Objective: The aim of the study was to detect changes in left ventricular cardiomyocyte size and shape in response to chronic ischemia and loss of cardiac tissue (myocardial infarction) during the course of ischemic heart disease (IHD).
Material and methods: Left ventricular cardiomyocyte dimensions (diameter and length) were estimated histomorphometrically, and their cross-sectional area and volume were assessed in 85 males who died suddenly out of hospital (within 6 hours of the onset of the terminal event) due to the acute first (preinfarction IHD group, n=53, aged 48.6+/-2.9 years) or repeated (postinfarction IHD group, n=32, aged 51.7+/-2.9 years) IHD attack, and had no other causes for the increased heart load. Twenty-nine males of similar age (mean age, 46.0+/-3.1 years) who succumbed to external causes served as controls.
Results: We have found cardiomyocyte hypertrophy in the preinfarction IHD group already. The cardiomyocyte volume was increased by 32.0% in comparison with the same index in the control group, and cross-sectional area and length--by 17.2 and 12.5%, respectively. In postinfarction IHD group, all studied cardiomyocyte parameters did not differ significantly from the analogous indices in the preinfarction IHD group (P>0.05). Cardiomyocyte hypertrophy was related to the increase in left ventricular cardiomyocyte parameters.
Conclusions: Left ventricular cardiomyocyte hypertrophy occurs before the first myocardial infarction. In postinfarction myocardium, cardiomyocyte dimensions do not differ significantly at least prior to the appearance of congestive heart failure syndrome.