Prophylactic treatment of swine with bretylium for experimental cardiac catheterization.

We evaluated a cryothermic ablation catheter for potential use in treating supraventricular tachycardia by cardiac catheterization in miniature swine. Cardiac catheterization was performed on anesthetized miniature swine by using multiple catheters that were inserted bilaterally by either percutaneous or cutdown techniques into the femoral veins. We performed electrophysiologic tests according to standard atrial and ventricular electrical stimulation protocols. Manipulation of catheters in the tricuspid valve area and right ventricle was an essential part of the study. During an initial study of five swine, catheter manipulation produced sustained and nonsustained ventricular tachycardia and ventricular fibrillation. To prevent arrhythmias, bretylium (5 mg/kg) was administered intravenously 10 minutes before catheter manipulation and repeated every 30 minutes throughout the procedure. Since the use of bretylium was instituted, there have been no cases of ventricular fibrillation in a series of 20 animals. We determined that bretylium is effective in the suppression of ventricular arrhythmias in swine undergoing cardiac catheterization.