This study examined the impairment in systolic and diastolic performance of both ventricles during pacing-induced myocardial ischemia in 12 men with coronary artery disease. Simultaneous hemodynamic, ECG, and radionuclide angiographic assessments were made: pre pacing (pre-P); intermediate pacing (P-1); maximum pacing (P-2); and immediately after pacing (post pacing (P-P). The prepacing measurements were made with the patient in the supine position and during leg elevation. Pacing produced a leftward and upward shift in the diastolic pressure-volume relation, a progressive decrease in left ventricular (LV) end-diastolic volume (p < 0.003) and right ventricular (RV) end-diastolic volume (p < 0.01), concomitant with an increase in the pulmonary artery wedge pressure (p < 0.004) and the right atrial pressure (p < 0.04). The shift in the LV pressure-volume relation was associated with an initial increase (P-1), followed by a decrease (P-2) in the peak filling rate (p < 0.001). Pacing also resulted in systolic dysfunction: abnormal LV ejection fraction responses in eight patients, LV regional wall motion abnormalities in eight patients, and abnormal RV ejection fraction responses in seven patients. Leg elevation resulted in a 7% increase in cardiac output, a 20% increase in RV end-diastolic volume, a 28% increase in right atrial pressure, a 29% increase in pulmonary artery wedge pressure, and a 10% increase in LV end-diastolic volume (p < 0.05). Thus, the ischemic response to pacing results in systolic and diastolic LV and RV dysfunction, with the diastolic impairment being more frequent than the systolic impairment. © 1986.