7/6/23, 2:49 PM Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation - UpToDate Official reprint from UpToDate www.uptodate.com 2023 UpToDate, Inc. and/or its affiliates. All Rights Reserved. Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation : Rod Passman, MD, MSCE : Bradley P Knight, MD, FACC, N A Mark Estes, III, MD : Nisha Parikh, MD, MPH All topics are updated as new evidence becomes available and our peer review process is complete. Literature review current through: Jun 2023. This topic last updated: May 05, 2022. INTRODUCTION Ischemic stroke and systemic embolization are major causes of death and disability in patients with atrial fibrillation (AF). This topic will focus on the role of anticoagulant therapy to prevent embolization in patients scheduled to undergo catheter ablation (CA). The role of anticoagulant therapy in the broad population of patients with AF is discussed separately. (See "Atrial fibrillation in adults: Use of oral anticoagulants".) Other aspects of CA are discussed elsewhere. (See "Atrial fibrillation: Catheter ablation" and "Maintenance of sinus rhythm in atrial fibrillation: Catheter ablation versus antiarrhythmic drug therapy" and "Overview of catheter ablation of cardiac arrhythmias" and "Patient education: Catheter ablation for the heart (The Basics)" and "Catheter ablation for the treatment of atrial fibrillation: Technical considerations for non-electrophysiologists".) OUR APPROACH TO ANTICOAGULATION There are three periods when a decision or decisions have to be made about anticoagulation in a patient scheduled for catheter ablation (CA). Preprocedural We effectively anticoagulate most patients, irrespective of CHA DS -VASC 2 2 score ( table 1) or presence or absence of sinus rhythm, with either a vitamin K antagonist (VKA) or a direct oral anticoagulant (DOAC; also referred to as non-vitamin K oral https://www.uptodate.com/contents/catheter-ablation-to-prevent-recurrent-atrial-fibrillation-anticoagulation/print 1/21 7/6/23, 2:49 PM Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation - UpToDate anticoagulants [NOAC]) for at least three weeks prior to CA. It is reasonable to not use preprocedural anticoagulation in AF patients in sinus rhythm (and who are likely to remain in sinus rhythm for three weeks prior to the procedure) with a CHA DS -VASC score of 0. 2 2 (See 'Preprocedural issues' below.) Periprocedural We continue VKA in the periprocedural period. For most patients taking once-a-day DOACs, we hold the dose the day before and the morning of the procedure. For twice-a-day DOACs, some of our experts hold both doses the day before the procedure while others hold only the evening dose before the procedure; no drug is given the morning of the procedure. Uninterrupted DOAC may be reasonable for the uncommon patient who is at very high risk of a periprocedural stroke. Studies support the fact that uninterrupted DOACs may be superior to uninterrupted warfarin for patients who require continued anticoagulation due to high risk of thromboembolism. All patients receive a continuous infusion of unfractionated heparin (UFH); the activated clotting time is maintained at greater than 300 seconds during the procedure. (See 'Periprocedural issues' below.) Postprocedural UFH is stopped at the end of the procedure and the sheaths are pulled when the activated clotting time is <180 to 200 seconds. For patients previously taking a VKA, the next dose is given approximately 24 hours after the prior dose. For those patients in whom the international normalized ratio was <2.0 prior to the procedure, we restart UFH without a bolus six hours after sheath pull, increase the oral warfarin the night of the procedure, and we continue UFH until the INR is 2.0. Another reasonable approach is to stop UFH the morning after the procedure and start low molecular weight heparin, usually at half the normal dose (0.5 mg/kg twice daily) to avoid bleeding. (See 'Postprocedural anticoagulation' below.) For patients previously taking a DOAC, we suggest restarting it - six hours after sheath removal (and in the absence of any related bleeding). Some experts give intravenous heparin (no bolus; drip at 1000 to 1200 units per hour) or low molecular weight heparin (enoxaparin 0.5 mg/kg) starting six hours after sheath pull, that is uncomplicated by bleeding, and continue until the morning after the ablation. Other experts no longer give a heparin after sheath pull. Long-term We continue oral therapy with the previously prescribed oral anticoagulant for two to three months regardless of CHA DS -VASc score. After this period, the decision 2 2 to continue on long-term anticoagulation is based on the patients underlying stroke risk regardless of whether rhythm control has been achieved. For those patients whose risk for