Myocardial preservation during anoxic arrest. Premedication with propranolol, verapamil or methylprednisolone

Anoxic cardiac arrest was studied for one hour in five groups of dogs. Groups I-III were given methylprednisolone (30 mg/kg b.w.) before aortic cross-clamping. Normothermia was used with electrically induced ventricular fibrillation in group I, and without such fibrillation in group II, while group III was studied in local hypothermia. Propranolol (10 micrograms/kg) was given to group IV and verapamil (0.2 mg/kg) to group V before the anoxic arrest in local hypothermia. Judged from the ability of the heart to take over the circulation after anoxic arrest, local cooling preceded by propranolol or verapamil gave working performance comparable with the pre-arrest values. In the cooled, steroid-pretreated hearts the work capacity was depressed to the same degree as in locally cooled hearts without steroid premedication. Methylprednisolone prevented ischemic contracture during normothermic arrest with induced fibrillation, but not in the absence of such fibrillation. As adjuvant to local cooling, pretreatment with metabolism-reducing drugs is favorable for cardiac performance after arrest. Steroid premedication should be considered when normothermic arrest with electrically induced ventricular fibrillation is planned.