EFFICACY OF A SKELETAL MUSCLE-POWERED DYNAMIC PATCH .2. RIGHT-VENTRICULAR ASSISTANCE

The purpose of this study was to assess the feasibility of using a ske letal muscle-powered dynamic patch to assist the failing right ventric le. Seven adult mongrel dogs were used in the study. The proximal port ion of the left latissimus dorsi muscle was harvested and reattached t o the actuator to serve as a skeletal muscle energy convertor. The rig ht ventricular free wall was fully excised and the dynamic patch was i mplanted under cardiopulmonary bypass. After weaning from cardiopulmon ary bypass, the latissimus dorsi muscle was stimulated using a burst f requency of 33 Hz, a burst duration of 200 ms, and 1:2 synchronous mod e stimulation with the native R wave. Latissimus dorsi muscle stimulat ion increased systolic aortic pressure (78 versus 91 mm Hg; p < 0.01), mean aortic pressure (56 versus 62 mm Hg; p < 0.05), aortic blood flo w (0.73 versus 0.97 mL; p < 0.01), and systolic right ventricular pres sure (41 versus 56 mm Hg; p < 0.01). The mean right atrial pressure de creased from 14 to 9.6 mm Hg (p < 0.01). Our results demonstrate that the use of a right ventricular dynamic patch powered by a skeletal mus cle linear-type actuator can not only function as a right ventricular free wall substitute but also lead to the augmentation of right ventri cular and global cardiac function.