https://www.uptodate.com/contents/catheter-ablation-to-prevent-recurrent-atrial-fibrillation-anticoagulation/print 2/21 7/6/23, 2:49 PM Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation - UpToDate embolization is very low, such as those with a CHA DS -VASc score of 0 ( table 1), we stop 2 2 anticoagulation at the two-to-three-month visit. INCIDENCE, TIMING, AND MECHANISM OF EMBOLISM The risk of stroke, transient ischemic attack, or other manifestation of embolization is increased at the time of catheter ablation (CA) and is in the range of 0.4 to 2.0 percent [1-3]. These rates come from studies of patients who are receiving anticoagulant therapy and would be higher off such treatment. Most strokes occur within 24 to 48 hours after the procedure [3]. However, embolic events thought attributable to the procedure have been reported to occur for up to one week [4]. The following are potential causes of periprocedural embolization: Withdrawal of anticoagulation before the procedure Catheter manipulation within the left atrium, which may dislodge preexisting thrombus Catheter trauma to the left atrial endothelium, which increases the risk of thrombus formation Thrombus formation on the ablation catheters or left atrial guide sheaths Conversion to sinus rhythm during the procedure in some patients (see "Prevention of embolization prior to and after restoration of sinus rhythm in atrial fibrillation") Asymptomatic embolism Not all emboli to the brain are symptomatic. Multiple magnetic resonance imaging (MRI) studies performed within 24 hours after CA have demonstrated new cerebral lesions in 7 to 44 percent of asymptomatic patients [5-10]. These lesions are presumed secondary to microemboli [11]. Studies of the subsequent impact of these lesions on neurocognitive function have come to somewhat differing conclusions as to the significance of these lesions: The prevalence of cognitive impairment after radiofrequency CA (RFA) was evaluated in a study of 150 patients: 60 undergoing ablation for paroxysmal atrial fibrillation (AF), 30 for persistent AF, 30 for supraventricular tachycardia, and 30 matched AF patients awaiting RFA (the control group) [12]. All CA patients received periprocedural enoxaparin and most patients with AF had a CHADS score of 0 or 1 ( table 1). All patients underwent eight 2 neuropsychological tests at baseline and at 2 and 90 days after RFA. The prevalence of neurocognitive dysfunction at day 90 was 13, 20, 3, and 0 percent, respectively, in these four groups of patients. https://www.uptodate.com/contents/catheter-ablation-to-prevent-recurrent-atrial-fibrillation-anticoagulation/print 3/21 7/6/23, 2:49 PM Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation - UpToDate In a study of 37 patients with paroxysmal AF who underwent 41 CA procedures, MRI performed within 48 hours showed new brain lesions in 41 percent of patients and 44 percent of procedures [8]. Follow-up MRI at six months found glial scar in about 12 percent of those with lesions. However, there was no decline of neurocognitive function on testing performed after six months. PREPROCEDURAL ISSUES All patients not at low risk of stroke should be treated with long-term anticoagulant therapy using one of the novel oral anticoagulants or warfarin. Thus, many patients will be receiving anticoagulation when scheduled for catheter ablation (CA) and should continue their anticoagulant. (See "Atrial fibrillation in adults: Use of oral anticoagulants", section on 'Summary and recommendations'.) For patients not taking long-term anticoagulant therapy due to a low risk of stroke, there are no studies that have compared differing anticoagulant strategies prior to CA; thus, the optimal preprocedural anticoagulation strategy is not known. For these patients, including those in sinus rhythm, most of our experts carry out a minimum of three weeks of effective oral anticoagulation prior to the procedure. The rationale for doing so is that many episodes of atrial fibrillation (AF) are asymptomatic and these episodes will have placed the patient at risk of embolization at the time of catheter manipulation. We also believe it is reasonable to not use preprocedural anticoagulation in AF patients in sinus rhythm (and who are likely to remain in sinus rhythm for three weeks prior to the procedure) with a CHA DS -VASc score of 0. 