Effect of Variable and Constant-Frequency Train in Latissimus Dorsi Muscle Stimulation

We tested the hypothesis that increased hemodynamic augmentation and mechanical performance could be achieved by using a variable frequency pulse train (VFT) to stimulate the latissimus dorsi muscle (LDM), compared to the conventional constant frequency pulse train (CFT) used in cardiomyoplasty. In dogs (n = 6), a vascular delayed LDM was wrapped posteriorly around the heart. LDM was conditioned for 9 weeks using implantable cardiomyostimulator. The hemodynamic parameters were recorded using VFT and CFT LDM stimulation with 7, 6 and 5-pulses, and compared to non-stimulated beats (NS). Both CFT and VFT LDM stimulation significantly increased pressures, flow, and stroke work. However, compared to CFT, VFT stimulation resulted in significant stroke power (20.6%), maximum peak aortic flow (20.1%) and maximum LV dP/dt (14.6%). These results suggested that stimulation of the LDM using VFTs is potentially greater beneficiary for application in cardiomyoplasty.