Abstract Fifty cardiac catheterizations were performed in 44 patients undergoing evaluation for coronary artery disease. Ventricular function curves (VFC) were constructed by plotting the left ventricular end-diastolic pressure (LVEDP) and stroke work index (SWI) before and three to four minutes after a standard left ventricular angiogram. In an attempt to delineate the mechanism that produces changes in the post-angiogram LVEDP and SWI, 13 individuals (Group A) with no evidence of cardiac disease were compared to 14 patients with severe coronary artery disease (Group B). Cardiac output and LVEDP increased in both groups after angiogram. The increase in cardiac output was less and the increase in LVEDP greater in Group B. V max. did not change significantly after angiogram in either group. Other measures of contractility (dpdt max., peak Vce, and dp/dt/40 mm. developed pressure) changed appropriately for the large changes in preload seen after angiogram. Thirty-seven studies in patients with coronary artery disease demonstrated that VFC obtained from the cardiac response to contrast are more sensitive than resting LVEDP or ejection fraction in detecting left ventricular abnormality. VFC can be obtained from the ventricular response to angiographic contrast because of the increase in venous return produced by the hyperosmotic effect of contrast. Depressed curves occur in patients with coronary artery disease because of their stiff ventricles and not because of depression of myocardial contractility.