2 2 When three weeks of effective anticoagulant therapy has not been carried out, preprocedural transesophageal echocardiography (TEE) should be performed (see 'Role of transesophageal echocardiography' below); patients with evidence of left atrial thrombus are not candidates for CA unless it resolves with anticoagulation. Choice of anticoagulant For patients started on oral anticoagulant therapy prior to catheter ablation, we prefer one of the direct oral anticoagulants (DOAC; also referred to as non-vitamin K oral anticoagulants [NOAC]) group to warfarin. This preference is based on our preference for these agents in the general AF population. (See "Atrial fibrillation in adults: Selection of candidates for anticoagulation".) Most but not all observational studies comparing one NOAC to warfarin have found similar efficacy [13] and safety [14-21]. At least three meta-analyses of observational studies comparing https://www.uptodate.com/contents/catheter-ablation-to-prevent-recurrent-atrial-fibrillation-anticoagulation/print 4/21 7/6/23, 2:49 PM Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation - UpToDate warfarin to dabigatran have come to similar conclusions [22-24]. A 2016 meta-analysis of 25 studies (11,686 patients) comparing DOACs with uninterrupted VKAs found no significant difference in the rate of stroke or transient ischemic attacks (odds ratio 1.35, 95% CI 0.62-2.94) and major bleeding (odds ratio 0.80, 95% CI 0.65-1.00) [25]. Switching oral anticoagulant As stated directly above, we prefer one of the DOAC group to warfarin for patients undergoing catheter ablation. For patients receiving long-term warfarin therapy, there is no evidence that switching to DOAC prior to catheter ablation improves outcomes. Thus, we do not switch from warfarin to an DOAC. We do not have a preference for one DOAC over another and thus we do not switch DOAC. Based on the evidence presented above that suggests that uninterrupted dabigatran is superior to uninterrupted warfarin, we switch patients from warfarin to dabigatran. Role of transesophageal echocardiography Most patients, including those with effective preprocedural oral anticoagulation, should have a TEE performed prior to (generally the day before) CA. The presence of left atrial thrombus is a contraindication to the procedure [26,27]. Transthoracic echocardiography is not a replacement for TEE in this setting. Two reasons to perform TEE prior to (generally the day before) CA are that it adds significant length to the CA, and some complications of TEE, such as a retropharyngeal hematoma, can be aggravated by the unfractionated heparin used during the procedure. (See "Echocardiography in detection of cardiac and aortic sources of systemic embolism", section on 'LA/LAA thrombi'.) We acknowledge that some experts will omit a TEE in the lowest-risk patients who have been taking effective anticoagulant therapy for at least three weeks, such as those in sinus rhythm who have no significant structural heart disease or those with a CHA DS -VASc score of 0 2 2 ( table 1) [27]. These experts often prefer that a pre-ablation magnetic resonance image confirms the absence of left atrial appendage thrombus in these patients who do not undergo preprocedural TEE. In a study of 97 patients undergoing pulmonary vein isolation, contrast- enhanced MRI demonstrated 100 percent concordance with TEE for the presence and absence of left atrial appendage thrombus [28,29]. An attempt to determine the need for preprocedural TEE in patients at low risk for embolization was made in an analysis of 1058 patients who had TEE performed within 24 hours of pulmonary vein isolation [30]. The frequency of left atrial thrombus or sludge was evaluated according to the CHADS score. (See "Echocardiography in detection of cardiac and aortic sources of systemic 2 embolism".) A CHADS score of 0 was present in 47 percent of patients. Left atrial or left atrial 2 appendage thrombus or sludge was found in 0.6 and 1.5 percent of all patients and the https://www.uptodate.com/contents/catheter-ablation-to-prevent-recurrent-atrial-fibrillation-anticoagulation/print 5/21 7/6/23, 2:49 PM Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation - UpToDate frequency increased with ascending CHADS scores (percents in parentheses): 0 (0), 1 (2), 2 (5), 3 2 (9), 4 to 6 (11). We do not use intracardiac echocardiography or computed tomography as a substitute for TEE. Each of these has been shown to be inferior in this setting [31,32]. PERIPROCEDURAL ISSUES The two principal periprocedural anticoagulant issues are how to manage the oral anticoagulant and whether/how to use parenteral anticoagulant. Management of oral anticoagulants For patients taking long-term oral anticoagulant who present for catheter ablation, the approach depends on which anticoagulant the patient has been taking. Patients taking long-term vitamin K antagonist For patients taking a VKA prior to catheter ablation, we prefer the strategy of uninterrupted VKA to a strategy of a heparin bridge. We do not hold doses of VKA unless the international normalized ratio (INR) is >3.0. (See "Perioperative management of patients receiving anticoagulants", section on 'Bridging anticoagulation'.) One randomized trial [33] and most observational studies [3,34,35] have shown that continuous anticoagulation with warfarin, compared