Anticoagulation after Catheter Ablation of Atrial Fibrillation Guided by Implantable Cardiac Monitors CHRISTINE S. ZUERN, M.D., ANTONIOS KILIAS, M.D., PATRICK BERLITZ, ¨ PETER SEIZER, M.D., MICHAEL GRAMLICH, M.D., KARIN MULLER, M.D., ¨ MARTIN DUCKHEIM, M.D., MEINRAD GAWAZ, M.D., and JURGEN SCHREIECK, M.D. From the Abteilung Innere Medizin III, Department of Cardiology, Eberhard-Karls-Universit¨at Tubingen, Tubingen, ¨ ¨ Germany
Background: Discontinuation of oral anticoagulation (OAC) after catheter ablation of atrial fibrillation (AF) is not recommended in patients with elevated CHADS2 scores. However, a low incidence of thromboembolic events is reported when OAC is stopped in these patients. We introduce an algorithm for discontinuation of OAC after ablation based on the AF burden documented by implantable cardiac monitors (ICM). Methods: Sixty-five patients with CHADS2 scores 1–3 free from AF 3 months after ablation (AF ablation [n = 49] or ablation of possible AF triggers [n = 16]) were included. One day after implantation of the ICM, OAC was stopped. Patients performed a daily interrogation of the ICM which was programmed to alarm the patient if daily AF burden exceeded 1 hour. Study end point was the first recurrence of a daily AF burden ࣙ1 hour or a thromboembolic event, which both triggered reinitiation of OAC. Results: During a follow-up time of 32 ± 12 months (126 patient-years), 41 of the 65 patients (63%) had an AF burden 30 seconds) or by ICM monitoring (Reveal XT, Medtronic Inc., Minneapolis, MN, USA, if already implanted before ablation; AF defined by atrial high-frequency episodes >2 minutes due to the software algorithm of the device) after a blanking period of 3 months after ablation, if they were classified as intermediate risk for thromboembolic events according to their CHADS2 score (scores 1–3), if they were highly motivated to stop OAC, and if they were judged to be able to understand and follow event-triggered reinitiation of anticoagulation. Exclusion criteria were CHADS2 score 0 or >3, valvular AF (defined as presence of mitral stenosis, mitral valve replacement, or surgical mitral valve reconstruction), longpersistent AF, history of intracardiac thrombi, or transitory ischemic attack (TIA)/stroke under anticoagulation or contraindication for OAC. The local ethics committee approved data collection and follow-up of the patients. Every patient gave written informed consent. Type of AF Ablation Forty-nine of the 65 patients underwent AF ablation. The remaining 16 patients, who also had documented paroxysmal AF, underwent possible trigger ablation of AF such as atrioventricular (AV) nodal reentrant tachycardia (n = 1), WolffParkinson-White (WPW) syndrome (n = 1), or ablation of typical atrial flutter (n = 14). All patients with AF ablation underwent pulmonary vein isolation (PVI). Hereof, six patients underwent PVI with cryoballoon. Twenty-two patients underwent circumferential PVI with 3D mappingguided radiofrequency ablation. Seventeen patients underwent PVI including robotic-navigated left atrial linear ablation. The remaining four patients underwent maze procedure including endoscopic thoracic box isolation of all pulmonary veins with radiofrequency, using the ablation system of AtriCure Inc., Cincinnati, OH, USA (without ligation of the left atrial appendage).
