International Journal of Cardiology 172 (2014) e529–e530
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Letter to the Editor
Clinical characteristics of atrial fibrillation detected by implanted devices and its association with ICD therapy Yoshiyasu Aizawa ⁎, Seiji Takatsuki, Masachika Negishi, Shin Kashimura, Yoshinori Katsumata, Takahiko Nishiyama, Takehiro Kimura, Nobuhiro Nishiyama, Yoko Tanimoto, Kojiro Tanimoto, Shun Kohsaka, Motoaki Sano, Keiichi Fukuda Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
a r t i c l e
i n f o
Article history: Received 30 November 2013 Accepted 18 January 2014 Available online 25 January 2014 Keywords: Pacemaker Implantable cardioverter-defibrillator Atrial fibrillation
Detection of atrial fibrillation (AF) by cardiac devices (CD) has high sensitivity and is useful in clinical situation. It was reported that subclinical atrial fibrillation detected by implanted devices were associated with an increased risk of ischemic stroke or systemic embolism [1,2]. ICD shocks are associated with adverse survival outcome. However the association between AF and ICD shocks was not fully understood. We studied 175 patients implanted with CD (32 pacemakers, 124 ICD, 19 CRT; Fig. 1) and managed by remote monitoring in our hospital. We evaluate clinical characteristics of AF detected by CD and occurrence of ICD therapy. The numerical values are presented as the means ± SDs. For comparisons, the differences between groups were analyzed by the Mann–Whitney–Wilcoxon test for continuous variables. Statistical analyses were performed with SPSS software (Statistical Package for the Social Sciences), version 12.0 (SPSS Inc., Chicago, IL). A two-sided P b 0.05 was considered statistically significant. The study was approved by the Institutional Review Committee of Keio University School of Medicine. The patients were given written informed consent prior to device implantation. During the mean follow-up period of 3.1 ± 1.7 years, AF was detected in 65 patients (37%) (Table 1). Mean CHADS2 score of
⁎ Corresponding author at: Department of Cardiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. Tel.: + 81 3 5363 3928; fax: +81 3 3353 1265. E-mail address: [email protected] (Y. Aizawa). 0167-5273/$ – see front matter © 2014 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ijcard.2014.01.067
these patients were 1.4 ± 1.1 (Fig. 2). In AF detected group ICD therapy was frequently observed but its difference was not statistically significant (25% vs. 13%, P = 0.070). Appropriate therapy was not different between with AF group and without AF group (3% vs. 5%). Inappropriate therapy was frequently observed in AF group (22% vs. 8%, P = 0.021). During the follow-up period, only 1 patient in AF group developed transient ischemic attack and oral anticoagulant was therefore initiated. The incidence of AF detection in patients with CD is 40–50% which is more sensitive compared to that by ECGs. Implantable monitoring devices can detect asymptomatic AF [2]. Although there are some differences between manufacturers, CD detects and records detailed atrial high rate episodes: time, frequency, cycle length and duration. Results from ASSERT study shows that in patients without history of AF, subclinical AF was detected 10.1% of patients by 3 months. Atrial high rate episodes N 190 bpm for more than 6 min were associated with an increased risk of ischemic stroke or systemic embolism. At least 1 atrial high rate episode of N220 bpm exceeding 5 min in patients with sinus node dysfunction doubles risk for death or stroke identify patients that are more than twice as likely to die or have a stroke, and 6 times higher to develop AF than patients without those episodes [1]. The false negative of AF detection by CD includes under sensing of atrial electrogram. The false positive of AF detection by CD includes P-wave double counting, far-field R wave oversensing and repetitive non-reentrant VA synchrony, myopotentials, lead failure and electromagnetical interference. In patients with an ICD, 20 to 25% of them receive inappropriate shocks [3]. The most frequent cause of inappropriate shocks is supraventricular tachyarrhythmia (SVT), such as sinus tachycardia, atrial fibrillation, and other paroxysmal supraventricular tachycardias. Rare causes include electromagnetical interference or lead malfunction. Not only inappropriate shocks decrease patients' QOL but also those are reported to be associated with a worse prognosis [4,5]. To decrease the inappropriate shocks by AF, rhythm control therapy by antiarrhythmic drugs or catheter ablation, or rate control therapy by drugs would be useful to manage these patients. In conclusion, during the mean follow-up period of 3.1 ± 1.7 years, AF was detected in 37% of the patients. These AF significantly increases inappropriate ICD therapy. We must manage to decrease ICD shocks in these patients.
