ImportanceWhether the simultaneous intravenous administration of potassium and magnesium is associated with the probability of spontaneous conversion to sinus rhythm (SCV) in the acute treatment of atrial fibrillation (AF) and atrial flutter (AFL) is unknown.ObjectiveTo assess potassium and magnesium administration and SCV probability in AF and AFL in the emergency department.Design, Setting, and ParticipantsA registry-based cohort study was conducted in the Department of Emergency Medicine of the Medical University of Vienna, Austria. All consecutive patients with AF or AFL were screened between February 6, 2009, and February 16, 2020.InterventionsIntravenous administration of potassium, 24 mEq, and magnesium, 145.8 mg.Main Outcomes and MeasuresThe primary outcome was the probability of SCV during the patient’s stay in the emergency department. Multivariable cluster-adjusted logistic regression was used to estimate the association between potassium and magnesium administration and the probability of SCV.ResultsA total of 2546 episodes of nonpermanent AF (median patient age, 68 [IQR, 58-75] years, 1411 [55.4%] men) and 573 episodes of nonpermanent AFL (median patient age, 68 [IQR, 58-75] years; 332 [57.9%] men) were observed. In AF episodes, intravenous potassium and magnesium administration vs no administration was associated with increased odds of SCV (19.2% vs 10.4%; odds ratio [OR], 1.98; 95% CI, 1.53-2.57). In AFL episodes, in contrast, no association was noted for the probability of SCV with potassium and magnesium vs no administration (13.0% vs 12.5%; OR, 1.05; 95% CI, 0.65-1.69).Conclusions and RelevanceThe findings of this registry-based cohort study on intravenous administration of potassium and magnesium suggest an increased probability of SCV in nonpermanent AF, but not AFL, during a patients’ stay in the emergency department.

Atrial fibrillation (AF) is a globally evolving medical challenge with, currently, 4% prevalence in the European Union’s population [...]

Patients with recurrence of atrial tachyarrhythmia after catheter ablation for atrial fibrillation or atrial flutter constitute a rapidly growing cohort, but study-driven treatment recommendations are lacking. The present study aimed to compare the cardioversion success of ibutilide and amiodarone in patients with post-ablation atrial tachyarrhythmia. We included all episodes of post-ablation atrial tachyarrhythmia in patients treated with either intravenous ibutilide or amiodarone at an academic emergency department from 2010 to 2018. The primary endpoint was the conversion to sinus rhythm. The conversion rates were stratified by arrhythmia type, and multivariable cluster-adjusted logistic regression was used to estimate the effect of ibutilide and amiodarone on cardioversion success, given as the odds ratio (OR) with 95% confidence intervals (95% CI). In total, 109 episodes of 72 patients were analyzed. The conversion rates were 37/49 (76%) for ibutilide and 16/60 (27%) for amiodarone. Compared to amiodarone, ibutilide was associated with higher odds of conversion (multivariable cluster-adjusted OR 5.6, 95% CI 1.3–24.3). The cardioversion success of ibutilide was the highest in atrial flutter (crude OR 19.5, 95% CI 3.4–112.5) and focal atrial tachycardia (crude OR 8.3, 95% CI 1.5–47.2), but it was less pronounced in atrial fibrillation (crude OR 4.5, 95% CI 1.2–17.2). Randomized trials are warranted to confirm our findings.

Objective: In critically ill patients with atrial fibrillation (AF) standard treatment algorithms might not be applicable. Emergency departments (ED) play a crucial role in implementing individualized treatment approaches. The aim of this study was to evaluate the effectiveness of ED cardioversion algorithms based on lactate levels as a surrogate for severity of illness. Design, Setting and Patients: This retrospective study was conducted at the ED of the Medical University of Vienna, Austria, between 2012 and 2022. A consecutive series of 3,535 AF episodes were analyzed. Measurement and main results: The main outcome was cardioversion success depending on serum lactate levels [mmol/L]. Lactate levels were divided into quintiles (lac <1.1, 1.1 - 1.3, 1.4 - 1.7, 1.8 - 2.3 and > 2.3mmol/L) and into two groups using a cut-off of 4mmol/L. Overall CV success decreased with rising lactate levels (79% in lac < 1.1mmol/L vs. 61% in lac > 2.3mmol/L; p < 0.001). For electrical cardioversion [eCV] (n=1,119 cases; sinus rhythm [SR] achieved in 86%) success, no significant difference was seen in relation to lactate levels. However, for medical cardioversion [mCV] (n=759; 67% SR), conversion success decreased with increasing lactate levels (SR: lac < 1.1mmol/L 84% vs. lac > 2.3mmol/L 59%; p < 0.001). Conclusion: Overall cardioversion success was less likely with rising lactate levels; especially medical cardioversion success rates decreased. Therefore, AF in the critically ill may benefit from either electrical cardioversion, treatment of the underlying condition or primary rate control, rather than medical cardioversion attempts.

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