We hypothesized that intermittent coronary sinus retroperfusion (ICSR) would improve cardiac function after an in situ ischemic insult. To test this, we analyzed the global and regional ventricular function of anesthetized open-chest dogs. The left anterior descending coronary artery (LAD) was occluded for 135 minutes before the animals were killed. ICSR was performed for the 120 minutes (from 5 minutes to 135 minutes after ligation of the LAD) using balloon catheter which is placed at the coronary sinus via right atrium artery. Measurements were performed before, and seven specific times after occlusion of the LAD. Values were expressed as 100% at 15 minutes after LAD ligation. We found that percent recovery of the max volume of the instantaneous pressure-volume ratio (Emax) demonstrated a significant change between the ICSR group (n = 7) and the control group (n = 7) at 60 minutes after the beginning of ICSR (ICSR group: 126.6 +/- 23, control group: 84.5 +/- 40, p < 0.05). Also left ventricular systolic pressure and maximum negative dp/dt improved in ICSR group compared with control group 75 minutes after LAD occlusion (p < 0.01). Other cardiac functions were a trend toward improvement by ICSR though there was no significant difference between any groups. However in the control group, cardiac function was worse after occlusion. We concluded that retrograde perfusion with ICSO improved both global and regional cardiac functions in the acute myocardial infarction.