International Journal of Cardiology 178 (2015) 99–101
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Letter to the Editor
Risk factors for early replacement of cardiovascular implantable electronic devices Yoshiyasu Aizawa ⁎, Akira Kunitomi, Kazuaki Nakajima, Shin Kashimura, Yoshinori Katsumata, Takahiko Nishiyama, Takehiro Kimura, Nobuhiro Nishiyama, Yoko Tanimoto, Shun Kohsaka, Seiji Takatsuki, 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 28 September 2014 Received in revised form 23 October 2014 Accepted 24 October 2014 Available online 25 October 2014
on all patients using the electronic medical records or clinical charts. Detailed device information was collected from printouts obtained during routine follow-up. The primary endpoint was the device replacement for any reason. A univariate analysis was performed and all variables with a P value b 0.2 were included in the multivariate analysis with a Coxregression analysis. A P value of b0.05 was considered statistically significant. Patients were given written informed consent prior to the invasive procedures.
3. Results Keywords: Pacemaker Implantable cardioverter–defibrillator Cardiac resynchronization therapy Device replacement
1. Introduction Cardiovascular implantable electronic devices (CIEDs) improved the survival and quality-of-life in patients with various heart rhythm disorders [1]. However patients will need frequent device replacements during their remaining life span [2]. Battery depletion is the most common cause of device replacements. Device replacements increase the healthcare cost and risk of infection or hemorrhagic complications [3–5]. The estimated battery longevities provided by manufactures are based on calculated stable ideal conditions and they might differ in clinical practice. We assessed the hypothesis that there may exist some risk factors of shortening the replacement cycle that have not been fully clarified. The purpose of this study was to disclose the clinical factors for predicting frequent generator replacements. 2. Methods All 257 consecutive CIED replacements (228 patients) at the Keio University hospital from 2002 to 2013 were included in this retrospective study. The replaced devices were 96 pacemakers, 142 ICDs, 3 cardiac resynchronization therapy pacemakers (CRT-Ps) and 16 CRT defibrillators (CRT-Ds). The baseline demographic and clinical data were collected
⁎ Corresponding author at: Department of Cardiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. E-mail address: [email protected] (Y. Aizawa).
http://dx.doi.org/10.1016/j.ijcard.2014.10.157 0167-5273/© 2014 Elsevier Ireland Ltd. All rights reserved.
The baseline clinical characteristics of the patients included in this study are shown in Table 1. The mean age was 65 ± 15 years and 70% of the patients were men. Only one-fifth of the patients had coronary artery disease and a good left ventricular ejection fraction (62 ± 19%). The types of devices (single chamber or dual chamber), pacing percentage, pacing threshold, and lead impedance are summarized in Table 1. The proportion of each device and the device manufactures are shown in Fig. 1. The mean duration from the device implantation to the replacement was 6.0 ± 2.3 years (pacemaker 7.4 ± 2.3 years, CRT-P 6.4 ± 1.3 years, ICD 5.2 ± 1.7 years, and CRT-D 3.7 ± 1.2 years) (Fig. 2). The details of the replacement cycle per manufacturer for each device are shown in Fig. 2, but were not statistically significant. The reasons for generator replacements were: battery depletion (229 cases, 89%), and non-battery depletion (28 cases, 11%), which included lead failures (15 cases), upgrades (8 cases), device infections (4 cases) and T-wave oversensing (1 case). A multivariate Cox regression analysis demonstrated that there was an increased risk for an early replacement in patients with devices equipped with a defibrillator (hazard ratio [HR] 13.9; 95% CI 5.13–37.4, P b 0.001), increased V pacing of 10% (HR 1.08; 95% CI 1.01–1.15, P = 0.028), and non-battery depletion (HR 28.0; 95% CI 2.73–287, P = 0.005) (Table 2). There was no significant difference in the battery longevity between each manufacture. 4. Discussion Device replacements are invasive procedures and have the risk of infections, bleeding, hematomas, and mechanical damage to the implanted leads [3]. However all patients implanted with CIEDs may be required to have replacements for various reasons as long as the patient survives. In our cohort, approximately 90% of device replacements were due to battery depletion. Pacemakers and CRT-Ps had a longer battery longevity than ICDs or CRT-Ds. Especially with CRT-D devices, the replacement cycles were remarkably shortened as compared to that for
100
Y. Aizawa et al. / International Journal of Cardiology 178 (2015) 99–101
Table 1 Clinical characteristics of the patients included in this study. Variable
Overall (n = 257)
Pacemaker (n = 96)
ICD/CRT (n = 142/19)
Age, y Male, n (%) HTN, n (%) DM, n (%) CAD, n (%) AF, n (%) LVEF,% Single chamber, n (%) Dual chamber, n (%) A pacing, % V pacing, % A pacing threshold, V A pacing threshold, ms RV pacing threshold, V RV pacing threshold, ms LV pacing threshold, V LV pacing threshold, ms A lead impedance, ohm RV lead impedance, ohm LV lead impedance, ohm Rate response, n (%) Manufacturer, n (%) Medtronic St. Jude Medical Boston Scientific Biotronik Etc.
