Cardiac myocyte sizes in right compared with left ventricle during overweight and hypertension.

Evidence is sparse concerning hypertrophy of cardiomyocytes in left and right ventricles (LV, RV). LV and RV from 105 forensic autopsies were weighed. Cross sectioned cardiac myocyte thicknesses were measured in hematoxylin and eosin-stained paraffin sections. Overweight (OW) is body weight >104.3 kg and hypertension (HT) is mean arterial pressure >106.7 mm Hg assessed from renal histology. Mean RV weights and cardiomyocyte thicknesses held nearly perfect proportionality to the LV values. Exceptions to these patterns were (1) myocytes were slightly thicker than expected in RV of the 27 specimens with the smallest myocyte thicknesses; (2) weights were slightly greater than expected in RV of hypertensives; and (3) myocytes were slightly smaller than expected in RV of OW subjects. Myocyte hypertrophy appears to affect LV and RV equally, preserving constant proportionality between them in a number of conditions which include OW, HT, and perhaps some cardiomyopathies. Ischemic, valvular, and right ventricular disorders determined at autopsy are specifically omitted from this provisional conclusion. The three exceptions from this principle were of small magnitude and unimpressive statistical significance which calls for cautious interpretation. Neither OW nor HT appears to act predictably upon the heart as exclusively volume or pressure overload.