Use of potassium canrenoate to suppress ouabain-induced ventricular arrhythmias in dogs.

Potassium canrenoate, a steroidal compound and a specific antagonist of aldosterone, had (1) a potent protective effect against ouabain-induced ventricular tachycardia in intact closed-chest dogs and (2) a potent antiarrhythmic effect in abolishing ventricular bigeminy and ventricular tachycardia due to ouabain intoxication in dogs. Conversion of ouabain-induced arrhythmias was usually associated with an improvement in atrioventricular conduction, but no significant alterations in blood pressure or myocardial contractility occurred. Equivalent doses of potassium chloride failed to delay the occurrence of or to abolish the ouabain-induced ventricular tachycardia. Therefore, the antiarrhythmic activity of potassium canrenoate does not seem to be related to the potassium ion in the molecule. Since the compound combines both antiarrhythmic and diuretic activity, potassium canrenoate may be a valuable clinical agent for patients on digitalis therapy.