Letter to the Editor
Atrial fibrillation in cardiac implantable electronic devices and the duck test We read with great interest the article of Reiffel et al, 1 published in this issue of the Journal in January 2014, in which the authors describe the design of REVEAL AF addressing one of the main issues related to the incidence and clinical significance of “unrecognized” or “silent” atrial fibrillation (AF) detected by cardiac implantable electronic devices (CIED), in this case by the Reveal Insertable Cardiac Monitor (ICM) (Medtronic, Inc., Minneapolis, MN). Atrial high rate episodes (AHRE) N5 to 6 minutes detected by CIED have shown a high correlation with AF episodes confirmed by intracavitary electrograms. 2 These AHRE have been associated with an increased risk of ischemic stroke and systemic embolism in multiple studies. 3-5 Insertable Cardiac Monitor recordings offer a new perspective. Studies to determine the minimum duration of the episodes that increases risk for thromboembolic events have been requested by many authors; taking into account that duration can be also influenced by the individual CHADS2 score. Atrial fibrillation documented on electrocardiogram would lead to anticoagulation if appropriately attending to CHADS2 score, may be regardless of the duration of the episode. Patients with CIED may present asymptomatic AHRE documented on electrograms or ICM recordings compatible with AF. Why should we act different? “The duck test” says that if it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck. We have patients with CIED showing AHRE; these AHRE are compatible with AF and behave by increasing the stroke risk like AF… should not we treat them as AF or should we evaluate the duration of the episodes? Should we ask for the same studies about embolic risk for patients with paroxysmal AF attending to the duration of recurrences? Would it be possible by withdrawing anticoagulation in patients presenting short duration episodes? Would it be in the future that the ICM recordings compatible with AF considered like AHRE and so sharing limited implications regarding treatment of AF?
Lack of symptoms does not mean lack of risk. 6 Patients with CIED benefit from having a continuous monitorization system capable of unmasking silent AF episodes. “If it looks like AF, should we treat like AF?” Future guidelines should deal with this peculiar AF scenario to make professionals who routinely perform CIED follow-ups aware of these relevant episodes. Am Heart J 2014;167:e13. 0002-8703/$ - see front matter http://dx.doi.org/10.1016/j.ahj.2014.02.004
Juan Benezet-Mazuecos, MD Jose´ Manuel Rubio, MD, PhD Jero ´ nimo Farre´, MD, PhD Department of Cardiology Hospital Universitario Fundacio ´ n Jime´nez Dı´az–IDC Universidad Auto ´ noma de Madrid Madrid, Spain E-mail: [email protected]
References 1. Reiffel J, Verma A, Halperin JL, et al. Rationale and design of REVEAL AF: a prospective study of previously undiagnosed atrial fibrillation as documented by an insertable cardiac monitor in high-risk patients. Am Heart J 2014;167(1):22-7. 2. Pollack WM, Simmons JD, Interian A, et al. Clinical utility of intraatrial pacemaker stored electrograms to diagnose atrial fibrillation and flutter. PACE 2001;24:424-9. 3. Glotzer TV, Hellkamp AS, Zimmerman J, et al. Atrial high rate episodes detected by pacemaker diagnostics predict death and stroke: report of the Atrial Diagnostics Ancillary Study of the MOde Selection Trial (MOST). Circulation 2003;107:1614-9. 4. Healey JS, Connolly SJ, Gold MR, et al. Subclinical atrial fibrillation and the risk of stroke. N Engl J Med 2012;366:120-9. 5. Glotzer TV, Daoud EG, Wyse DG, et al. The relationship between daily atrial tachyarrhytmia burden from implantable device diagnostics and stroke risk: the TRENDS study. Circ Arrhythm Electrophysiol 2009;2: 474-80. 6. Savelieva I, Camm AJ. Clinical relevance of silent atrial fibrillation: prevalence, prognosis, quality of life, and management. J Interv Card Electrophysiol 2000;4:369-82.