PACE, Vol. 38
ICM and Arrhythmia Recording ICM (Reveal XT, Medtronic Inc.) were implanted under local anesthesia in a left parasternal position where a sufficient R-wave detection was obtained without detection of myopotentials. Sensitivity was programmed to 0.05 mV. All devices were programmed to detect AF with the standard AF detection algorithm (“AF only”). Sinus rhythm and AF have unique patterns of R-R intervals. The AF detection algorithm of the Reveal XT ICM uses both irregularity and incoherence of the R-R intervals to analyze patterns in the ventricular conduction. By the algorithm, the R-R intervals are continuously assessed within a 2-minute time window. The difference between the duration of consecutive R-R intervals (delta R-R) is calculated. Then, similar to a Lorenz plot, the variability of this delta R-R is calculated. When the R-R intervals within a 2-minute time period show a pattern of uncorrelated irregularity, the episode is classified as AF. If the R-R intervals show regularity with sinus mode modulations, it is classified as sinus rhythm.10 Using this algorithm, oversensing of sinus tachycardia is reduced. The sensitivity of the algorithm to detect AF was previously assessed as 96.1% with a high negative predictive value of 97.4%.11 When AF is detected, it is recorded as AF episode within the automatic episode counter. When interrogated by the device programmer, date, time, and duration of the episode are displayed in detail. In total, the ICM can store up to 49.5 minutes of recorded ECG and can catalogue 30 automatically detected AF episodes. When the memory of the device is full, a new episode will overwrite the oldest one. All patients were handed out a hand-held tool (“Patient Assistant”) for performance of a daily self-interrogation of the device. The tool has a button which can be pressed by the patient to assess whether paroxysmal AF was recorded by the ICM. We programmed this tool to light up a warn signal if daily AF burden in total exceeded 60 minutes. The daily AF burden was counted every calendar day from 0:00 a.m. (midnight) to 11:59 p.m. If the patient did not interrogate the device on 1 day but only after 2 or more days, the warn signal would still light up if the AF burden had exceeded 1 hour on any of the prior days. One day after implantation, validation, and adjustment of the ICM, OAC was stopped. Follow-Up and Management of Event-Triggered Reinitiation of Anticoagulation Patients were instructed to perform a daily manual interrogation of their device. If the signal on the Patient Assistant lighted up, patients were
June 2015
689
ZUERN, ET AL.
Ablation of AF or possible AF triggers No evidence of AF after 3-month blanking period
optional
Postimplantation ICM adjustment of monitor ECG
Continued anticoagulation
AF confirmed
without myopotentials, sufficient QRS detection
Discontinutation of anticoagulation
Daily AF burden 10,000 patients of the SOS AF project.13 Third, types and strategies of management of AF were heterogeneous as approximately 25% of the patients underwent possible trigger ablation of AF such as AV nodal reentrant tachycardia, WPW syndrome, or ablation of typical atrial flutter. Finally, our study was observational and therefore has the characteristics shortcomings compared to a randomized trial. In conclusion, our study introduces a feasible clinical algorithm to discontinue OAC in patients with elevated CHADS2 scores after AF ablation of ablation of possible triggers of AF if they are continuously monitored by ICM and if the AF burden immediately triggers the reinitiation of anticoagulation.
June 2015
PACE, Vol. 38
ANTICOAGULATION AFTER AF ABLATION BY ICM
References 1. Oral H, Chugh A, Ozaydin M, Good E, Fortino J, Sankaran S, Reich S, et al. Risk of thromboembolic events after percutaneous left atrial radiofrequency ablation of atrial fibrillation. Circulation 2006; 114:759–765. 2. Nademanee K, Schwab MC, Kosar EM, Karwecki M, Moran MD, Visessook N, Michael AD, et al. Clinical outcomes of catheter substrate ablation for high-risk patients with atrial fibrillation. J Am Coll Cardiol 2008; 51:843–849. 3. Themistoclakis S, Corrado A, Marchlinski FE, Jais P, Zado E, Rossillo A, Di Biase L, et al. The risk of thromboembolism and need for oral anticoagulation after successful atrial fibrillation ablation. J Am Coll Cardiol 2010; 55:735–743. 4. Guiot A, Jongnarangsin K, Chugh A, Suwanagool A, Latchamsetty R, Myles JD, Jiang Q, et al. Anticoagulant therapy and risk of cerebrovascular events after catheter ablation of atrial fibrillation in the elderly. J Cardiovasc Electrophysiol 2012; 23:36–43. 5. Saad EB, d’Avila A, Costa IP, Aryana A, Slater C, Costa RE, Inacio LA Jr., et al. Very low risk of thromboembolic events in patients undergoing successful catheter ablation of atrial fibrillation with a CHADS2 score 10,000 patients from the SOS AF project (Stroke preventiOn Strategies based on Atrial Fibrillation information from implanted devices). Eur Heart J 2014; 35:508– 516. Daoud EG, Glotzer TV, Wyse DG, Ezekowitz MD, Hilker C, Koehler J, Ziegler PD, et al. Temporal relationship of atrial tachyarrhythmias, cerebrovascular events, and systemic emboli based on stored device data: A subgroup analysis of TRENDS. Heart Rhythm 2011; 8:1416– 1423. Brambatti M, Connolly SJ, Gold MR, Morillo CA, Capucci A, Muto C, Lau C, et al. Temporal relationship between subclinical atrial fibrillation and embolic events. Circulation 2014; 129:2094–2099. Ip J, Waldo AL, Lip GY, Rothwell PM, Martin DT, Bersohn MM, Choucair WK, et al. Multicenter randomized study of anticoagulation guided by remote rhythm monitoring in patients with implantable cardioverter defibrillator and CRT-D devices: Rationale, design, and clinical characteristics of the initially enrolled cohort. The IMPACT study. Am Heart J 2009; 158:364– 370, e361.
