Intravenous amiodarone for acute pharmacological conversion of atrial fibrillation in the emergency department

Esmolol Compared with Amiodarone in the Treatment of Recent-Onset Atrial Fibrillation (RAF): An Emergency Medicine External Validity Study

BACKGROUND

Recent-onset atrial fibrillation (RAF) is the most frequent supraventricular dysrhythmia in emergency medicine. Severely compromised patients require acute treatment with injectable drugs OBJECTIVE: The main purpose of this external validity study was to compare the short-term efficacy of esmolol with that of amiodarone to treat severe RAF in an emergency setting.

METHODS

This retrospective survey was conducted in mobile intensive care units by analyzing patient records between 2002 and 2013. We included RAF with (one or more) severity factors including: clinical shock, angina pectoris, ST shift, and very rapid ventricular rate. A blind matching procedure was used to constitute esmolol group (n = 100) and amiodarone group (n = 200), with similar profiles for age, gender, initial blood pressure, heart rate, severity factors, and treatment delay. The main outcome measure was the percentage of patients with a ventricular rate control defined as heart frequency ≤ 100 beats/min. More stringent (rhythm control) and more humble indicators (20% heart rate reduction) were analyzed at from 10 to 120 min after treatment initiation.

RESULTS

Patient characteristics were comparable for both groups: age 66 ± 16 years, male 71%, treatment delay < 1 h 36%, 1-2 h 29%, > 2 h 35%, chest pain 61%, ST shift 62%, ventricular rate 154 ± 26 beats/min, and blood pressure 126/73 mm Hg. The superiority of esmolol was significant at 40 min (64% rate control with esmolol vs. 25% with amiodarone) and for all indicators from 10 to 120 min after treatment onset.

CONCLUSION

In "real life emergency medicine," esmolol is better than amiodarone in the treatment of RAF.

Efficacy and safety in pharmacological cardioversion of recent-onset atrial fibrillation: a propensity score matching to compare amiodarone vs class IC antiarrhythmic drugs

The acute management of recent-onset (<48 h) atrial fibrillation (AF) is still debated. Aim of our study was to compare efficacy and safety of intravenously administered class IC antidysrhythmic agents vs amiodarone in a propensity score matched series of patients acutely treated for AF in the emergency department. During a 3-year period, we retrospectively evaluated all episodes of recent-onset (<48 h) AF pharmacologically treated for sinus rhythm restoration in the emergency department. By means of a propensity score matching considering the main statistically different covariates, we selected two accurately matched treatment groups. We analysed the differences between amiodarone and class IC group in terms of efficacy and safety that is conversion to sinus rhythm rates within 12 and 48 h after starting treatment, time to conversion, and adverse drug effects. An overall number of 817 episodes of recent-onset AF were collected (amiodarone group = 406, class IC group = 411). After matching, we obtained 358 episodes equally divided (amiodarone group = 179 and class IC group = 179). Conversion rates within 12 h were 139 (53.1 %) in amiodarone group and 95 (72.6 %) in class IC group (p < 0.05). Median time for cardioversion was 420 min (331.6-508.3 CI 95 %) in amiodarone and 55 min (44.9-65.1 CI 95 %) in class IC group (p < 0.05). The incidence of adverse events in both groups was very low and equally distributed (p = ns). Intravenously administration of class IC agents, when compared with amiodarone, proved to be more rapid and effective, and equally safe in the acute management of recent-onset AF.

Intravenous amiodarone for conversion of atrial fibrillation: misled by meta-analysis?

Therapeutic goals for atrial fibrillation (AF) include ventricular rate control, stroke prevention, conversion to normal sinus rhythm, and maintenance of normal sinus rhythm. The optimal strategy of rate versus rhythm control for acute management of patients with AF is a continuing debate. However, selected patients may require acute treatment with antiarrhythmic agents for conversion of symptomatic AF episodes to normal sinus rhythm. Recently published randomized controlled trials, qualitative systematic reviews, meta-analyses, and evidence-based international consensus guidelines have addressed the controversy regarding acute conversion of AF using antiarrhythmic therapy. Although meta-analyses often provide the highest level of evidence, the validity and application of their results are based on the quality of their methodology and accuracy of reporting. Authors of the most recent meta-analysis of amiodarone for conversion of AF state that the drug is effective and relatively rapid acting in converting AF to normal sinus rhythm in a wide range of patients, and they recommend it as a first-line drug. We feel that these conclusions are overstated and potentially misleading due to methodologic limitations of the analysis. The results of this meta-analysis and others concerning acute conversion of AF should be viewed as hypothesis generating and not the definitive answer to this question. Ultimately, well-designed, adequately powered, randomized placebo- or rate-controlled trials are needed in specific patient populations with AF to determine the absolute benefit of intravenous amiodarone for conversion of AF to normal sinus rhythm. Until more data are available, intravenous amiodarone cannot be promoted as a first-line agent for this purpose.