Efficacy and safety of short intravenous amiodarone in supraventricular tachyarrhythmias.

The safety and efficacy of short intravenous therapy with amiodarone were evaluated in 44 patients (24 males, 20 females), aged 21-84 years, with supraventricular tachyarrhythmias newly arisen in less than 24 hours. The study group consisted of 15 patients with paroxysmal supraventricular tachycardia, 8 patients with atrial flutter and 21 patients with atrial fibrillation. They were treated with a single infusion of amiodarone up to 2 hours after the restoration of a stable sinus rhythm, or up to a maximum dose of 2400 mg in 24 hours. Our study shows that 88.6% of all supraventricular tachyarrhythmias reverts to sinus rhythm in less than 24 hours: 100% of paroxysmal supraventricular tachycardia, 75% of atrial flutter, and 85.7% of atrial fibrillation. Intravenously administered amiodarone proves to take effect rapidly (0.5 to 22 hours). The plasma amiodarone concentrations at sinus rhythm restoration showed a wide range (405-3800 ng/ml). Piecewise analysis suggested that the probability of sinus rhythm was 14.4-fold greater in paroxysmal supraventricular tachycardia. No linear statistical relationship was detectable between the log-dose-body mass index and log-QTc. Total amiodarone dose and left atrial volume are inversely correlated with a statistically significant difference. The toxicity in our short intravenous course with amiodarone was not relevant. We conclude that short high-dose intravenous amiodarone shows efficacy and safety in all newly occurring supraventricular tachyarrhythmias.