Ventriculographic evaluation in three 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 embolization. Eleven to twelve weeks later, left ventricular ejection fraction (LVEF) was evaluated by ventriculography and compared with normal controls. A-V fistula decreased LVEF by 13% and increased cardiac output (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 models (by 99 and 87%). LV end-diastolic volume was increased in fistula or ligation (by 68 and 36%), whereas there was no change in rats with embolization. LV end-systolic volume and LV end-diastolic pressure were significantly increased in all three models. Plasma atrial natriuretic factor was increased by 676% with fistula, 212% with ligation, and 113% with embolization. There was no significant change in plasma renin 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 decrease in LVEF. On the other hand, A-V fistula is an appropriate model of myocardial hypertrophy with greatly increased plasma atrial natriuretic factor, but cardiac dysfunction was minimal as indicated by the mild decrease in LVEF.