Heart function and morphology in rats with chronic large myocardial infarction.
Large transmural myocardial infarctions were created in rats by occlusion of the descending branch of the left coronary artery. Four weeks after surgery, parameters of left and right ventricular function and of peripheral circulation were measured in the closed-chest, anesthetized animals and compared with those obtained in sham-operated controls. The morphology of the hearts was examined both at the macroscopic and cell size level. Cardiac output, LVSP, and the LV weight/body weight ratio were markedly lower than in sham-operated controls. LVEDP was elevated up to 32 +/- 2 mm Hg. On the other hand, RVSP, RV dp/dtmax, the right ventricular weight/body weight ratio, and the volume of myocytes isolated from the right ventricular free wall were increased. Histological examination of the lungs revealed marked thickening of the tunica media of small pulmonary arteries with narrowing of the lumen. These changes are considered to represent the morpohological basis for the increased pulmonary vascular resistance which was associated with right ventricular pressure overload and hypertrophy.
Zimmer
H G
HG
Department of Physiology, University of Munich, FRG.
D000818:Animals; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006439:Hemodynamics; D009203:Myocardial Infarction / Q000473:pathology / Q000503:physiopathology*; D009206:Myocardium / Q000473:pathology*; D051381:Rats; D011919:Rats, Inbred Strains