Regional changes in hemodynamics and cardiac myocyte size in rats with aortocaval fistulas. 2. Long-term effects.

Abstract
Regional changes in hemodynamics and cardiac myocyte size were examined in adult rats 5 months after creating a large aortocaval fistula. At that time, cardiac output, left and right ventricular pressures, and left and right ventricular dP/dtmax were measured. Subsequently, isolated cardiac myocytes were collected from the left ventricle, right ventricle, and septum for cell size measurements. Compared with sham-operated controls, percent dry weight was reduced in the liver and kidney but was unchanged in the lung. Heart rate, left ventricular systolic pressure, left ventricular dP/dtmax, and systolic aortic pressure were not changed in rats with fistulas. However, cardiac output, stroke volume, left ventricular end-diastolic pressure, and all measured parameters in the right ventricle were significantly increased. Mean cell volume and the ratio of heart weight to body weight were both elevated 92%. Cell volume, cell length, and cross-sectional area increased significantly in each heart region examined. H...