Effects of 1-(5'-oxohexyl)-3-methyl-7-propylxanthine (HWA 285) on viability of ischemic jeopardized myocardium after acute coronary artery occlusion and reperfusion.

The effects of the xanthine derivative 1-(5'-oxohexyl)-3-methyl-7-propylxanthine (HWA 285) (0.5 mg/kg plus 50 micrograms/kg/min i.v.) on hemodynamics, electrical activity, infarct size, hemorrhage and survival after 90 min occlusion and 30 min reperfusion of one coronary artery were investigated in anesthetized, open-chest dogs in acute experiments. After transient, short-lasting effects prior to coronary artery occlusion the compound did not significantly alter systemic blood pressure, left ventricular pressure, contractility, and the tension-time-index as a measure for myocardial oxygen consumption during coronary artery occlusion and subsequent reperfusion. However, heart rate, left ventricular end-diastolic pressure, and the sum of ST-segment elevation were significantly increased particularly after onset of reperfusion, but the agent prevented severe arrhythmias during vessel occlusion and reperfusion. Infarct size and the amount of hemorrhage after flow release both were significantly smaller in the HWA 285-treated hearts than in saline-treated control hearts (p less than 0.05 in both cases), and the survival rate was higher in the compound group than in the saline controls. These data suggest a cardioprotective effect of HWA 285 in acute canine experiments undergoing coronary artery occlusion and reperfusion, probably due to antiarrhythmic and/or metabolic properties of the compound.