INTRAVENOUS AMIODARONE FOR RECURRENT SUSTAINED HYPOTENSIVE VENTRICULAR TACHYARRHYTHMIAS

Objectives. We sought to determine the response rate and safety of int ravenous amiodarone in patients with ventricular tachyarrhythmias refr actory to standard therapies. Background. Numerous small retrospective reports suggest a response of refractory ventricular tachyarrhythmias to intravenous amiodarone, get no controlled prospective trials exist . Methods. Two hundred seventy-three patients with recurrent hypotensi ve ventricular tachyarrhythmias refractory to lidocaine, procainamide and bretylium were randomized to receive one of three doses of intrave nous amiodarone: 525, 1,050 or 2,100 mg/24 h (mean [+/- SE] dose 743.7 +/- 418.7, 1,175.2 +/- 483.7, 1,921.2 +/- 688.8 mg, respectively) by continuous infusion over 24 h. Results. Of the 273 patients, 110 (40.3 % response rate) survived 24 h without another hypotensive ventricular tachyarrhythmic event while being treated with intravenous amiodarone as a single agent (primary end point). A significant difference in th e time to first recurrence of ventricular tachyarrhythmia (post hoc an alysis) over the first 12 h was observed when the combined 1,050- and 2,100-mg dose groups were compared with the 525-mg dose group (p = 0.0 46). The number of supplemental (150 mg) infusions of intravenous amio darone (given for breakthrough destabilizing tachyarrhythmias) during hours 0 to 6 (prespecified secondary end point) was significantly grea ter in the 525-mg dose group than in the 2,100-mg dose group (1.09 +/- 1.57 vs. 0.51 +/- 0.97, p = 0.0043). However, there was no clear dose response relation observed in this trial with respect to success rate s (primary end point), time to first recurrence of tachyarrhythmia (po st hoc analysis) or mortality (secondary end point) over 24 h, Conclus ions. Intravenous amiodarone is a relatively safe therapy for ventricu lar tachyarrhythmias refractory to other medications.