P2682Efficacy of acute intravenous therapy with potassium, magnesium and metoprolol in recent-onset atrial fibrillation

Abstract

Background: AF ranks among the most frequent underlying or contributory causes of death and has been increasing in the latest decades. Acute-onset atrial fibrillation is a frequent condition in emergency departments, and patients mostly present highly symptomatic with dyspnea and tachycardia. Intravenous application of electrolytes and beta-blocker have been proposed as beneficial acute therapy in small case reports. Within the HAMBURG-AF study we aimed to evaluate the efficacy of intravenous therapy with potassium, magnesium and/ or metoprolol for cardioversion during initial stay in the emergency department. Methods: The HAMBURG-AF study is a prospective study covering all consecutive patients presenting to the emergency department of a large tertiary care center with recent-onset atrial fibrillation from July 01, 2015, to December 31, 2016. Patients with permanent and longstanding persistent atrial fibrillation were excluded, resulting in a total of 469 patients for the present analysis. While one thirds of the patients received either intravenous potassium or intravenous magnesium alone, one third did not receive any intravenous therapy, and the remaining one third received all three intravenous therapies in combination. Results: A total of 330 cases (70%) were classified as paroxysmal atrial fibrillation. Of these, 72% converted into sinus rhythm during initial hospital stay. In multivariate adjusted logistic regression analyses intravenous acute therapy with magnesium [OR 1.76 (95% CI 1.13-2.75); p=0.013] was strongly associated with conversion in sinus rhythm during initial stay in the emergency department, while the association for beta-blockers was borderline non-significant [OR 1.49 (95% CI 0.96-2.32); p=0.074]. Potassium [OR 1.06 (95% CI 0.69-1.64); p=0.79] and the combination of all three supportive therapies failed to show any association with conversion rates [OR 0.85 (95% CI 0.54-1.33); p=0.48]. Interaction analyses proved that the beneficial effect of intravenous magnesium was independent from baseline values of magnesium, and from existing chronic anti-arrhythmic medication. Conclusion: Intravenous therapy with magnesium seems beneficial with regard to acute conversion in recent-onset paroxysmal atrial fibrillation. With respect to costs, required resources, and side effects simple intravenous therapy with magnesium might be a competitive approach to electric cardioversion. This first prospective report on the efficacy of intravenous supportive therapy paved the way for the first controlled multicenter trial, randomizing recent-onset atrial fibrillation patients for intravenous magnesium versus placebo and amiodaron.