with warfarin discontinuation with a heparin bridge, is associated with a lower rate of embolization and an equivalent or lower bleeding rate [36]. In the COMPARE trial, 1584 patients with paroxysmal or persistent atrial fibrillation (AF) (see "Atrial fibrillation: Overview and management of new-onset atrial fibrillation", section on 'Classification and terminology') and CHADS score 1 were randomly assigned to warfarin discontinuation two 2 to three days before ablation and bridging with low molecular weight heparin (1 mg/kg enoxaparin twice daily until the evening before the procedure) or continuation of therapeutic warfarin (three to four weeks with an INR 2.0 to 3.0) [33]. The primary end point of the incidence of thromboembolic events (stroke, transient ischemic attack, or systemic thromboembolism) in the 48 hours after ablation occurred more frequently with warfarin discontinuation (4.9 versus 0.25 percent; odds ratio 13, 95% CI 3.1-55.6). The incidence of major bleeding complications was similar in the two groups (0.76 versus 0.38 percent, respectively). The majority of events occurred in patients with persistent AF. One limitation of the trial is that operators were not blinded to the anticoagulation strategy. For patients in whom a strategy of continuous anticoagulation with warfarin has been chosen, the optimal immediate-preprocedural range for the INR is not known. In a retrospective study of https://www.uptodate.com/contents/catheter-ablation-to-prevent-recurrent-atrial-fibrillation-anticoagulation/print 6/21 7/6/23, 2:49 PM Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation - UpToDate 1113 patients undergoing radiofrequency catheter ablation for AF, bleeding and vascular complications were less prevalent when the INR was 2.0 and 3.0 (5 percent), compared with 2.0 (10 percent) or 3.0 (12 percent) [37]. The optimal INR range was calculated to be 2.1 to 2.5. Patients taking DOACs In most studies that have evaluated periprocedural outcomes in patients taking direct oral anticoagulants (DOAC; also referred to as non-vitamin K oral anticoagulants [NOAC]), the DOAC was held prior to the procedure. In one trial, 326 patients undergoing AF ablation were randomized to uninterrupted DOAC, procedure day single-dose skipped DOAC, or 24-hour skipped DOAC [38]. The intraprocedural heparin dose was higher in the 24-hour skipped group, but the incidence of major bleeding and postprocedural hemoglobin levels were not significantly different among the treatment groups and different DOACs. There were no fatal events or thromboembolic complications. For most patients taking once-a-day DOACs in the morning, we hold the dose the day before and also the day of the procedure. For those that take once-a-day DOACs with the evening meal or later, we hold only a single dose the day before the procedure. For twice-a-day DOACs, some of our experts hold both doses the day before the procedure while others hold only the evening dose before the procedure and the morning of the procedure. For a small minority of patients, such as those at particularly high risk of a periprocedural stroke, including those with a high CHA DS -VASc score in whom intraprocedural cardioversion is 2 2 planned, no interruption of (continuous) oral anticoagulation with a DOAC is a reasonable alternative to interruption. (See 'Choice of anticoagulant' above.) Small randomized trials of dabigatran, rivaroxaban, edoxaban, and apixaban suggest that outcomes with uninterrupted DOACs are similar to those with uninterrupted warfarin [39-42]. Use of intravenous heparin As catheter ablation (CA) is associated with an increase (from baseline) in the risk of a periprocedural thromboembolic event, we recommend that all patients receive intraprocedural heparin. (See 'Incidence, timing, and mechanism of embolism' above.) We start with a loading dose of 100 units/kg at the beginning of the procedure. Others start the loading dose before transeptal puncture, while others give half the dose before and half the dose after transeptal puncture [43]. A continuous infusion is used to maintain the activated clotting time greater than 300 seconds; the first activated clotting time is performed 10 to 15 minutes after the loading dose. Heparin is stopped at the end of the procedure and the sheaths are pulled when the activated clotting time is <180 to 200 seconds. Protamine can be given after the procedure before removing vascular sheaths. https://www.uptodate.com/contents/catheter-ablation-to-prevent-recurrent-atrial-fibrillation-anticoagulation/print 7/21 7/6/23, 2:49 PM Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation - UpToDate Intracardiac echocardiography is done at the end of the CA procedure to ensure that there is no pericardial effusion. If a pericardial effusion is found we take the following approach: For small