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CLINICAL STATEMENTS AND GUIDELINES

Circulation. 2024;149:e1–e156. DOI: 10.1161/CIR.0000000000001193 January 2, 2024 e71

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

and the extent of comorbid conditions as risks factors for atrial myopathy.38

3 In patients with AF, detection of intracardiac

thrombus should prompt cancellation of planned cardioversion and institution of therapeutic anticoagulation in anticoagulant-naïve patients. Detection of intracardiac thrombus in patients already on anticoagulation should prompt assessment of compliance, dosing appropriateness, drug absorption, and drug interactions. In patients with thrombus detected despite already being anticoagulated, potential reasons should be investigated, such as nonadherence and drug interaction, which may cause subtherapeutic levels. Switching to an alternate anticoagulant can be considered, although the benefit is uncertain. In anticoagulant-naïve patients, 61.2% had resolution of thrombus on follow-up TEE performed 3 to 12 weeks after initiation of VKA in the CLOT-AF (Retrospective Registry Providing Baseline Data on the Outcome of Left Atrial [LA] or LA Appendage [LAA] Thrombus in Patients With Nonvalvular Atrial Fibrillation [AF] or Atrial Flutter After Standard of Care [SoC] Anticoagulant Therapy) study, and 41.5% had resolution of thrombus on follow-up TEE performed 6 weeks after therapy with rivaroxaban in the X-TRA (Exploring the Efficacy of Once Daily Oral Rivaroxaban for Treatment of Thrombus in Left Atrial/Left Atrial Appendage in Subjects With Nonvalvular Atrial Fibrillation or Atrial Flutter) study.8 Repeat imaging (TEE or computed tomography32–34) is generally pursued after at least 3 to 6 weeks of therapeutic anticoagulation to assess for resolution of intracardiac thrombus before reconsidering cardioversion.1,8

4 In the subset of patients who have undergone

surgical or pLAAO procedures, inadequate occlusion may be seen acutely during the procedure or delayed after the procedure.9–14 Inadequate LAAO has been associated with elevated risks for thromboembolism.9–11 Device-related thrombosis, reported in patients with pLAAO devices,15–19 has also been associated with elevated stroke/systemic embolism.15–18 Imaging with TEE or cardiac computed tomography can assess adequacy of LAAO, residual leak, and device-related thrombosis.39–41 In the setting of transesophageal echocardiographic imaging before electrical cardioversion, device-related thrombus was detected in 2.7% (4 of 148 patients) of a small multicenter retrospective analysis of patients with Watchman LAAO device.20 These 4 patients were treated with oral anticoagulation and after 6 to 8 weeks, on confirmation of thrombus resolution by repeat TEE, underwent successful electrical cardioversion.20 5 Data are limited to guide pericardioversion antico-

agulation in patients with LAAO. In the broader (not limited to cardioversion) context, residual leak ≤5 mm by computed tomography after LAAO by surgical ligation has been associated with particularly elevated stroke/system embolism risks (especially in the absence of anticoagulation)9 and similarly for residual leak <5 mm by TEE post-Lariat.10 A large analysis that stratified National Cardiovascular Data Registry LAAO registry Watchman 2.5 device patients by transesophageal echocardiographic observation of residual leak (none, ≤5 mm, >5 mm) at 45 days, found ≤5 mm residual leak to be common (13 258 of 51 333 patients; 25.8%) and associated with modestly higher incidence of thromboembolic events over 1-year follow-up compared with no leak.11 OAC use was more frequent in patients with large (>5 mm) residual leak.11 Data specific to the setting of cardioversion are further limited. The largest to date is a retrospective multicenter study of 148 Watchman LAAO device patients who underwent electrical cardioversion after precardioversion exclusion of intracardiac thrombus or large residual leak (≥5 mm in this study) by TEE.20 No thromboembolic events were observed within 6 weeks of cardioversion, in recipients or nonrecipients of pericardioversion anticoagulation.20 However, detection of thromboembolic events may be limited by study’s sample size. Pericardioversion antithrombotic regimen was at the discretion of the treating physicians,20 and the relationship of anticoagulation with presence/ absence of small residual leak was not reported. Considerations for anticoagulation may also vary based on specific surgical or pLAAO procedures and devices. 6.	 The safety of cardioversion without further assess-

ment or previous anticoagulation in patients with AF duration of <48 hours has been challenged. In addition to concerns for underestimation of actual duration of episode and burden due to potential for asymptomatic occurrence of AF, emerging data demonstrate that thromboembolic risks in patients with <48 hours of AF were not homogenously low. Time to cardioversion >12 hours has been reported as an independent predictor for thromboembolic complications.21 A single-center observational study of patients undergoing cardioversion for AF of <48 hours duration did not observe thromboembolic events in patients with CHA2DS2- VASc score of 0 or 1 or patients with postoperative AF but noted differential thromboembolic rates in CHA2DS2-VASc score ≥2.42 Larger studies similarly demonstrated that among patients with <48 hours of AF, postcardioversion thromboembolic risks increased with increasing CHA2DS2-VASc

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