Cardioversion in Atrial Fibrillation
A patient presents to clinic due to one week of fatigue and palpitations, as well as intermittent episodes of lightheadedness. She is a 70-year-old woman with a history of treated obstructive sleep apnea, hypertension, coronary artery disease, and myocardial infarction three years ago. She has never had a syncopal episode. An EKG is done in clinic, and she is diagnosed with new onset atrial fibrillation. On exam, her heart is irregularly irregular, and her heart rate is in the 70s at rest. She is normotensive and euvolemic on exam.
Recent labs show that her creatinine clearance is 68 mL/min, and her hemoglobin/hematocrit are normal. The patient has concerns with frequent lab testing that would be necessary with warfarin. The decision is made to schedule a cardioversion.
What anticoagulation strategy would be preferred?
The correct answer is: C. Start a non-vitamin K oral anticoagulant and plan for a cardioversion with no TEE in 4 weeks
Answer A is not the best option because the patient does not want frequent blood testing for INR levels. The 2014 AHA/ACC/HRS Guidelines for Atrial Fibrillation emphasize the importance of shared-decision making, incorporating patient preference in the decision for antithrombotic therapy (class I, level of evidence [LOE] C).1 Moreover, since on average warfarin takes a few weeks to result in a stable target INR, answer 1 would probably not be possible due to the need for at least three weeks of a therapeutic INR.
Answers B and D are not the best answers because the patient's symptoms are well-controlled, and her clinical situation does not warrant urgent cardioversion.
The correct answer is C. The patient has a CHA2DS2-VASc score of 4 (hypertension, age 65-74, vascular disease with history of MI, female),2 so she should be treated with chronic oral anticoagulation.1 Patients undergoing cardioversion are at increased risk of thromboembolic events within the first month and especially within 10 days of the procedure.3-5 The mechanisms for this higher risk period appear to be both the restoration of normal sinus rhythm precipitating the embolization of a thrombus that is present and transient atrial stunning resulting in new thrombus formation. Patients tend to be undertreated with anticoagulation around the time of cardioversion in general practice.6 The current AHA/ACC/HRS guidelines recommend that patients with an atrial fibrillation (AF) episode lasting greater than 48 hours should receive warfarin (class I, LOE B) or a non-vitamin K antagonist (apixaban, dabigatran, or rivaroxaban; class IIa, LOE C) for at least three weeks prior to and four weeks after cardioversion, regardless of CHA2DS2-VASc score.1 The European Guidelines for AF from 2012 gave a class I (LOE B) recommendation for warfarin and dabigatran use at least three weeks prior to and four weeks after cardioversion, and no recommendation was made on apixaban or rivaroxaban as the post-hoc analyses for these medications had not yet been published.7
Secondary analyses from the clinical trial of each of the FDA-approved newer oral anticoagulants support using these medications for cardioversion without TEE.8-10
|Study drug||Apixaban 5mg BID||Dabigatran 110mg BID Dabigatran 150mg BID||Rivaroxaban 20mg daily|
|Patients with cardioversion (cardioversions)||540 (743)||1270 (1983)||321 (460)*|
|TEE guided cardioversions||203 (27%)||415 (21%)||Not reported|
|Stroke/systemic embolism within 30 days on warfarin||0 (0%)||5 (0.8%) for 110mg dose 2 (0.3%) for 150mg dose||3 (1.9%)|
|Stroke/systemic embolism within 30 days on study drug||0 (0%)||4 (0.6%)||3 (1.9%)|
|* Includes cardioversion and catheter ablation (79 patients)|
The secondary analysis from RE-LY was the largest cardioversion experience. The use of TEE was more frequent among dabigatran patients (26% for 110mg dose and 24% for 150mg dose) versus warfarin patients (13%), which may have been due to the fact that this was an open-label trial. Even with the greater number of TEEs among dabigatran patients, the incidence of thrombus on TEE was similar between all treatment arms (1.1% for warfarin, 1.2% for dabigatran 150mg, and 1.8% for dabigatran 110mg).10 The use of TEE was evenly distributed among warfarin and study drug patients within ARISTOTLE and ROCKET.8,9
There is an ongoing clinical trial comparing rivaroxaban to warfarin among patients undergoing cardioversion (X-VERT trial; NCT01674647). This is a multinational, prospective, randomized, and open-label comparison of rivaroxaban and vitamin K antagonists in approximately 1,500 cardioversion patients.11 There will be two cardioversion strategies: early cardioversion with TEE and late cardioversion with no TEE. The primary efficacy endpoint is a 100 day composite of stroke, transient ischemic attach, systemic embolism, myocardial infarction, and cardiovascular death. The primary safety endpoint is major bleeding at 100 days. Enrollment of this trial has completed, and the study results are expected later this year, which will provide additional guidance around the use of non-vitamin K antagonists for stroke prevention in cardioversion.