effusions, we observe and continue with the anticoagulation protocol. If moderate, we reverse anticoagulation and observe. If large, we reverse anticoagulation and perform pericardiocentesis. (See "Diagnosis and treatment of pericardial effusion", section on 'Treatment'.) For patients with hemodynamic compromise, regardless of the size of the effusion, we perform pericardiocentesis and reverse anticoagulation. POSTPROCEDURAL ANTICOAGULATION The approach to anticoagulation within the first 24 hours after a successful procedure is determined in large part by preprocedural anticoagulant approach (see 'Preprocedural issues' above). There have been no studies comparing one approach to another. In the absence of any related bleeding, we suggest the following approach: For those previously taking warfarin, and for whom the management of the international normalized ratio was not problematic, we suggest continuing warfarin. The first postprocedural dose should be the day after the procedure, assuming a dose was given the morning of the procedure. (See 'Patients taking long-term vitamin K antagonist' above.) For patients taking warfarin whose procedure was done with a subtherapeutic international normalized ratio, we restart intravenous heparin without a bolus six hours after sheath pull and start low molecular weight heparin the morning after the procedure. Low molecular weight heparin is continued until the international normalized ratio is therapeutic. When low molecular weight heparin is used, some of our experts give the first dose at 50 percent. For patients previously taking a direct oral anticoagulant (DOAC; also referred to as non- vitamin K oral anticoagulants [NOAC]), DOAC may be restarted four to six hours after sheath pull. Alternatively, some experts delay restarting these newer agents until the morning after the procedure. If the DOAC is restarted the morning after the procedure, we give either intravenous unfractionated heparin (no bolus; drip at 1000 to 1200 units per hour starting six hours after sheath pull and continued until the morning after the procedure) or low https://www.uptodate.com/contents/catheter-ablation-to-prevent-recurrent-atrial-fibrillation-anticoagulation/print 8/21 7/6/23, 2:49 PM Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation - UpToDate molecular weight heparin (enoxaparin 0.5 mg/kg; typically a single dose administered six hours after sheath pull). For patients previously not taking any oral agent, we suggest starting either a DOAC or warfarin. A first dose of either agent can be given six hours after an uncomplicated procedure. Patients started on warfarin will need to receive bridging treatment for a few days with low molecular weight heparin, as described directly above. LONG-TERM ANTICOAGULATION We continue oral therapy with the previously prescribed oral anticoagulant [44] for at least two months to ensure that the increased risk of embolization associated with the procedure, which lasts for about four weeks, has returned to a baseline risk and that there has been adequate time to document an absence of recurrence of atrial fibrillation (AF) for those patients in whom practitioners and patients are contemplating discontinuing anticoagulation [45]. (See 'Incidence, timing, and mechanism of embolism' above.) After this two-month period of mandatory oral anticoagulation, we generally restore the anticoagulant regimen in place prior to the procedure. For those patients without evidence of recurrent AF and whose risk for embolization is very low, such as those with a CHA DS -VASc 2 2 score of 0 ( table 1), we stop anticoagulation. (See "Atrial fibrillation in adults: Selection of candidates for anticoagulation", section on 'CHA2DS2-VASc score'.) Some experts are comfortable stopping anticoagulation in patients with a CHA DS -VASc score 2 2 of 1 ( table 1) after sufficient documentation of the absence of recurrent episodes of AF. We believe this approach has not been adequately tested. Therefore, we tell patients and referring physicians that the desire to stop long-term anticoagulation is not an indication for catheter ablation (CA) by itself. For all patients with a CHA DS -VASc score of >1 ( table 1) after CA, irrespective of whether or 2 2 not recurrence has been documented, we maintain the patient on long-term oral anticoagulation [46,47]. The optimal approach to chronic anticoagulation after successful CA, defined as no evidence of recurrence, is uncertain [48]. It is known that late recurrent AF occurs in 20 to 30 percent of patients, but the methods used in some studies likely underestimate the incidence [49-52]. (See "Atrial fibrillation: Catheter ablation", section on 'Efficacy'.) https://www.uptodate.com/contents/catheter-ablation-to-prevent-recurrent-atrial-fibrillation-anticoagulation/print 9/21 7/6/23, 2:49 