Abstract
The present study addressed the optimal application of the MCAD. Using the canine unconditioned and minimally dissected latissimus dorsi muscle, MCAD (full stroke: 60ml) was assembled with driving dome for counterpulsation (CP) or driving chamber for ventricular bypass (VB) and set up in the mock circuit. At systemic afterload, MCAD functioned as CP with 60mmHg preload, resulted in maximum stroke work of 4.4×106 erg, however did not as left side VB. On the other hand, at pulmonary afterload, the greater stroke work of 1.3×106 erg than that of canine right ventricle was obtained using bellows chamber. The key issues for augmentation of MCAD performance are a sufficient muscle stretch during pump diastole, good filling sensitivity and efficient power transmission from muscle to the pump diaphragm. In conclusion, CP and right ventricular support are optimal for MCAD application, while left ventricular support is marginal. To circumvent the disadvantage, active filling assist mechanism and booster ejection pump will be necessary.
