PK 11195, an antagonist of peripheral type benzodiazepine receptors, in doses from 5 to 25 mg/kg i.d. protected in a dose-dependent manner dogs against both early and delayed ventricular arrhythmias induced by 20 min ischemia and against ventricular fibrillation following reperfusion. Thus, peripheral-type benzodiazepine receptors might represent a novel target in the treatment of angina and cardiac ischemia.