PM Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation - UpToDate In a 2019 meta-analysis of five studies with nearly 4000 patients that evaluated safety and efficacy of long-term oral anticoagulation (OAC) compared with no OAC, the following was found during a mean follow-up of nearly 40 months [53]: In patients with a CHA DS -VASc score 2, OAC continuation was associated with a 2 2 decrease in the risk of thromboembolic events (risk ratio [RR] 0.41, 95% CI 0.21-0.82) but an increased risk of intracranial hemorrhage (ICH; RR 5.78, 95% CI 1.33-25.08). The absolute risk decrease in thromboembolic risk was 1.14 percent, while the increase in ICH was 0.7 percent. In patients with a CHA DS -VASc score of 0 or 1, the risk of ICH from OAC exceeded any 2 2 potential decrease in thromboembolic risk. The issue of the role of long-term anticoagulation was indirectly addressed by at least three studies that found a lower incidence of stroke comparing successful CA to antiarrhythmic drug therapy [54-56]. In a retrospective study of 174 matched pairs of AF individuals with a CHA2DS2- VASc score 1 who were treated with either antiarrhythmic drug therapy or CA and treated for at least three months with warfarin, the rate of stroke/transient ischemic attack was lower with the CA group (0.59 versus 2.21 percent per year) [54]. In those individuals treated with CA and in whom there was no AF recurrence, the stroke rate was very low compared to those with recurrence (0.8 versus 5.4 percent) after a mean follow-up period of 47 months. In addition, it is not known if asymptomatic recurrences result in a persistent thromboembolic risk in patients who have undergone CA. A low risk of stroke was reported in a series of 755 patients with longstanding persistent AF who underwent CA or a tailored approach [57]. In this cohort, anticoagulation was discontinued three months after the procedure in the majority of the 522 patients who did not have evidence of recurrent AF. During a median follow-up of 25 months, none of the patients who stopped anticoagulation had a stroke. Although these results are encouraging, the study cohort had a low baseline thromboembolic risk, with most having a CHADS2-VASc score of 0 to 2 ( table 1). Some of these patients, such as those with lone AF, would not require chronic oral anticoagulation whether or not they had a successful CA procedure. The following recommendations were made in the 2019 update of the 2014 American Heart Association/American College of Cardiology/Heart Rhythm Society AF guideline [58,59]: Systemic anticoagulation was recommended for at least two months in all patients following CA. https://www.uptodate.com/contents/catheter-ablation-to-prevent-recurrent-atrial-fibrillation-anticoagulation/print 10/21 7/6/23, 2:49 PM Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation - UpToDate After two months, the decision to continue anticoagulation should be based on the patient s risk factors for stroke and risk of bleeding, and not on the type of AF. The guideline acknowledges that recurrent episodes of AF, which may be asymptomatic, occur. The 2012 focused update of the European Society of Cardiology AF guideline recommends long- term oral anticoagulation CHA DS -VASc score of 2 [60]. The 2015 position document on 2 2 antithrombotic management in patients undergoing electrophysiological procedures states " the decision for oral anticoagulation depends on the patient s stroke risk profile and not the perceived success or failure of ablation " [43]. SOCIETY GUIDELINE LINKS Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Atrial fibrillation" and "Society guideline links: Arrhythmias in adults" and "Society guideline links: Catheter ablation of atrial fibrillation".) SUMMARY AND RECOMMENDATIONS The risk of stroke, transient ischemic attack, or other significant manifestation of embolization is increased, compared to baseline risk, at the time of catheter ablation (CA) for atrial fibrillation. (See 'Incidence, timing, and mechanism of embolism' above.) We perform a preprocedural transesophageal echocardiogram in most patients undergoing CA. The finding of intracardiac thrombus is a contraindication to the procedure. (See 'Role of transesophageal echocardiography' above.) Most patients scheduled to undergo CA who have been receiving long-term oral anticoagulation should continue to do so until the procedure. For those low-risk patients who have not been receiving long-term anticoagulation, including those in sinus rhythm at the time of the procedure, we suggest at least three weeks of effective anticoagulation prior to CA rather than no preprocedural anticoagulation (Grade 2C). An alternate approach is presented above. (See 'Preprocedural issues' above.) All patients should receive intraprocedural anticoagulation with intravenous heparin, irrespective of