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Y. Aizawa et al. / International Journal of Cardiology 172 (2014) e529–e530
A
B
C
Fig. 1. A: Proportion of each device in this study. B: Proportion of single chamber vs. single chamber devices in this study. C: Proportion of underlying disease in this study.
Table 1 Clinical characteristics of AF detected by devices and incidence of ICD shocks.
Male (%) Age CHADS2 score LAD (cm) LVEF (%) A pacing (%) V pacing (%) Overall shocks Appropriate shocks Inappropriate shocks
AF (+) (n = 65)
AF (−) (n = 110)
P value
47/65 (85) 67 ± 13 1.3 ± 1.1 4.1 ± 0.9 60 ± 18 17 ± 32 30 ± 40 16 (25) 2 (3) 14 (22)
81/110 (74) 61 ± 15 1.0 ± 1.2 3.9 ± 0.9 59 ± 19 24 ± 33 26 ± 41 14 (13) 5 (5) 9 (8)
1.000 0.079 0.520 0.489 0.524 0.698 0.963 0.070 0.920 0.021
References [1] 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. [2] Israel CW, Gronefeld G, Ehrlich JR, Li YG, Hohnloser SH. Long-term risk of recurrent atrial fibrillation as documented by an implantable monitoring device: implications for optimal patient care. J Am Coll Cardiol 2004;43:47–52. [3] Wood MA, Stambler BS, Damiano RJ, Greenway P, Ellenbogen KA. Lessons learned from data logging in a multicenter clinical trial using a late-generation implantable cardioverter-defibrillator. The Guardian ATP 4210 Multicenter Investigators Group. J Am Coll Cardiol 1994;24:1692–9. [4] Daubert JP, Zareba W, Cannom DS, et al. Inappropriate implantable cardioverterdefibrillator shocks in MADIT II: frequency, mechanisms, predictors, and survival impact. J Am Coll Cardiol 2008;51:1357–65.
Fig. 2. Distribution of CHADS2 score in AF detected patients.
[5] van Rees JB, Borleffs CJ, de Bie MK, et al. Inappropriate implantable cardioverterdefibrillator shocks: incidence, predictors, and impact on mortality. J Am Coll Cardiol 2011;57:556–62.
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Letter to the Editor
Clinical characteristics of atrial fibrillation detected by implanted devices and its association with ICD therapy Yoshiyasu Aizawa ⁎, Seiji Takatsuki, Masachika Negishi, Shin Kashimura, Yoshinori Katsumata, Takahiko Nishiyama, Takehiro Kimura, Nobuhiro Nishiyama, Yoko Tanimoto, Kojiro Tanimoto, Shun Kohsaka, Motoaki Sano, Keiichi Fukuda Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
a r t i c l e
i n f o
Article history: Received 30 November 2013 Accepted 18 January 2014 Available online 25 January 2014 Keywords: Pacemaker Implantable cardioverter-defibrillator Atrial fibrillation
Detection of atrial fibrillation (AF) by cardiac devices (CD) has high sensitivity and is useful in clinical situation. It was reported that subclinical atrial fibrillation detected by implanted devices were associated with an increased risk of ischemic stroke or systemic embolism [1,2]. ICD shocks are associated with adverse survival outcome. However the association between AF and ICD shocks was not fully understood. We studied 175 patients implanted with CD (32 pacemakers, 124 ICD, 19 CRT; Fig. 1) and managed by remote monitoring in our hospital. We evaluate clinical characteristics of AF detected by CD and occurrence of ICD therapy. The numerical values are presented as the means ± SDs. For comparisons, the differences between groups were analyzed by the Mann–Whitney–Wilcoxon test for continuous variables. Statistical analyses were performed with SPSS software (Statistical Package for the Social Sciences), version 12.0 (SPSS Inc., Chicago, IL). A two-sided P b 0.05 was considered statistically significant. The study was approved by the Institutional Review Committee of Keio University School of Medicine. The patients were given written informed consent prior to device implantation. During the mean follow-up period of 3.1 ± 1.7 years, AF was detected in 65 patients (37%) (Table 1). Mean CHADS2 score of
⁎ Corresponding author at: Department of Cardiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. Tel.: + 81 3 5363 3928; fax: +81 3 3353 1265. E-mail address: [email protected] (Y. Aizawa). 0167-5273/$ – see front matter © 2014 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ijcard.2014.01.067