65 ± 15 179 (70) 61 (24) 29 (11) 47 (18) 62 (24) 62 ± 19 79 (31) 178 (69) 22 ± 35 30 ± 39 1.4 ± 1.1 0.3 ± 0.2 1.5 ± 0.8 0.3 ± 0.1 2.1 ± 1.7 0.5 ± 0.4 603 ± 240 586 ± 280 756 ± 308 22 (9)
74 ± 15 45 (47) 26 (27) 12 (13) 5 (5) 30 (31) 71 ± 15 23 (24) 73 (76) 36 ± 34 63 ± 41 0.8 ± 0.7 0.4 ± 0.01 1.1 ± 0.8 0.4 ± 0.1 – – 678 ± 280 694 ± 311 – 14 (15)
61 ± 13 134 (83) 35 (22) 17 (11) 42 (26) 32 (20) 56 ± 19 56 (35) 105 (65)⁎ 23 ± 36 26 ± 41 1.8 ± 1.2 0.3 ± 0.3 1.7 ± 0.6 0.3 ± 0.2 2.1 ± 1.7 0.5 ± 0.4 551 ± 194 522 ± 230 756 ± 308 8 (5)
166 (65) 45 (18) 32 (12) 11 (4) 3 (1)
38 (40) 22 (23) 26 (27) 8 (8) 2 (2)
128 (79) 23 (14) 6 (4) 3 (2) 1 (1)
⁎ All CRT devices were counted as dual chamber. HTN: hypertension, DM: diabetes mellitus, CAD: coronary artery disease, AF: atrial fibrillation, LVEF: left ventricular ejection fraction, A: atrial, V: ventricular, RV: right ventricular.
that the Medtronic CRT-Ds have a shorter battery longevity than the other manufactures [7]. We observed a similar tendency in our CRT-D cohort that Medtronic devices had a shorter survival than the Boston Scientific devices, but it was not statistically significant, possibly due to the small number of patients. In this study, we did not collect any data on automatic threshold measurements, which are proven to increase the device longevity [8]. We also could not detect any significant influence of rate response on the replacement cycle. This may be due to the limitation that the patient background in our study was heterogeneous and the number of patients was too small to analyze such parameters. Although modern devices have demonstrated an improved longevity [9], more improvement would be required for the patients' benefit. 5. Conclusions Although the majority of device replacements were because of battery depletion, about 10% of the devices were replaced for other reasons. Device replacements due to non-battery depletion including lead failures, and device infections are a risk for early replacements. Early replacements are required in the presence of complications such as lead failures or device infections. There are also significant discrepancies in the device replacement cycle between pacemakers and ICDs/CRTs. An increased replacement cycle will result in an improved cost-effectiveness of CIEDs and a reduction in the procedure related complications. Acknowledgment We are grateful to Mr. John Martin for his linguistic assistance. References
the other devices. This may be due to the need for nearly 100% biventricular pacing in CRT-D devices. The device longevity is known to differ according to the manufacturer [6], and Alam et al. reported
[1] A.E. Epstein, J.P. DiMarco, K.A. Ellenbogen, N.A. Estes III, R.A. Freedman, L.S. Gettes, et al., ACC/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: a report of the American College of Cardiology/American Heart
Fig. 1. A: Proportion of each device in this study. B: Proportion of the device manufactures of the ICD/CRT devices. C: Proportion of the device manufactures of the pacemaker devices.
Y. Aizawa et al. / International Journal of Cardiology 178 (2015) 99–101
101
Fig. 2. Device replacement cycle for each device.