the patient s baseline thromboembolic risk and whether or not the procedure is performed on uninterrupted warfarin. (See 'Periprocedural issues' above.) https://www.uptodate.com/contents/catheter-ablation-to-prevent-recurrent-atrial-fibrillation-anticoagulation/print 11/21 7/6/23, 2:49 PM Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation - UpToDate For patients taking long-term oral anticoagulant with warfarin who present for CA, we recommend continuing such therapy rather than stopping and using a heparin bridge (Grade 1A). For patients taking long-term oral anticoagulant with a newer oral anticoagulant who present for CA, we suggest discontinuing such therapy before the procedure rather than continuing it (Grade 2B). (See 'Periprocedural issues' above.) For the uncommon patient who is at very high risk of a periprocedural stroke, it is reasonable to not discontinue direct oral anticoagulants (DOAC; also referred to as non- vitamin K oral anticoagulants [NOAC]). (See 'Patients taking DOACs' above.) DOAC may be restarted four to six hours after sheath pull. Alternatively, DOAC may be restarted the morning after the procedure in patients who are treated overnight with either intravenous unfractionated heparin (no bolus; drip at 1000 to 1200 units per hour starting six hours after sheath pull and continued until the morning after the procedure) or low molecular weight heparin (enoxaparin 0.5 mg/kg; typically a single dose at six hours after sheath pull). (See 'Patients taking DOACs' above.) Oral anticoagulation is continued for at least two months after the procedure in all patients. After two months, the decision to continue anticoagulation should be based on the patient s risk factors for stroke and risk of bleeding and not on the type of AF or outcome of the procedure. (See 'Long-term anticoagulation' above.) Use of UpToDate is subject to the Terms of Use. REFERENCES 1. Spragg DD, Dalal D, Cheema A, et al. Complications of catheter ablation for atrial fibrillation: incidence and predictors. J Cardiovasc Electrophysiol 2008; 19:627. 2. Cappato R, Calkins H, Chen SA, et al. Prevalence and causes of fatal outcome in catheter ablation of atrial fibrillation. J Am Coll Cardiol 2009; 53:1798. 3. Page SP, Herring N, Hunter RJ, et al. Periprocedural stroke risk in patients undergoing catheter ablation for atrial fibrillation on uninterrupted warfarin. J Cardiovasc Electrophysiol 2014; 25:585. 4. Kosiuk J, Kornej J, Bollmann A, et al. Early cerebral thromboembolic complications after radiofrequency catheter ablation of atrial fibrillation: incidence, characteristics, and risk factors. Heart Rhythm 2014; 11:1934. https://www.uptodate.com/contents/catheter-ablation-to-prevent-recurrent-atrial-fibrillation-anticoagulation/print 12/21 7/6/23, 2:49 PM Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation - UpToDate 5. Michaud GF. Silent cerebral embolism during catheter ablation of atrial fibrillation: how concerned should we be? Circulation 2010; 122:1662. 6. Gaita F, Caponi D, Pianelli M, et al. Radiofrequency catheter ablation of atrial fibrillation: a cause of silent thromboembolism? Magnetic resonance imaging assessment of cerebral thromboembolism in patients undergoing ablation of atrial fibrillation. Circulation 2010; 122:1667. 7. Schrickel JW, Lickfett L, Lewalter T, et al. Incidence and predictors of silent cerebral embolism during pulmonary vein catheter ablation for atrial fibrillation. Europace 2010; 12:52. 8. Herm J, Fiebach JB, Koch L, et al. Neuropsychological effects of MRI-detected brain lesions after left atrial catheter ablation for atrial fibrillation: long-term results of the MACPAF study. Circ Arrhythm Electrophysiol 2013; 6:843. 9. Verma A, Debruyne P, Nardi S, et al. Evaluation and reduction of asymptomatic cerebral embolism in ablation of atrial fibrillation, but high prevalence of chronic silent infarction: results of the evaluation of reduction of asymptomatic cerebral embolism trial. Circ Arrhythm Electrophysiol 2013; 6:835. 10. Ichiki H, Oketani N, Ishida S, et al. The incidence of asymptomatic cerebral microthromboembolism after atrial fibrillation ablation: comparison of warfarin and dabigatran. Pacing Clin Electrophysiol 2013; 36:1328. 11. Haines DE. ERACEing the risk of cerebral embolism from atrial fibrillation ablation. Circ Arrhythm Electrophysiol 2013; 6:827. 12. Medi C, Evered L, Silbert B, et al. Subtle post-procedural cognitive dysfunction after atrial fibrillation ablation. J Am Coll Cardiol 2013; 62:531. 13. Shah RR, Pillai A, Schafer P, et al. Safety and Efficacy of Uninterrupted Apixaban Therapy Versus Warfarin During Atrial Fibrillation Ablation. Am J Cardiol 2017; 120:404. 14. Kim JS, She F, Jongnarangsin K, et al. Dabigatran vs warfarin for radiofrequency catheter ablation of atrial fibrillation. Heart Rhythm 2013; 10:483. 