Efficacy of intravenous amiodarone as short-term treatment for refractory ventricular tachycardia.

The antiarrhythmic efficacy and safety of intravenous amiodarone were evaluated in 13 patients with recurrent sustained ventricular tachycardia. All patients had been refractory to at least three prior antiarrhythmic agents (mean, 3.3 per patient), and 11 had multiple direct current cardioversions. Intravenous amiodarone suppressed sustained tachycardia in seven patients; the concurrent use of procainamide resulted in suppression in two additional patients. Ventricular tachycardia recurred in three patients, two within 2 hours of initiation of amiodarone. Adverse effects necessitated the discontinuation of amiodarone in one patient because of significant hemodynamic deterioration. The use of intravenous amiodarone was associated with a significant fall in heart rate and cardiac output. Plasma amiodarone levels were high after initial bolus loading but declined to low or less than therapeutic levels within 60 minutes. Thus although we found intravenous amiodarone to be effective in the short-term treatment of refractory ventricular tachycardia, administration of amiodarone can be associated with significant hemodynamic deterioration. The dosing protocol used should be modified to a lower initial bolus and a higher early maintenance infusion rate.