these patients were 1.4 ± 1.1 (Fig. 2). In AF detected group ICD therapy was frequently observed but its difference was not statistically significant (25% vs. 13%, P = 0.070). Appropriate therapy was not different between with AF group and without AF group (3% vs. 5%). Inappropriate therapy was frequently observed in AF group (22% vs. 8%, P = 0.021). During the follow-up period, only 1 patient in AF group developed transient ischemic attack and oral anticoagulant was therefore initiated. The incidence of AF detection in patients with CD is 40–50% which is more sensitive compared to that by ECGs. Implantable monitoring devices can detect asymptomatic AF [2]. Although there are some differences between manufacturers, CD detects and records detailed atrial high rate episodes: time, frequency, cycle length and duration. Results from ASSERT study shows that in patients without history of AF, subclinical AF was detected 10.1% of patients by 3 months. Atrial high rate episodes N 190 bpm for more than 6 min were associated with an increased risk of ischemic stroke or systemic embolism. At least 1 atrial high rate episode of N220 bpm exceeding 5 min in patients with sinus node dysfunction doubles risk for death or stroke identify patients that are more than twice as likely to die or have a stroke, and 6 times higher to develop AF than patients without those episodes [1]. The false negative of AF detection by CD includes under sensing of atrial electrogram. The false positive of AF detection by CD includes P-wave double counting, far-field R wave oversensing and repetitive non-reentrant VA synchrony, myopotentials, lead failure and electromagnetical interference. In patients with an ICD, 20 to 25% of them receive inappropriate shocks [3]. The most frequent cause of inappropriate shocks is supraventricular tachyarrhythmia (SVT), such as sinus tachycardia, atrial fibrillation, and other paroxysmal supraventricular tachycardias. Rare causes include electromagnetical interference or lead malfunction. Not only inappropriate shocks decrease patients' QOL but also those are reported to be associated with a worse prognosis [4,5]. To decrease the inappropriate shocks by AF, rhythm control therapy by antiarrhythmic drugs or catheter ablation, or rate control therapy by drugs would be useful to manage these patients. In conclusion, during the mean follow-up period of 3.1 ± 1.7 years, AF was detected in 37% of the patients. These AF significantly increases inappropriate ICD therapy. We must manage to decrease ICD shocks in these patients.
e530
Y. Aizawa et al. / International Journal of Cardiology 172 (2014) e529–e530
A
B
C
Fig. 1. A: Proportion of each device in this study. B: Proportion of single chamber vs. single chamber devices in this study. C: Proportion of underlying disease in this study.
Table 1 Clinical characteristics of AF detected by devices and incidence of ICD shocks.
Male (%) Age CHADS2 score LAD (cm) LVEF (%) A pacing (%) V pacing (%) Overall shocks Appropriate shocks Inappropriate shocks
AF (+) (n = 65)
AF (−) (n = 110)
P value
47/65 (85) 67 ± 13 1.3 ± 1.1 4.1 ± 0.9 60 ± 18 17 ± 32 30 ± 40 16 (25) 2 (3) 14 (22)
81/110 (74) 61 ± 15 1.0 ± 1.2 3.9 ± 0.9 59 ± 19 24 ± 33 26 ± 41 14 (13) 5 (5) 9 (8)
1.000 0.079 0.520 0.489 0.524 0.698 0.963 0.070 0.920 0.021
References [1] 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. [2] Israel CW, Gronefeld G, Ehrlich JR, Li YG, Hohnloser SH. Long-term risk of recurrent atrial fibrillation as documented by an implantable monitoring device: implications for optimal patient care. J Am Coll Cardiol 2004;43:47–52. [3] Wood MA, Stambler BS, Damiano RJ, Greenway P, Ellenbogen KA. Lessons learned from data logging in a multicenter clinical trial using a late-generation implantable cardioverter-defibrillator. The Guardian ATP 4210 Multicenter Investigators Group. J Am Coll Cardiol 1994;24:1692–9. [4] Daubert JP, Zareba W, Cannom DS, et al. Inappropriate implantable cardioverterdefibrillator shocks in MADIT II: frequency, mechanisms, predictors, and survival impact. J Am Coll Cardiol 2008;51:1357–65.
Fig. 2. Distribution of CHADS2 score in AF detected patients.
[5] van Rees JB, Borleffs CJ, de Bie MK, et al. Inappropriate implantable cardioverterdefibrillator shocks: incidence, predictors, and impact on mortality. J Am Coll Cardiol 2011;57:556–62.