693
Background: Discontinuation of oral anticoagulation (OAC) after catheter ablation of atrial fibrillation (AF) is not recommended in patients with elevated CHADS2 scores. However, a low incidence of thromboembolic events is reported when OAC is stopped in these patients. We introduce an algorithm for discontinuation of OAC after ablation based on the AF burden documented by implantable cardiac monitors (ICM). Methods: Sixty-five patients with CHADS2 scores 1–3 free from AF 3 months after ablation (AF ablation [n = 49] or ablation of possible AF triggers [n = 16]) were included. One day after implantation of the ICM, OAC was stopped. Patients performed a daily interrogation of the ICM which was programmed to alarm the patient if daily AF burden exceeded 1 hour. Study end point was the first recurrence of a daily AF burden ࣙ1 hour or a thromboembolic event, which both triggered reinitiation of OAC. Results: During a follow-up time of 32 ± 12 months (126 patient-years), 41 of the 65 patients (63%) had an AF burden 30 seconds) or by ICM monitoring (Reveal XT, Medtronic Inc., Minneapolis, MN, USA, if already implanted before ablation; AF defined by atrial high-frequency episodes >2 minutes due to the software algorithm of the device) after a blanking period of 3 months after ablation, if they were classified as intermediate risk for thromboembolic events according to their CHADS2 score (scores 1–3), if they were highly motivated to stop OAC, and if they were judged to be able to understand and follow event-triggered reinitiation of anticoagulation. Exclusion criteria were CHADS2 score 0 or >3, valvular AF (defined as presence of mitral stenosis, mitral valve replacement, or surgical mitral valve reconstruction), longpersistent AF, history of intracardiac thrombi, or transitory ischemic attack (TIA)/stroke under anticoagulation or contraindication for OAC. The local ethics committee approved data collection and follow-up of the patients. Every patient gave written informed consent. Type of AF Ablation Forty-nine of the 65 patients underwent AF ablation. The remaining 16 patients, who also had documented paroxysmal AF, underwent possible trigger ablation of AF such as atrioventricular (AV) nodal reentrant tachycardia (n = 1), WolffParkinson-White (WPW) syndrome (n = 1), or ablation of typical atrial flutter (n = 14). All patients with AF ablation underwent pulmonary vein isolation (PVI). Hereof, six patients underwent PVI with cryoballoon. Twenty-two patients underwent circumferential PVI with 3D mappingguided radiofrequency ablation. Seventeen patients underwent PVI including robotic-navigated left atrial linear ablation. The remaining four patients underwent maze procedure including endoscopic thoracic box isolation of all pulmonary veins with radiofrequency, using the ablation system of AtriCure Inc., Cincinnati, OH, USA (without ligation of the left atrial appendage).
PACE, Vol. 38
ICM and Arrhythmia Recording ICM (Reveal XT, Medtronic Inc.) were implanted under local anesthesia in a left parasternal position where a sufficient R-wave detection was obtained without detection of myopotentials. Sensitivity was programmed to 0.05 mV. All devices were programmed to detect AF with the standard AF detection algorithm (“AF only”). Sinus rhythm and AF have unique patterns of R-R intervals. The AF detection algorithm of the Reveal XT ICM uses both irregularity and incoherence of the R-R intervals to analyze patterns in the ventricular conduction. By the algorithm, the R-R intervals are continuously assessed within a 2-minute time window. The difference between the duration of consecutive R-R intervals (delta R-R) is calculated. Then, similar to a Lorenz plot, the variability of this delta R-R is calculated. When the R-R intervals within a 2-minute time period show a pattern of uncorrelated irregularity, the episode is classified as AF. If the R-R intervals show regularity with sinus mode modulations, it is classified as sinus rhythm.10 Using this algorithm, oversensing of sinus tachycardia is reduced. The sensitivity of the algorithm to detect AF was previously assessed as 96.1% with a high negative predictive value of 97.4%.11 When AF is detected, it is recorded as AF episode within the automatic episode counter. When interrogated by the device programmer, date, time, and duration of the episode are displayed in detail. In total, the ICM can store up to 49.5 minutes of recorded ECG and can catalogue 30 automatically detected AF episodes. When the memory of the device is full, a new episode will overwrite the oldest one. All patients were handed out a hand-held tool (“Patient Assistant”) for performance of a daily self-interrogation of the device. The tool has a button which can be pressed by the patient to assess whether paroxysmal AF was recorded by the ICM. We programmed this tool to light up a warn signal if daily AF burden in total exceeded 60 minutes. The daily AF burden was counted every calendar day from 0:00 a.m. (midnight) to 11:59 p.m. If the patient did not interrogate the device on 1 day but only after 2 or more days, the warn signal would still light up if the AF burden had exceeded 1 hour on any of the prior days. One day after implantation, validation, and adjustment of the ICM, OAC was stopped. Follow-Up and Management of Event-Triggered Reinitiation of Anticoagulation Patients were instructed to perform a daily manual interrogation of their device. If the signal on the Patient Assistant lighted up, patients were
June 2015
689
ZUERN, ET AL.