Association Task Force on Practice Guidelines (writing committee to revise the ACC/ AHA/NASPE 2002 guideline update for implantation of cardiac pacemakers and antiarrhythmia devices): developed in collaboration with the American Association for Thoracic Surgery and Society of Thoracic Surgeons, Circulation 117 (2008) e350–e408. [2] R.G. Hauser, The growing mismatch between patient longevity and the service life of implantable cardioverter–defibrillators, J. Am. Coll. Cardiol. 45 (2005) 2022–2025. [3] C.J. Borleffs, J. Thijssen, M.K. de Bie, J.B. van Rees, G.H. van Welsenes, L. van Erven, et al., Recurrent implantable cardioverter–defibrillator replacement is associated with an increasing risk of pocket-related complications, Pacing Clin. Electrophysiol. 33 (2010) 1013–1019. [4] M.R. Reynolds, D.J. Cohen, A.D. Kugelmass, P.P. Brown, E.R. Becker, S.D. Culler, et al., The frequency and incremental cost of major complications among medicare beneficiaries receiving implantable cardioverter–defibrillators, J. Am. Coll. Cardiol. 47 (2006) 2493–2497.
Table 2 Cox proportional hazard regression model to predict device replacements. Univariate
Age Sex male HTN DM CAD Atrial fibrillation LVEF (10% increase) ICD/CRT-D Shock A pacing % (10% increase) V pacing % (10% increase) A pacing threshold V pacing threshold Rate response Medtronic Boston Scientific St. Jude Medical Biotronik Non battery depletion
Multivariate
HR
95% CI
P
HR
95% CI
P
0.99 1.64 0.90 0.83 1.35 0.70 0.83 3.67 3.06 0.96 0.97 1.27 1.16 0.75 1.42 1.16 0.45 1.01 2.81
0.98–0.99 1.24–2.17 0.68–1.21 0.55–1.23 0.98–1.88 0.52–0.94 0.77–0.90 2.74–4.92 2.13–4.40 0.90–1.01 0.93–1.00 1.11–1.45 1.01–1.33 0.48–1.17 1.09–1.86 0.83–1.61 0.28–0.73 0.55–1.86 1.83–4.31
b0.001 b0.001 0.49 0.35 0.07 0.018 b0.001 b0.001 b0.001 0.18 0.08 0.001 0.037 0.20 0.008 0.40 0.001 0.96 b0.001
1.00 1.14 – – 0.48 0.55 0.99 13.9 0.47 1.09 1.08 1.49 1.19 – 0.54 – 1.56 – 28.0
0.98–1.03 0.55–2.36 – – 0.18–1.27 0.22–1.34 0.84–1.17 5.13–37.4 1.22–1.80 1.00–1.20 1.01–1.15 0.91–2.43 0.83–1.72 – 0.24–1.22 – 1.65–5.91 – 2.73–287
0.80 0.73 – – 0.14 0.21 0.94 b0.001 0.27 0.053 0.028 0.11 0.35 – 0.14 – 0.45 – 0.005
[5] G.D. Sanders, M.A. Hlatky, D.K. Owens, Cost-effectiveness of implantable cardioverter–defibrillators, N. Engl. J. Med. 353 (2005) 1471–1480. [6] K.C. Siontis, I. Pantos, D.G. Katritsis, Comparison of the longevity of implantable cardioverter–defibrillator devices by different manufacturers, Int. J. Cardiol. 175 (2014) 380–382. [7] M.B. Alam, M.B. Munir, R. Rattan, S. Flanigan, E. Adelstein, S. Jain, et al., Battery longevity in cardiac resynchronization therapy implantable cardioverter defibrillators, Europace 16 (2014) 246–251. [8] L.S. Rosenthal, S. Mester, P. Rakovec, J.B. Penaranda, J.R. Sherman, T.J. Sheldon, et al., Factors influencing pacemaker generator longevity: results from the complete automatic pacing threshold utilization recorded in the CAPTURE Trial, Pacing Clin. Electrophysiol. 33 (2010) 1020–1030. [9] J. Thijssen, C.J. Borleffs, J.B. van Rees, S. Man, M.K. de Bie, J. Venlet, et al., Implantable cardioverter–defibrillator longevity under clinical circumstances: an analysis according to device type, generation, and manufacturer, Heart Rhythm. 9 (2012) 513–519.
