The purpose of this study was to investigate the effect of prostaglandin E1 on rabbit heart preservation. The hearts were arrested with cardioplegia (CP) solution, followed by intracoronary infusion of Euro-Collins (E-C) solution. They were immersed in E-C solution at 4-degrees-C for 9 hr, flushed with terminal warm CP solution, and reperfused with oxygenated Tyrodes' solution at 80 mmHg for 90 min. Eighteen rabbits (Kabushikigaishya BioTec Japanese white) were divided into 3 groups. Group I served as the control. In groups II and III, 200 ng/kg/min of PGE1 was given for 30 min before the heart was removed and 5-mu-g was added to the initial CP solution. In group III, 5-mu-g was also added to both E-C solutions and to the terminal CP solution. The values of CPK and LDH in the terminal CP solution and in the coronary effluent in groups II and III were lower, and coronary flow after reperfusion in group III was significantly greater at 5 min and from 60 min until the end of the experiment. Left ventricular maximum dP/dt at each end-diastolic pressure was significantly higher than control in groups II and III. The values of the wet/dry ratio of reperfused hearts in groups II and III were significantly lower than in the control. In conclusion, treatment with PGE, before heart extraction and the addition of PGE1 to both E-C solutions and to the terminal CP solution contributed to superior left ventricular function after reperfusion, by improving preservation and reducing interstitial edema.