Atrial fibrillation in cardiac implantable electronic devices and the duck test We read with great interest the article of Reiffel et al, 1 published in this issue of the Journal in January 2014, in which the authors describe the design of REVEAL AF addressing one of the main issues related to the incidence and clinical significance of “unrecognized” or “silent” atrial fibrillation (AF) detected by cardiac implantable electronic devices (CIED), in this case by the Reveal Insertable Cardiac Monitor (ICM) (Medtronic, Inc., Minneapolis, MN). Atrial high rate episodes (AHRE) N5 to 6 minutes detected by CIED have shown a high correlation with AF episodes confirmed by intracavitary electrograms. 2 These AHRE have been associated with an increased risk of ischemic stroke and systemic embolism in multiple studies. 3-5 Insertable Cardiac Monitor recordings offer a new perspective. Studies to determine the minimum duration of the episodes that increases risk for thromboembolic events have been requested by many authors; taking into account that duration can be also influenced by the individual CHADS2 score. Atrial fibrillation documented on electrocardiogram would lead to anticoagulation if appropriately attending to CHADS2 score, may be regardless of the duration of the episode. Patients with CIED may present asymptomatic AHRE documented on electrograms or ICM recordings compatible with AF. Why should we act different? “The duck test” says that if it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck. We have patients with CIED showing AHRE; these AHRE are compatible with AF and behave by increasing the stroke risk like AF… should not we treat them as AF or should we evaluate the duration of the episodes? Should we ask for the same studies about embolic risk for patients with paroxysmal AF attending to the duration of recurrences? Would it be possible by withdrawing anticoagulation in patients presenting short duration episodes? Would it be in the future that the ICM recordings compatible with AF considered like AHRE and so sharing limited implications regarding treatment of AF?
Lack of symptoms does not mean lack of risk. 6 Patients with CIED benefit from having a continuous monitorization system capable of unmasking silent AF episodes. “If it looks like AF, should we treat like AF?” Future guidelines should deal with this peculiar AF scenario to make professionals who routinely perform CIED follow-ups aware of these relevant episodes. Am Heart J 2014;167:e13. 0002-8703/$ - see front matter http://dx.doi.org/10.1016/j.ahj.2014.02.004
Juan Benezet-Mazuecos, MD Jose´ Manuel Rubio, MD, PhD Jero ´ nimo Farre´, MD, PhD Department of Cardiology Hospital Universitario Fundacio ´ n Jime´nez Dı´az–IDC Universidad Auto ´ noma de Madrid Madrid, Spain E-mail: [email protected]
References 1. Reiffel J, Verma A, Halperin JL, et al. Rationale and design of REVEAL AF: a prospective study of previously undiagnosed atrial fibrillation as documented by an insertable cardiac monitor in high-risk patients. Am Heart J 2014;167(1):22-7. 2. Pollack WM, Simmons JD, Interian A, et al. Clinical utility of intraatrial pacemaker stored electrograms to diagnose atrial fibrillation and flutter. PACE 2001;24:424-9. 3. Glotzer TV, Hellkamp AS, Zimmerman J, et al. Atrial high rate episodes detected by pacemaker diagnostics predict death and stroke: report of the Atrial Diagnostics Ancillary Study of the MOde Selection Trial (MOST). Circulation 2003;107:1614-9. 4. Healey JS, Connolly SJ, Gold MR, et al. Subclinical atrial fibrillation and the risk of stroke. N Engl J Med 2012;366:120-9. 5. Glotzer TV, Daoud EG, Wyse DG, et al. The relationship between daily atrial tachyarrhytmia burden from implantable device diagnostics and stroke risk: the TRENDS study. Circ Arrhythm Electrophysiol 2009;2: 474-80. 6. Savelieva I, Camm AJ. Clinical relevance of silent atrial fibrillation: prevalence, prognosis, quality of life, and management. J Interv Card Electrophysiol 2000;4:369-82.