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Letter to the Editor
Risk factors for early replacement of cardiovascular implantable electronic devices Yoshiyasu Aizawa ⁎, Akira Kunitomi, Kazuaki Nakajima, Shin Kashimura, Yoshinori Katsumata, Takahiko Nishiyama, Takehiro Kimura, Nobuhiro Nishiyama, Yoko Tanimoto, Shun Kohsaka, Seiji Takatsuki, 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 28 September 2014 Received in revised form 23 October 2014 Accepted 24 October 2014 Available online 25 October 2014
on all patients using the electronic medical records or clinical charts. Detailed device information was collected from printouts obtained during routine follow-up. The primary endpoint was the device replacement for any reason. A univariate analysis was performed and all variables with a P value b 0.2 were included in the multivariate analysis with a Coxregression analysis. A P value of b0.05 was considered statistically significant. Patients were given written informed consent prior to the invasive procedures.
3. Results Keywords: Pacemaker Implantable cardioverter–defibrillator Cardiac resynchronization therapy Device replacement
1. Introduction Cardiovascular implantable electronic devices (CIEDs) improved the survival and quality-of-life in patients with various heart rhythm disorders [1]. However patients will need frequent device replacements during their remaining life span [2]. Battery depletion is the most common cause of device replacements. Device replacements increase the healthcare cost and risk of infection or hemorrhagic complications [3–5]. The estimated battery longevities provided by manufactures are based on calculated stable ideal conditions and they might differ in clinical practice. We assessed the hypothesis that there may exist some risk factors of shortening the replacement cycle that have not been fully clarified. The purpose of this study was to disclose the clinical factors for predicting frequent generator replacements. 2. Methods All 257 consecutive CIED replacements (228 patients) at the Keio University hospital from 2002 to 2013 were included in this retrospective study. The replaced devices were 96 pacemakers, 142 ICDs, 3 cardiac resynchronization therapy pacemakers (CRT-Ps) and 16 CRT defibrillators (CRT-Ds). The baseline demographic and clinical data were collected
⁎ Corresponding author at: Department of Cardiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. E-mail address: [email protected] (Y. Aizawa).
http://dx.doi.org/10.1016/j.ijcard.2014.10.157 0167-5273/© 2014 Elsevier Ireland Ltd. All rights reserved.
The baseline clinical characteristics of the patients included in this study are shown in Table 1. The mean age was 65 ± 15 years and 70% of the patients were men. Only one-fifth of the patients had coronary artery disease and a good left ventricular ejection fraction (62 ± 19%). The types of devices (single chamber or dual chamber), pacing percentage, pacing threshold, and lead impedance are summarized in Table 1. The proportion of each device and the device manufactures are shown in Fig. 1. The mean duration from the device implantation to the replacement was 6.0 ± 2.3 years (pacemaker 7.4 ± 2.3 years, CRT-P 6.4 ± 1.3 years, ICD 5.2 ± 1.7 years, and CRT-D 3.7 ± 1.2 years) (Fig. 2). The details of the replacement cycle per manufacturer for each device are shown in Fig. 2, but were not statistically significant. The reasons for generator replacements were: battery depletion (229 cases, 89%), and non-battery depletion (28 cases, 11%), which included lead failures (15 cases), upgrades (8 cases), device infections (4 cases) and T-wave oversensing (1 case). A multivariate Cox regression analysis demonstrated that there was an increased risk for an early replacement in patients with devices equipped with a defibrillator (hazard ratio [HR] 13.9; 95% CI 5.13–37.4, P b 0.001), increased V pacing of 10% (HR 1.08; 95% CI 1.01–1.15, P = 0.028), and non-battery depletion (HR 28.0; 95% CI 2.73–287, P = 0.005) (Table 2). There was no significant difference in the battery longevity between each manufacture. 4. Discussion Device replacements are invasive procedures and have the risk of infections, bleeding, hematomas, and mechanical damage to the implanted leads [3]. However all patients implanted with CIEDs may be required to have replacements for various reasons as long as the patient survives. In our cohort, approximately 90% of device replacements were due to battery depletion. Pacemakers and CRT-Ps had a longer battery longevity than ICDs or CRT-Ds. Especially with CRT-D devices, the replacement cycles were remarkably shortened as compared to that for
100
Y. Aizawa et al. / International Journal of Cardiology 178 (2015) 99–101
Table 1 Clinical characteristics of the patients included in this study. Variable
Overall (n = 257)
Pacemaker (n = 96)
ICD/CRT (n = 142/19)
Age, y Male, n (%) HTN, n (%) DM, n (%) CAD, n (%) AF, n (%) LVEF,% Single chamber, n (%) Dual chamber, n (%) A pacing, % V pacing, % A pacing threshold, V A pacing threshold, ms RV pacing threshold, V RV pacing threshold, ms LV pacing threshold, V LV pacing threshold, ms A lead impedance, ohm RV lead impedance, ohm LV lead impedance, ohm Rate response, n (%) Manufacturer, n (%) Medtronic St. Jude Medical Boston Scientific Biotronik Etc.
