Abstract
Many investigators have studied the effectiveness of various types of assisted circulation to relieve the failing heart. Counterpulsation (C-P) and Selective Left Ventricular Bypass (SLVB) are powerful procedures for mechanically supporting the left-sided heart. The former is efficacious for reducing the left ventricular pressure work, the latter for it's volume work mainly. Theoretically, synchronization of the pump action with the cardiac cycle is desirable for assisting the failing left ventricle. A combined method of SLVB and C-P will probably reduce the left ventricular work markedly, and there-fore, it will be the most reasonable assisted circulation for left-sided heart failure. This method is named Selective Left Ventricular Partial Bypass with Counterpulsation (Sy. PB) by the author. The Standard Isochronous Myocardial Augmentation System (SIMAS○!R) was used as a specially designed pump equipped with a synchronizing device with ECG required for this purpose, and with SIMAS it was easy to obtain proper synchronization of the pump action with ECG. SIGMAMOTOR Model TM-2 was used as a pumping device in the cases of asynchronous bypass. After a thoracotomy and laparotomy done, an arterial cannula made of rigid polyethylene for counterpulsation was inserted through the abdominal aorta into the thoracic aorta. In group I (of 4 healthy mongrel dogs), the bypass techniques performed were SLVB without a left ventricular vent (TB-Vc), SLVB with a left ventricular vent (TB-Vo) and Asynchronous Selective Left Ventricular Partial Bypass (Asy. PB) ; in group II (of 5 healthy mongrel dogs), TB-Vc, Asy. PB and Sy. PB were performed.
