Efficacy of i.v. amiodarone in converting rapid atrial fibrillation and flutter to sinus rhythm in intensive care patients.

Twenty-six consecutive patients (14 males, 12 females--mean age 66.6) were admitted to an intensive care unit (ICU) because of a rapid ventricular response to atrial fibrillation (RAF). Fourteen of them had been unsuccessfully treated by drugs (other than amiodarone) and/or DC shock before admission. A loading dose of i.v. amiodarone was administered (repeated boluses of 3 mg/kg in 3 min, or 30 min-infusions of 5 to 7.5 mg/kg), followed by continuous infusion, in order to reach a maximal total dosage of 1500 mg in 24 h. This treatment was considered efficacious if a reversion to stable sinus rhythm (SSR) occurred within 24 h and was maintained for more than 48 h. This was achieved in 21 out of 26 patients (80.8%). The mean time between the administration of therapy and the occurrence of SSR was 171 min. The total dose of amiodarone delivered to effect SSR was 6.9 +/- 2.3 mg/kg. No adverse reactions were encountered during the bolus injection but we recommend that continuous infusion be carried out through a central venous catheter to avoid phlebitis. The administration of 7 mg/kg of intravenous amiodarone delivered in 30 min proved a safe and successful first choice of management in atrial fibrillation with a rapid ventricular response.