- January CT, Wann LS, Alpert JS, et al. 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol 2014. ;[Epub Ahead of Print]. doi:10.1016/j.jacc.2014.03.021.
- Lip GY, Nieuwlaat R, Pisters R, Lane DA, Crijns HJ. Refining clinical risk stratification for predicting stroke and thromboembolism in atrial fibrillation using a novel risk factor-based approach: the euro heart survey on atrial fibrillation. Chest 2010;137:263-72.
- Berger M, Schweitzer P. Timing of thromboembolic events after electrical cardioversion of atrial fibrillation or flutter: a retrospective analysis. Am J Cardiol 1998;82:1545-7, A8.
- Gallagher MM, Hennessy BJ, Edvardsson N, et al. Embolic complications of direct current cardioversion of atrial arrhythmias: association with low intensity of anticoagulation at the time of cardioversion. J Am Coll Cardiol 2002;40:926-33.
- Airaksinen KE, Gronberg T, Nuotio I, et al. Thromboembolic complications after cardioversion of acute atrial fibrillation - The FinCV study. J Am Coll Cardiol 2013.
- Lip GY, Gitt AK, Le Heuzey JY, et al. Overtreatment and undertreatment with anticoagulation in relation to cardioversion of atrial fibrillation (the RHYTHM-AF study). Am J Cardiol 2014;113:480-4.
- Camm AJ, Lip GY, De Caterina R, et al. 2012 focused update of the ESC Guidelines for the management of atrial fibrillation: an update of the 2010 ESC Guidelines for the management of atrial fibrillation. Developed with the special contribution of the European Heart Rhythm Association. Eur Heart J 2012;33:2719-47.
- Piccini JP, Stevens SR, Lokhnygina Y, et al. Outcomes After Cardioversion and Atrial Fibrillation Ablation in Patients Treated With Rivaroxaban and Warfarin in the ROCKET AF Trial. J Am Coll Cardiol 2013;61:1998-2006.
- Flaker G, Lopes RD, Al-Khatib SM, et al. Efficacy and safety of apixaban in patients after cardioversion for atrial fibrillation: insights from the ARISTOTLE Trial (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation). J Am Coll Cardiol 2014;63:1082-7.
- Nagarakanti R, Ezekowitz MD, Oldgren J, et al. Dabigatran versus warfarin in patients with atrial fibrillation: an analysis of patients undergoing cardioversion. Circulation 2011;123:131-6.
- Ezekowitz MD, Cappato R, Klein AL, et al. Rationale and design of the eXplore the efficacy and safety of once-daily oral riVaroxaban for the prEvention of caRdiovascular events in patients with nonvalvular aTrial fibrillation scheduled for cardioversion trial: A comparison of oral rivaroxaban once daily with dose-adjusted vitamin K antagonists in patients with nonvalvular atrial fibrillation undergoing elective cardioversion. Am Heart J 2014;167:646-52.