Effects of left heart bypass on cardiac performance following myocardial ischemia.

A series of nine dogs underwent 20 minutes of myocardial ischemia by cross clamping the aorta while total cardiopulmonary bypass. The four dogs that did not have subsequent left bypass all showed a deterioration of ventricular function curve 30 minutes after restarting the heart beat when compared to their own preischemic values. The five animals which were supported for 30 minutes in left heart after bypass all showed essentially unchanged cardiac function after bypass. This study suggests that an improvement of myocardial performance after ischemic damage can be achieved with left heart bypass.