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

OBJECTIVE: To investigate differences in the pathophysiology of cardiac hyp ertrophy between patients with hypertensive heart disease (HHD) and hypertr ophic cardiomyopathy (HCM). STUDY DESIGN: The study group consisted of 30 autopsied heart disease patie nts (10 HHD, 10 HCM and 10 noncardiac heart disease). DNA synthesis by hype rtrophic cardiac myocytes was examined, and three-dimensional myocyte struc ture image was investigated. DNA synthesis and the cell cycle were investig ated by flow cytometry using autopsy material. Three-dimensional myocyte st ructure image tuns visualized. RESULTS: The percentage of cells in G2M phase of the cell cycle was signifi cantly 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). Hyp ertrophic 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 my be called "restricted" myocytes in a morphologic and biochemical sense.