Image and DNA analysis of hypertrophic myocytes in hypertensive heart disease and hypertrophic cardiomyopathy

OBJECTIVE: To investigate differences in the pathophysiology of cardiac hypertrophy between patients with hypertensive heart disease (HHD) and hypertrophic cardiomyopathy (HCM). STUDY DESIGN: The study group consisted of 30 autopsied heart disease patients (10 HHD, 10 HCM and 10 noncardiac heart disease). DNA synthesis by hypertrophic cardiac myocytes was examined, and three-dimensional myocyte structure image was investigated. DNA synthesis and the cell cycle were investigated by flow cytometry using autopsy material. Three-dimensional myocyte structure image was visualized. RESULTS: The percentage of cells in G2M phase of the cell cycle was significantly decreased in the myocardium of autopsied hearts with HCM as compared with hearts with HHD (HCM:HHD = 1.2 +/- 1.1%: 7.7 +/- 2.6%, mean +/- SD). Hypertrophic myocytes of HCM characteristically possessed myocardial disarray and irregular side-to-side branch connections between myocytes. No myocyte disarray or irregular connections could be observed in HHD. CONCLUSION: These results suggest that the mechanism of cardiac hypertrophy differs between patients with HHD and HCM and also suggest dissimilar cell vitality and latent proliferative viability of hypertrophic myocytes in a hypertrophic process between HHD and HCM. That is, hypertrophic myocytes may be called "restricted" myocytes in a morphologic and biochemical sense.