Ablation of AF or possible AF triggers No evidence of AF after 3-month blanking period
optional
Postimplantation ICM adjustment of monitor ECG
Continued anticoagulation
AF confirmed
without myopotentials, sufficient QRS detection
Discontinutation of anticoagulation
Daily AF burden 10,000 patients of the SOS AF project.13 Third, types and strategies of management of AF were heterogeneous as approximately 25% of the patients underwent possible trigger ablation of AF such as AV nodal reentrant tachycardia, WPW syndrome, or ablation of typical atrial flutter. Finally, our study was observational and therefore has the characteristics shortcomings compared to a randomized trial. In conclusion, our study introduces a feasible clinical algorithm to discontinue OAC in patients with elevated CHADS2 scores after AF ablation of ablation of possible triggers of AF if they are continuously monitored by ICM and if the AF burden immediately triggers the reinitiation of anticoagulation.
June 2015
PACE, Vol. 38
ANTICOAGULATION AFTER AF ABLATION BY ICM
References 1. Oral H, Chugh A, Ozaydin M, Good E, Fortino J, Sankaran S, Reich S, et al. Risk of thromboembolic events after percutaneous left atrial radiofrequency ablation of atrial fibrillation. Circulation 2006; 114:759–765. 2. Nademanee K, Schwab MC, Kosar EM, Karwecki M, Moran MD, Visessook N, Michael AD, et al. Clinical outcomes of catheter substrate ablation for high-risk patients with atrial fibrillation. J Am Coll Cardiol 2008; 51:843–849. 3. Themistoclakis S, Corrado A, Marchlinski FE, Jais P, Zado E, Rossillo A, Di Biase L, et al. The risk of thromboembolism and need for oral anticoagulation after successful atrial fibrillation ablation. J Am Coll Cardiol 2010; 55:735–743. 4. Guiot A, Jongnarangsin K, Chugh A, Suwanagool A, Latchamsetty R, Myles JD, Jiang Q, et al. Anticoagulant therapy and risk of cerebrovascular events after catheter ablation of atrial fibrillation in the elderly. J Cardiovasc Electrophysiol 2012; 23:36–43. 5. Saad EB, d’Avila A, Costa IP, Aryana A, Slater C, Costa RE, Inacio LA Jr., et al. Very low risk of thromboembolic events in patients undergoing successful catheter ablation of atrial fibrillation with a CHADS2 score 10,000 patients from the SOS AF project (Stroke preventiOn Strategies based on Atrial Fibrillation information from implanted devices). Eur Heart J 2014; 35:508– 516. Daoud EG, Glotzer TV, Wyse DG, Ezekowitz MD, Hilker C, Koehler J, Ziegler PD, et al. Temporal relationship of atrial tachyarrhythmias, cerebrovascular events, and systemic emboli based on stored device data: A subgroup analysis of TRENDS. Heart Rhythm 2011; 8:1416– 1423. Brambatti M, Connolly SJ, Gold MR, Morillo CA, Capucci A, Muto C, Lau C, et al. Temporal relationship between subclinical atrial fibrillation and embolic events. Circulation 2014; 129:2094–2099. Ip J, Waldo AL, Lip GY, Rothwell PM, Martin DT, Bersohn MM, Choucair WK, et al. Multicenter randomized study of anticoagulation guided by remote rhythm monitoring in patients with implantable cardioverter defibrillator and CRT-D devices: Rationale, design, and clinical characteristics of the initially enrolled cohort. The IMPACT study. Am Heart J 2009; 158:364– 370, e361.
693
