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CLINICAL STATEMENTS AND GUIDELINES

Circulation. 2024;149:e1–e156. DOI: 10.1161/CIR.0000000000001193 January 2, 2024 e73

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

step for acute rhythm control. Therefore, in patients with hemodynamically stable AF, electrical cardioversion is favored over pharmacological cardioversion when the patient is able to tolerate sedation, desires more immediate rhythm conversion, or has failed or not met candidacy for pharmacological cardioversion. Monitoring and preparedness during and after electrical cardioversion include monitoring for rare chronotropic, hemodynamic, or thromboembolic complications, and the effects of anesthesia administered during electrical cardioversion.6,13,14,20–22

3 Unsynchronized or inappropriately synchronized

cardioversion can induce VF if the shock energy is delivered during the vulnerable period, the inscription of the T wave.3,23–25 Therefore, electrical cardioversion for AF should be synchronized with the QRS complex. The synchronization feature needs to be turned on or confirmed that it is on; in patients who require multiple shocks, the synchronization feature must be manually activated and/or confirmed before each shock attempt. Visual confirmation of synchronization to QRS is important to detect inappropriate synchronization and ensure appropriate synchronization. 4.	 An earlier small, multicenter, prospective random-

ized study demonstrated higher efficacy of initial electrical cardioversion with a biphasic waveform instead of monophasic waveform.4 A more contemporary single-centered, randomized study of 279 patients who were randomized to synchronized direct current cardioversion with biphasic waveform with either upfront maximum-fixed energy or strategy of low-escalating energy found higher first shock success with maximum-fixed energy (75% compared with 34% for low-escalating energy group).5 In the contemporary RAFF2 study of patients with hemodynamically stable AF of recent onset, the upfront electrical cardioversion group with initial biphasic 200 J shock (and up to 3 consecutive shocks allowed, with higher energy permitted for subsequent shocks) had conversion to sinus rhythm in 176 of 192 (92%) patients in this upfront electrical cardioversion shock-only group.2

5 A previous study of patients with persistent AF

(median AF duration, 5 months) undergoing direct current cardioversion with escalation of energy found the anterior-posterior orientation of the electrode vector more successful at restoring sinus rhythm than an anterior-lateral vector,7 while a subsequent study of patients with recently diagnosed AF (≥3 hours and <7 days) undergoing direct current cardioversion using biphasic upfront 200 J showed similar success rates with electrode vectors in either anterior-posterior or anterior-lateral orientation.2 Taken together, when energy output is optimized as biphasic and maximal output and the AF is of recent onset, either vector orientation may be reasonable, but for patients with longer duration of AF, the anterior-posterior orientation of electrode vector may be favorable.2 Manual pressure augmentation26 or administration of antiarrhythmic drugs as pretreatment (Section 8.2.3, “Pharmacological Cardioversion”)6,8,9 may also facilitate electrical cardioversion. 6.	 Increased body weight has been associated with

reduced success of electrical cardioversion.27 In a small randomized clinical study, use of paddles, manual pressure augmentation (using electrically silent objects as insulator), and further escalation of electrical energy improved success of electrical cardioversion of obese patients with AF,10 and the benefits of these maneuvers may mechanistically relate to overcoming increased transthoracic impedance. Other alternatives in refractory cases include the use of 2 defibrillators simultaneously, effectively doubling the delivered energy.

8.2.3 Pharmacological Cardioversion

Recommendations for Pharmacological Cardioversion Referenced studies that support the recommendations are summarized in the Online Data Supplement. COR LOE Recommendations

2a C-LD 1 For patients with AF, pharmacological cardioversion

is reasonable as an alternative to electrical cardioversion for those who are hemodynamically stable or in situations when electrical cardioversion is preferred but cannot be performed.1

2a A 2 For patients with AF, ibutilide2,3 is reasonable for

pharmacological cardioversion for patients without depressed LV function (LVEF <40%).

2a A 3 For patients with AF, intravenous amiodarone is rea-

sonable for pharmacological cardioversion, although time to conversion is generally longer than with other agents (8-12 hours).4–8

2a A 4 For patients with recurrent AF occurring outside the

setting of a hospital, the “pill-in-the-pocket” (PITP) approach with a single oral dose of flecainide9–11 or propafenone,10–14 with a concomitant atrioventricular nodal blocking agent,15 is reasonable for pharmacological cardioversion if previously tested in a monitored setting.16–18

2b B-R 5 For patients with AF, use of intravenous procainamide

may be considered for pharmacological cardioversion when other intravenous agents are contraindicated or not preferred.19

Synopsis Pharmacological cardioversion is indicated for patients with new-onset or persistent AF that is hemodynamically stable, or in rare instances when electrical cardioversion is desired but contraindicated. Ibutilide works rapidly for pharmacological cardioversion of AF but is associated with QT interval prolongation and torsades de pointes, particularly in patients with HFrEF.2,3,20,21 Data support intravenous amiodarone for pharmacological

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