65 ± 15 179 (70) 61 (24) 29 (11) 47 (18) 62 (24) 62 ± 19 79 (31) 178 (69) 22 ± 35 30 ± 39 1.4 ± 1.1 0.3 ± 0.2 1.5 ± 0.8 0.3 ± 0.1 2.1 ± 1.7 0.5 ± 0.4 603 ± 240 586 ± 280 756 ± 308 22 (9)
74 ± 15 45 (47) 26 (27) 12 (13) 5 (5) 30 (31) 71 ± 15 23 (24) 73 (76) 36 ± 34 63 ± 41 0.8 ± 0.7 0.4 ± 0.01 1.1 ± 0.8 0.4 ± 0.1 – – 678 ± 280 694 ± 311 – 14 (15)
61 ± 13 134 (83) 35 (22) 17 (11) 42 (26) 32 (20) 56 ± 19 56 (35) 105 (65)⁎ 23 ± 36 26 ± 41 1.8 ± 1.2 0.3 ± 0.3 1.7 ± 0.6 0.3 ± 0.2 2.1 ± 1.7 0.5 ± 0.4 551 ± 194 522 ± 230 756 ± 308 8 (5)
166 (65) 45 (18) 32 (12) 11 (4) 3 (1)
38 (40) 22 (23) 26 (27) 8 (8) 2 (2)
128 (79) 23 (14) 6 (4) 3 (2) 1 (1)
⁎ All CRT devices were counted as dual chamber. HTN: hypertension, DM: diabetes mellitus, CAD: coronary artery disease, AF: atrial fibrillation, LVEF: left ventricular ejection fraction, A: atrial, V: ventricular, RV: right ventricular.
that the Medtronic CRT-Ds have a shorter battery longevity than the other manufactures [7]. We observed a similar tendency in our CRT-D cohort that Medtronic devices had a shorter survival than the Boston Scientific devices, but it was not statistically significant, possibly due to the small number of patients. In this study, we did not collect any data on automatic threshold measurements, which are proven to increase the device longevity [8]. We also could not detect any significant influence of rate response on the replacement cycle. This may be due to the limitation that the patient background in our study was heterogeneous and the number of patients was too small to analyze such parameters. Although modern devices have demonstrated an improved longevity [9], more improvement would be required for the patients' benefit. 5. Conclusions Although the majority of device replacements were because of battery depletion, about 10% of the devices were replaced for other reasons. Device replacements due to non-battery depletion including lead failures, and device infections are a risk for early replacements. Early replacements are required in the presence of complications such as lead failures or device infections. There are also significant discrepancies in the device replacement cycle between pacemakers and ICDs/CRTs. An increased replacement cycle will result in an improved cost-effectiveness of CIEDs and a reduction in the procedure related complications. Acknowledgment We are grateful to Mr. John Martin for his linguistic assistance. References
the other devices. This may be due to the need for nearly 100% biventricular pacing in CRT-D devices. The device longevity is known to differ according to the manufacturer [6], and Alam et al. reported
[1] A.E. Epstein, J.P. DiMarco, K.A. Ellenbogen, N.A. Estes III, R.A. Freedman, L.S. Gettes, et al., ACC/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: a report of the American College of Cardiology/American Heart
Fig. 1. A: Proportion of each device in this study. B: Proportion of the device manufactures of the ICD/CRT devices. C: Proportion of the device manufactures of the pacemaker devices.
Y. Aizawa et al. / International Journal of Cardiology 178 (2015) 99–101
101
Fig. 2. Device replacement cycle for each device.
