Intravenous Amiodarone in Preexcited Atrial Fibrillation: A Systematic Review

The current guidelines contraindicate intravenous amiodarone in patients with Wolff-Parkinson-White syndrome presenting with preexcited atrial fibrillation (AF) due to the risk of degeneration into ventricular fibrillation (VF). However, these recommendations are based predominantly on isolated case reports, which is concerning given the drug's widespread global use as a first-line antiarrhythmic in resource-limited settings. To evaluate the safety of intravenous amiodarone in this context, we conducted a systematic review of (1) studies enrolling patients with electrocardiographically confirmed preexcited AF who received intravenous amiodarone and (2) studies quantifying antegrade accessory-pathway effective refractory period during intravenous amiodarone administration. All observational and interventional studies assessing patients with preexcited AF were pooled under a conjugate β-binomial model with prespecified weak priors to estimate the risk of VF during or following infusion. Concomitantly, to assess real-world access to alternative class IIa/IIb European Society of Cardiology-recommended antiarrhythmic agents for preexcited AF, we performed a multinational survey of Latin American emergency departments. Twelve studies comprising 177 patients were included in the review (7 case reports, 2 cohorts, 3 before-and-after interventional studies). Four case reports described transient ventricular rate acceleration or VF following intravenous amiodarone. However, across the observational and interventional cohorts assessing patients with preexcited AF (n=146), no acceleration or VF was observed. The posterior mean estimates of VF risk ranged 0.12% to 0.68% over priors. Across 3 interventional before-and-after studies, there was a significant increase in the anterograde effective refractory period of the atrioventricular node and AP following amiodarone administration. The survey responses from 10 emergency centers indicated that none had access to class IIa/IIb indicated agents, while all had intravenous amiodarone available. Taken together, population-level evidence suggests that the risk of VF in preexcited AF following intravenous amiodarone administration is rare. In settings where guideline-recommended drugs are inaccessible, intravenous amiodarone may represent a clinically reasonable alternative for rhythm or rate control.