myosin. From 2 months to 1 year of stimulation the power per muscle of the daily rested LD was greater than that of the left ventricle, being three to four times higher than in the 24-hour/day stimulation. Conclusions. If extended to humans, these results could be the rationale for the need of a cardiomyostimulator, whose discontinuous activity could offer ...