Association Task Force on Practice Guidelines (writing committee to revise the ACC/ AHA/NASPE 2002 guideline update for implantation of cardiac pacemakers and antiarrhythmia devices): developed in collaboration with the American Association for Thoracic Surgery and Society of Thoracic Surgeons, Circulation 117 (2008) e350–e408. [2] R.G. Hauser, The growing mismatch between patient longevity and the service life of implantable cardioverter–defibrillators, J. Am. Coll. Cardiol. 45 (2005) 2022–2025. [3] C.J. Borleffs, J. Thijssen, M.K. de Bie, J.B. van Rees, G.H. van Welsenes, L. van Erven, et al., Recurrent implantable cardioverter–defibrillator replacement is associated with an increasing risk of pocket-related complications, Pacing Clin. Electrophysiol. 33 (2010) 1013–1019. [4] M.R. Reynolds, D.J. Cohen, A.D. Kugelmass, P.P. Brown, E.R. Becker, S.D. Culler, et al., The frequency and incremental cost of major complications among medicare beneficiaries receiving implantable cardioverter–defibrillators, J. Am. Coll. Cardiol. 47 (2006) 2493–2497.
Table 2 Cox proportional hazard regression model to predict device replacements. Univariate
Age Sex male HTN DM CAD Atrial fibrillation LVEF (10% increase) ICD/CRT-D Shock A pacing % (10% increase) V pacing % (10% increase) A pacing threshold V pacing threshold Rate response Medtronic Boston Scientific St. Jude Medical Biotronik Non battery depletion
Multivariate
HR
95% CI
P
HR
95% CI
P
0.99 1.64 0.90 0.83 1.35 0.70 0.83 3.67 3.06 0.96 0.97 1.27 1.16 0.75 1.42 1.16 0.45 1.01 2.81
0.98–0.99 1.24–2.17 0.68–1.21 0.55–1.23 0.98–1.88 0.52–0.94 0.77–0.90 2.74–4.92 2.13–4.40 0.90–1.01 0.93–1.00 1.11–1.45 1.01–1.33 0.48–1.17 1.09–1.86 0.83–1.61 0.28–0.73 0.55–1.86 1.83–4.31
b0.001 b0.001 0.49 0.35 0.07 0.018 b0.001 b0.001 b0.001 0.18 0.08 0.001 0.037 0.20 0.008 0.40 0.001 0.96 b0.001
1.00 1.14 – – 0.48 0.55 0.99 13.9 0.47 1.09 1.08 1.49 1.19 – 0.54 – 1.56 – 28.0
0.98–1.03 0.55–2.36 – – 0.18–1.27 0.22–1.34 0.84–1.17 5.13–37.4 1.22–1.80 1.00–1.20 1.01–1.15 0.91–2.43 0.83–1.72 – 0.24–1.22 – 1.65–5.91 – 2.73–287
0.80 0.73 – – 0.14 0.21 0.94 b0.001 0.27 0.053 0.028 0.11 0.35 – 0.14 – 0.45 – 0.005
[5] G.D. Sanders, M.A. Hlatky, D.K. Owens, Cost-effectiveness of implantable cardioverter–defibrillators, N. Engl. J. Med. 353 (2005) 1471–1480. [6] K.C. Siontis, I. Pantos, D.G. Katritsis, Comparison of the longevity of implantable cardioverter–defibrillator devices by different manufacturers, Int. J. Cardiol. 175 (2014) 380–382. [7] M.B. Alam, M.B. Munir, R. Rattan, S. Flanigan, E. Adelstein, S. Jain, et al., Battery longevity in cardiac resynchronization therapy implantable cardioverter defibrillators, Europace 16 (2014) 246–251. [8] L.S. Rosenthal, S. Mester, P. Rakovec, J.B. Penaranda, J.R. Sherman, T.J. Sheldon, et al., Factors influencing pacemaker generator longevity: results from the complete automatic pacing threshold utilization recorded in the CAPTURE Trial, Pacing Clin. Electrophysiol. 33 (2010) 1020–1030. [9] J. Thijssen, C.J. Borleffs, J.B. van Rees, S. Man, M.K. de Bie, J. Venlet, et al., Implantable cardioverter–defibrillator longevity under clinical circumstances: an analysis according to device type, generation, and manufacturer, Heart Rhythm. 9 (2012) 513–519.
