Assisted Circulation

Assistance to the failing heart by extracorporeal circulation techniques may benefit a number of disease states involving the right or left ventricle or both. A partial list of such conditions would include: 1. Acute myocardial infarction 2. Shock due to hemorrhage or sepsis 3. Postoperative states (postcardiotomy) 4. Preoperative states (treatment of intractable failure prior to surgical correction of cardiac disease) 5. Pulmonary disease with right ventricular failure The goal of mechanical assistance to the heart is a decrease in the external work to be furnished by the failing myocardium and maintenance of adequate pulmonary and systemic flows and pressures. The following methods of mechanical assistance have been used clinically and/or experimentally. 1. Cardiopulmonary bypass, partial or total * 2. Veno-arterial pumping without oxygenator (partial bypass)⁵,⁹,¹²,³⁰ 3. Right heart bypass 4. Left heart bypass³,⁴,⁸,²¹ 5. Counterpulsation (postsystolic augmentation) † A limitation inherent in all of these methods is the