Ultrastructural correlates of reduced cardiac function in human heart disease.

The ultrastructural correlates of a decrease in cardiac function resulting in heart failure are unknown. For this reason, transmural needle biopsies were taken during cardiac surgery from patients with aortic valve disease (AD, n = 143) and coronary heart disease (CHD, n = 136) and examined by electron microscopy. Ultrastructural features were: occurrence of abnormal but still viable nuclei and mitochondria combined with lack of myofibrils in greatly enlarged myocardial cells plus an increased amount of fibrosis in patients with AD. In CHD most myocardial cells were of normal size or atrophic, reduced in number and showed signs of subcellular degeneration. Fibrosis was greatly increased. These findings were confirmed in both groups of patients by quantitative analysis (morphometry). Cardiac failure was diagnosed and clinically treated in about 25% of all patients investigated in this study. The loss of specific myocardial cellular components or loss of entire cells are the morphological correlates of cardiac failure in different types of heart disease.