Cardioprotection by molsidomine and iloprost in myocardial ischemia in anaesthetized cats

In ten anaesthetized open chest cats the ligation of left descending coronary artery (LLDCA) resulted in 80 percent of mortality with survival time of 40.9 +/- 8.6 min. The death of animals was preceded by premature ventricular contractions which occurred with frequency 7.3 +/- 0.6/min after 2.1 +/- 0.3 min following LLDCA. Molsidomine as a dose of 20 micrograms/kg given i.v. to 10 cats 15 min before LLDCA affected none of the above characteristics of acute myocardial ischemia. The pretreatment with iloprost (2 micrograms/kg given i.v. to 10 cats) diminished frequency of premature ventricular contractions and elongated a period of time required for their occurrence after LLDCA, however, iloprost was also unable to diminish mortality of LLDCA cats. Only a combined administration of molsidomine and iloprost significantly diminished mortality among LLDCA cats down to 20 percent and doubled their survival time as compared to the controls. It is concluded that NO-donors (molsidomine) exert permissive effect towards the cardioprotective action of prostacyclin analogues (iloprost) in cats with myocardial ischemia. LLDCA cats pretreated with molsidomine + iloprost enjoyed a more complete cardioprotection than those pretreated with a high dose (3000 units/kg i.v.) of superoxide dismutase.