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Essence of this article

Anticoagulation is given before cardioversion and for several weeks afterwards because the procedure is associated with a risk of thromboembolism. Guidelines recommend adequate anticoagulation with either a vitamin K antagonist or dabigatran both before and after cardioversion. The current evidence supporting the use of other novel oral anticoagulants comes from retrospective analyses; however, these agents are now being studied in prospective clinical trials in patients undergoing cardioversion. The first such study has reported positive results with rivaroxaban.

The role of anticoagulation in cardioversion

The electrical or pharmacological disruption of left atrium function during the cardioversion procedure is associated with a 5–7% incidence of thromboembolism, including stroke.397 By contrast, the risk is approximately 1% with adequate anticoagulation.398, 399

Current guidelines recommend ≥3 weeks of adequate anticoagulation before cardioversion390, 400

  • Either with a vitamin K antagonist (VKA), dosed to maintain an international normalized ratio of 2.0–3.0, or a novel oral anticoagulant
  • Unless a transesophageal echocardiogram (TEE) excludes left atrial (LA) or left atrial appendage (LAA) thrombus, in which case cardioversion can be performed immediately with heparin anticoagulation

After cardioversion, anticoagulation with a VKA or a novel oral anticoagulant should be given for ≥4 weeks and may need to be continued indefinitely in some patients.390, 400

European Society of Cardiology recommendations for anticoagulation in patients with non-valvular atrial fibrillation undergoing cardioversion390

Recommendation Grade of evidence
For patients with AF of ≥48 h duration, or when the duration of AF is unknown, OAC therapy (e.g. VKA with INR 2.0–3.0 or dabigatran) is recommended for ≥3 weeks prior to and for ≥4 weeks after cardioversion, regardless of the method (electrical or oral/i.v. pharmacological) IB
In patients with risk factors for stroke or AF recurrence, OAC therapy, whether with dose-adjusted VKA (INR 2.0–3.0) or a novel OAC, should be continued lifelong irrespective of the apparent maintenance of sinus rhythm following cardioversion IB
AF, atrial fibrillation; INR, international normalized ratio; i.v., intravenous; OAC, oral anticoagulant; VKA, vitamin K antagonist.

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The ESC guidelines recommend dabigatran for pre-cardioversion anticoagulation based on a subanalysis of the RE-LY trial because a relatively large number of patients planned for cardioversion were included in the study:401

  • Outcomes among the 1270 patients who underwent cardioversion were similar to the overall population, and were not significantly different between dabigatran and VKA401
  • Subanalyses of the phase III studies of rivaroxaban (ROCKET AF) and apixaban (ARISTOTLE) also indicated similar outcomes to the overall populations in patients receiving cardioversion, but there were relatively few of these patients in these trials402, 403
  • These analyses were limited by their retrospective nature and the lack of TEE data collected at baseline to exclude patients with LA/LAA thrombus, in whom cardioversion is contraindicated389

Owing to the established efficacy and safety profiles of novel oral anticoagulants in patients with atrial fibrillation, in addition to the challenges associated with VKA therapy, clinical studies have been designed to prospectively investigate the use of rivaroxaban and apixaban, as well as edoxaban (which is approved for stroke prevention in Japan for patients with non-valvular atrial fibrillation), compared with VKAs, in patients undergoing cardioversion

  • The X-VeRT trial of rivaroxaban (NCT01674647)18 was designed to reflect guideline-recommended treatment strategies and is the first prospective study of a novel oral anticoagulant to report results in this setting:405
    • X-VeRT was underpowered to provide statistically rigorous results. However, compared with the use of VKA, the estimated risk ratios consistently indicated a trend towards lower incidences of thromboembolic events and major bleeding events in favour of rivaroxaban
    • Based on the X-VeRT data, rivaroxaban appears to be an effective and safe alternative to VKA and may allow more prompt cardioversion
  • The ENSURE-AF study (NCT02072434) of edoxaban and the EMANATE trial of apixaban (NCT02100228) are currently underway and will complete in 2015 and 2016, respectively

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