Abstract 15024: Efficacy of Bretylium in Termination of Treatment Resistant Ventricular Tachycardia and Ventricular Fibrillation

Bretylium is the only drug approved by the FDA specifically to terminate ventricular fibrillation (VF). It has also been approved to treat life threatening ventricular tachycardia (VT) as a second line agent. Due to shortage of drug substance, bretylium became unavailable for clinical use and has been dropped from ACLS guidelines in 2000. Recently, intravenous (IV) bretylium became available again in the U.S. This study evaluated the efficacy of bretylium IV in the termination of treatment resistant VT and VF. In 4 studies, a total of 85 patients with sustained VT and/or VF were administered IV bretylium 5 mg/kg: 23 patients had VT and 62 had VF. Resistant VT/VF was defined as VT or VF that could not be terminated by shock or other anti-arrhythmics or recurred before bretylium was administered. All patients received IV lidocaine; 71 received between 1 to 5 additional antiarrhythmics, and all patients with VF received DC shocks and failed all pharmacologic therapies prior to bretylium administration. Overall, 61 patients (72%) were successfully treated with IV bretylium and 31 survived to discharge from the hospital (36%). A meta-analysis of these studies indicates that the weighted conversion rate across the studies was 70% (see figure). The only study that compared IV bretylium and amiodarone did not find superiority of amiodarone in the suppression of hemodynamically destabilizing VT or VF. In patients with resistant VT or VF bretylium is reported to be effective in acute termination of the VT or VF that otherwise was not responsive to shock or other anti-arrhythmic drugs. These results suggest that bretylium should be employed in the pharmacotherapy of VT and VF when DC shock or other anti-arrhythmic drugs fail. The studies this report is based on are small studies and thus there is a need for a large controlled clinical trial to provide a better understanding of bretyliums effectiveness and if a higher than 30 mg/kg dose of bretylium would be more effective.