Ischaemic changes in human myocardial cells during cardioplegia: an ultrastructural morphometric study of patients with CIHD and aortic valve vitia.

Ultrastructural morphometric examinations of changes in myocardial cells of two groups of patients were carried out before and after cardioplegic ischaemia. The ACB group (aorto-coronary bypass) comprised patients suffering from chronic The ACB group (aorto-coronary bypass) comprised patients suffering from chronic ischaemic heart disease, whilst the AVR group (aortic valve replacement) consisted of patients suffering from combined aortic vitium. The morphometric stereological examinations of biopsy material revealed that the ultrastructural changes in heart muscle cells were different for the two groups. This fact suggests different adaptation mechanisms of the myocardial cells of the two groups. The changes observed involved i.a. mitochondria, which in the cardiomyocytes of the ACB group diminished in size and increased in quantity, whilst in the myocardial cells of the AVR group they increased in size and diminished in number. From this it can be inferred that in the ACB group biogenesis occurred, while in the AVR group a swelling or fusion of the mitochondria took place. The results obtained indicate that the hypertrophic myocardial cells of patients with chronic aortic valve disease have a worse state of preservation after cardioplegic ischaemia and after reperfusion than those of the patients suffering from chronic ischaemic heart disease, who seem to be better able to withstand cardioplegic ischaemia and hence also surgery.