Evaluation of perfusion conditions in cardiopulmonary bypass.

Fresh sections of left ventricular drill biopsies, taken at the beginning and end of cardiopulmonary bypass in 164 patients undergoing aortic valve replacement, have been analyzed for myocardial function. This has been assessed by changes in biochemical function, measured by semi-quantitative histochemical methods, and by changes in birefringence, measured quantitatively by polarization microscopy. It has been shown that continuous perfusion at 32 degrees C with the heart beating provided better preservation than did the other three perfusion procedures, in all of which the heart was fibrillating. More recently, in a small number of cases, cardioplegic arrest has been found to given even better preservation.