15. Nin T, Sairaku A, Yoshida Y, et al. A randomized controlled trial of dabigatran versus warfarin for periablation anticoagulation in patients undergoing ablation of atrial fibrillation. Pacing Clin Electrophysiol 2013; 36:172. 16. Winkle RA, Mead RH, Engel G, et al. The use of dabigatran immediately after atrial fibrillation ablation. J Cardiovasc Electrophysiol 2012; 23:264. 17. Bassiouny M, Saliba W, Rickard J, et al. Use of dabigatran for periprocedural anticoagulation in patients undergoing catheter ablation for atrial fibrillation. Circ Arrhythm Electrophysiol https://www.uptodate.com/contents/catheter-ablation-to-prevent-recurrent-atrial-fibrillation-anticoagulation/print 13/21 7/6/23, 2:49 PM Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation - UpToDate 2013; 6:460. 18. Maddox W, Kay GN, Yamada T, et al. Dabigatran versus warfarin therapy for uninterrupted oral anticoagulation during atrial fibrillation ablation. J Cardiovasc Electrophysiol 2013; 24:861. 19. Lakkireddy D, Reddy YM, Di Biase L, et al. Feasibility and safety of uninterrupted rivaroxaban for periprocedural anticoagulation in patients undergoing radiofrequency ablation for atrial fibrillation: results from a multicenter prospective registry. J Am Coll Cardiol 2014; 63:982. 20. Dillier R, Ammar S, Hessling G, et al. Safety of continuous periprocedural rivaroxaban for patients undergoing left atrial catheter ablation procedures. Circ Arrhythm Electrophysiol 2014; 7:576. 21. Lakkireddy D, Reddy YM, Di Biase L, et al. Feasibility and safety of dabigatran versus warfarin for periprocedural anticoagulation in patients undergoing radiofrequency ablation for atrial fibrillation: results from a multicenter prospective registry. J Am Coll Cardiol 2012; 59:1168. 22. Provid ncia R, Albenque JP, Combes S, et al. Safety and efficacy of dabigatran versus warfarin in patients undergoing catheter ablation of atrial fibrillation: a systematic review and meta-analysis. Heart 2014; 100:324. 23. Bin Abdulhak AA, Khan AR, Tleyjeh IM, et al. Safety and efficacy of interrupted dabigatran for peri-procedural anticoagulation in catheter ablation of atrial fibrillation: a systematic review and meta-analysis. Europace 2013; 15:1412. 24. Hohnloser SH, Camm AJ. Safety and efficacy of dabigatran etexilate during catheter ablation of atrial fibrillation: a meta-analysis of the literature. Europace 2013; 15:1407. 25. Wu S, Yang YM, Zhu J, et al. Meta-Analysis of Efficacy and Safety of New Oral Anticoagulants Compared With Uninterrupted Vitamin K Antagonists in Patients Undergoing Catheter Ablation for Atrial Fibrillation. Am J Cardiol 2016; 117:926. 26. Knight BP. Transesophageal echocardiography before atrial fibrillation ablation: looking before cooking. J Am Coll Cardiol 2009; 54:2040. 27. Calkins H, Kuck KH, Cappato R, et al. 2012 HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: recommendations for patient selection, procedural techniques, patient management and follow-up, definitions, endpoints, and research trial design: a report of the Heart Rhythm Society (HRS) Task Force on Catheter and Surgical Ablation of Atrial Fibrillation. Developed in partnership with the European Heart Rhythm Association (EHRA), a registered branch of the European Society of Cardiology (ESC) and the European Cardiac Arrhythmia Society (ECAS); and in collaboration with the American College of Cardiology (ACC), American Heart Association (AHA), the Asia Pacific https://www.uptodate.com/contents/catheter-ablation-to-prevent-recurrent-atrial-fibrillation-anticoagulation/print 14/21 7/6/23, 2:49 PM Catheter ablation to prevent recurrent atrial fibrillation: Anticoagulation - UpToDate Heart Rhythm Society (APHRS), and the Society of Thoracic Surgeons (STS). Endorsed by the governing bodies of the American College of Cardiology Foundation, the American Heart Association, the European Cardiac Arrhythmia Society, the European Heart Rhythm Association, the Society of Thor 28. Rathi VK, Reddy ST, Anreddy S, et al. Contrast-enhanced CMR is equally effective as TEE in the evaluation of left atrial appendage thrombus in patients with atrial fibrillation undergoing pulmonary vein isolation procedure. Heart Rhythm 2013; 10:1021. 29. Chen J, Zhang H, Zhu D, et al. Cardiac MRI for detecting left atrial/left atrial appendage thrombus in patients with atrial fibrillation : Meta-analysis and systematic review. Herz 2019; 44:390. 30. Puwanant S, Varr BC, Shrestha K, et al. Role of the CHADS2 score in the evaluation of thromboembolic risk in patients with atrial fibrillation undergoing transesophageal echocardiography before pulmonary vein isolation. J Am Coll Cardiol 2009; 54:2032. 31. Saksena S, Sra J, Jordaens L, et al. A prospective comparison of cardiac imaging using intracardiac echocardiography with transesophageal echocardiography in patients with