Intravenous Amiodarone for Incessant Tachyarrhythmias in Children

Abstract

Background-Intravenous (IV) amiodarone has proven efficacy in adults. However, its use in children is based on limited retrospective data. Methods and Results-A double-blind, randomized, multicenter, dose-response study of the safety and efficacy of IV amiodarone was conducted in 61 children (30 days to 14.9 years; median, 1.6 years). Children with incessant tachyarrhythmias (supraventricular arrhythmias [nϭ26], junctional ectopic tachycardia [JET, nϭ31], or ventricular arrhythmias [nϭ4]) were randomized to 1 of 3 dosing regimens (low, medium, or high: load plus 47-hour maintenance) with up to 5 open-label rescue doses. The primary efficacy end point was time to success. Of 229 patients screened, 61 were enrolled during 13 months by 27 of 48 centers in 7 countries. Median time to success was significantly related to dose (28.2, 2.6, and 2.1 hours for the low-, medium-, and high-dose groups, respectively; Pϭ0.028). There was no significant association with dose for any arrhythmia subgroup, including JET, but the subgroups were too small for an accurate assessment. Adverse events (AEs) were common (87%), leading to withdrawal of 10 patients. There were 5 deaths in the 30-day follow-up period (2 possibly related to the study drug). Dose-related AEs included hypotension (36%), vomiting (20%), bradycardia (20%), atrioventricular block (15%) and nausea (10%). Conclusions-In children, the overall efficacy of IV amiodarone, as measured by time to success, was dose related but not significantly for any arrhythmia subgroup. AEs were common and appeared to be dose related. Although efficacious for critically ill patients, the dose-related risks of IV amiodarone should be taken into account when treating children with incessant arrhythmias. Prospective, placebo-controlled trials would be helpful in assessing antiarrhythmic drug efficacy in children, because their results may differ from retrospective series and adult studies.

Atrial Fibrillation in Patients with Congenital Heart Disease

“…Amiodarone is effective at controlling incessant postoperative atrial arrhythmias, including junctional ectopic tachycardia. [29] It should be administered with caution in adolescents and children because of its daunting long-term side-effect profile, which includes thyroid dysfunction, pulmonary fibrosis, hepatic dysfunction, and corneal deposition. [30] Patients with CHD are more likely to present with arrhythmias that are refractory to single-drug therapy, demonstrate depressed myocardial function, and have an intolerance of agents with negative inotropic effects.…”

Part 14: Pediatric Advanced Life Support

“…• Consider amiodarone 5 mg/kg IO/IV 308,309 or procainamide 15 mg/kg IO/IV 236 for a patient with SVT unresponsive to vagal maneuvers and adenosine and/or electric cardioversion; for hemodynamically stable patients, expert consultation is strongly recommended prior to administration (Class IIb, LOE C). Both amiodarone and procainamide must be infused slowly (amiodarone over 20 to 60 minutes and procainamide over 30 to 60 minutes), depending on the urgency, while the ECG and blood pressure are monitored.…”

Is It Time to Tell the Emperor He Has No Clothes?

“…Thus, the inferiority of amiodarone may reflect a patient population with intrinsically more difficult-to-treat arrhythmias. Further, the initial loading and maintenance doses of amiodarone (median, 2.5 mg/kg and Ϸ7 mg/kg/d, respectively) were considerably lower than the doses reported to be effective in previous retrospective studies 2 and a prospective randomized trial, 3 in which loading doses are typically 5 mg/kg and maintenance 10 mg/kg/d. However, the doses of procainamide used (median, 10 mg/kg load and 20 g/kg/min maintenance) were comparable to those reported in the literature for acute management of tachyarrhythmias.…”