Ultrastructural, Enzyme Histochemical and Light Microscopic Investigation of the Myocardium in Cases Undergoing Open-Heart Surgery

Ultrastructural and enzyme histochemical changes in biopsies after perfusion in comparison with biopsies before perfusion demonstrated:(1) Negligible and probably reversible changes in cases with congenital heart disease as compared with those with acquired aortic valvular disease.(2) The myocardial protection of crushed ice during aortic occlusion for repeated periods of 20–25 minutes with intervals of 5 minutes of coronary perfusion proved to be very good.(3) Concomitant coronary artery disease in acquired aortic valvular disease with resulting impaired coronary perfusion increases the incidence of more advanced ultrastructural changes. The local hypothermia should be utilized.We are searching for criteria of the irreversibly damaged myocardium where a valve replacement will no longer improve the patient's condition. Therefore this investigation was performed to study the ultrastructure, enzyme histochemistry and light microscopy of the patients' myocardium. These findings are then correlated to the heart size and the myocardial reserve as measured by the left ventricular contraction, i.e. the difference between the left ventricular diastolic and systolic volume measured by angiocardiography.Another purpose of the invesigation was to study the ultrastructural changes in the myocardium during the different types of open-heart surgery. The different methods of myocardial protection can then be valuated and correlated to the patients' recovery and survival.