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CLINICAL STATEMENTS AND GUIDELINES

Circulation. 2024;149:e1–e156. DOI: 10.1161/CIR.0000000000001193 January 2, 2024 e75

Joglar et al 2023 Guideline for the Diagnosis and Management of Atrial Fibrillation

stable patients with AF who presented to an emergency department, the incidence of successful cardioversion was higher in the direct current cardioversion group (78.2%) than in those who underwent pharmacological conversion (59.2%) or those for whom a “wait-and-watch” approach (37.9%) was used (P<0.001).1 Compared with the “wait-and-watch” strategy, the ORs for conversion to sinus rhythm for direct current cardioversion and pharmacological cardioversion were 6.00 (95% CI, 3.38-10.66) and 2.47 (1.45-4.20), respectively (P<0.001). Due to the potential greater efficacy of direct current cardioversion compared with that of pharmacological cardioversion, and due to the need for rapid successful conversion to sinus rhythm, immediate electrical cardioversion is generally the favored option, yet some patients may not be candidates (eg, cannot undergo anesthesia), for whom pharmacological options are available.31

2 Randomized, double-blind placebo-controlled stud-

ies have established the efficacy of ibutilide2,3 for conversion of AF to sinus rhythm, with AF conversion rates of about 30% (compared with 2% in placebo groups).2,3 The efficacy of ibutilide is greater for AFL (conversion rates, 38%-63%) than for AF.2,3 Ibutilide terminates AF rapidly, with most patients converting to sinus rhythm within 30 to 90 minutes (Table 22). Ibutilide is associated with a risk of QT interval prolongation and torsades de pointes. The incidence of torsades de pointes associated with ibutilide is higher in patients with reduced LVEF than in those with normal LVEF,2,3 and the risk seems particularly high in patients with severely depressed LVEF.20 HFrEF is an independent risk factor for ibutilide-associated torsades de pointes.3,21 Therefore, ibutilide is best avoided in patients with LVEF ≤40%. Of note, studies have shown that a magnesium infusion immediately before administration of ibutilide may mitigate the risk of torsades de pointes and excessive QT prolongation.32,33

3 Multiple randomized studies have found intrave-

nous amiodarone to be effective for conversion of AF to sinus rhythm.4–7 A meta-analysis of randomized, placebo-controlled studies reported relative risks of sinus rhythm associated with intravenous amiodarone at 6 to 8 hours and at 24 hours of 1.23 (P=0.022) and 1.44 (P<0.001), respectively.8 However, pharmacological cardioversion of AF with intravenous amiodarone requires 8 to 12 hours, compared with a much shorter response time with ibutilide (Table 22).

Figure 22. Treatment Algorithm for Pharmacological Conversion of AF to Sinus Rhythm. *In the absence of preexcitation. †First dose administered in a facility that can provide continuous electrocardiographic monitoring and cardiac resuscitation because of the potential for proarrhythmia or postconversion bradycardia. ‡IV amiodarone requires several hours for efficacy; ibutilide is generally effective in 30 to 90 min but carries a higher risk of QT interval prolongation and torsades de pointes. §Recommend avoidance of IV procainamide for patients initially treated with amiodarone or ibutilide to avoid excessive QT interval prolongation and torsades de pointes. Rather, procainamide may be considered for patients for whom amiodarone and ibutilide are not considered optimal as first-line drugs. Colors correspond to Table 2. AF indicates atrial fibrillation; HFrEF, heart failure with reduced ejection fraction; IV, intravenous; LV, left ventricular; LVEF, left ventricular ejection fraction.

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