Management or new onset atrial fibrillation in critically unwell adult patients: a systematic review and narrative synthesis

Background: New onset atrial fibrillation (NOAF) is the most common arrhythmia affecting critically unwell patients. NOAF can lead to worsening haemodynamic compromise, heart failure, thromboembolic events, and increased mortality. The aim of this systematic review and narrative synthesis is to evaluate the non-pharmacological and pharmacological management strategies for NOAF in critically unwell patients. Methods: Of 1782 studies, 30 were eligible for inclusion, including 4 RCTs and 26 observational studies. Efficacy of direct current cardioversion, amiodarone, beta-adrenergic receptor antagonists, calcium channel blockers, digoxin, magnesium, and less commonly used agents such as ibutilide are reported. Results: Cardioversion rates of 48% were reported for direct current cardioversion; however, re-initiation of NOAF was as high as 23.4%. Amiodarone was the most commonly reported intervention with cardioversion rates ranging from 18% to 96% followed by beta-antagonists with cardioversion rates from 40% to 92%. Amiodarone was more effective than diltiazem (odds ratio [OR]=1.91, P=0.32) at cardioversion. Short-acting beta-antagonists esmolol and landiolol were more effective compared with diltiazem for cardioversion (OR=3.55, P=0.04) and HR control (OR=3.2, P<0.001). Conclusion: There was significant variation between studies with regard to the definition of successful cardioversion and heart rate control, making comparisons between studies and interventions difficult. Future RCTs comparing individual anti-arrhythmic agents, in particular magnesium, amiodarone, and beta-antagonists, and studying the role of anti-coagulation in critically unwell patients are required. There is also an urgent need for a core outcome dataset for studies of new onset atrial fibrillation to allow comparisons between different anti-arrhythmic strategies.