VENTRICULOGRAPHIC EVALUATION IN 3 RAT MODELS OF CARDIAC DYSFUNCTION

Chronic cardiac dysfunction was produced in rats by means of 1) aorto- caval fistula (A-V fistula), 2) coronary ligation, or 3) coronary embo lization. Eleven to twelve weeks later, left ventricular ejection frac tion (LVEF) was evaluated by ventriculography and compared with normal controls. A-V fistula decreased LVEF by 13% and increased cardiac out put (CO) by 82%. Coronary ligation and embolization produced a greater decrease in LVEF (-36% and -30%) and a decrease in CO (-36% and -29%) . Systemic vascular resistance was significantly decreased in the A-V fistula (-47%) model but increased in both ligation and embolization m odels (by 99 and 87%). LV end-diastolic volume was increased in fistul a or ligation (by 68 and 36%), whereas there was no change in rats wit h embolization. LV end-systolic volume and LV end-diastolic pressure w ere significantly increased in all three models. Plasma atrial natriur etic factor was increased by 676% with fistula, 212% with ligation, an d 113% with embolization. There was no significant change in plasma re nin activity or catecholamines in any of the models. We concluded that coronary embolization and ligation are effective methods of producing chronic LV dysfunction in rats, as evidenced by the significant decre ase in LVEF. On the other hand, A-V fistula is an appropriate model of myocardial hypertrophy with greatly increased plasma atrial natriuret ic factor, but cardiac dysfunction was minimal as indicated by the mil d decrease in LVEF.