International Journal of Cardiology 184 (2015) 497–498
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Letter to the Editor
Necessity of magnetic resonance imaging examinations after permanent pacemaker implantation Akira Taruya a, Atsushi Tanaka a,⁎, Tsuyoshi Nishiguchi a, Tetsuya Iwaguro b, Satoshi Ueno b, Yasushi Okumoto b, Takashi Kubo a, Hideharu Akagi b, Takashi Akasaka a a b
Department of Cardiovascular Medicine, Wakayama Medical University, Wakayama, Japan Department of Cardiovascular Medicine, Kinan Hospital, Tanabe, Japan
a r t i c l e
i n f o
Article history: Received 12 January 2015 Accepted 21 February 2015 Available online 25 February 2015 Keywords: Pacemaker Magnetic resonance imaging Prognosis Arrhythmia Cerebral ischemia
Magnetic resonance imaging (MRI) examinations as a powerful diagnostic tool have dramatically increased. More than 370,000 patients received implantable device-based therapy in the USA in 2003 [1]. However, patients receiving permanent pacemaker implantation (PMI) are contraindicated for MRI recommended by the U.S. Food and Drug Administration [1,2] and by device manufacturers [3–5]. There is an estimation that up to 75% of patients with pacemakers develop an indication for MRI over the lifetime of device owing to medical comorbidities [6,7] and an estimated 200,000 patients might have benefited from MRI. Even though some manufactures have developed several types of MRIconditional pacemakers, no actual data is available for the necessity of MRI after pacemaker implantation. The aim of this study was to investigate the prevalence and predictors of MRI-required events after PMI. PMI was performed in 254 patients at Kinan Hospital between January 2000 and September 2012. All patients received regular follow-up at the outpatient clinic of our hospital. After excluded one for moving and 3 for non-cardiac death, we were able to follow-up and analyze 250 (98.4%) patients. Patient's records were systematically reviewed by our hospital specialists (radiologist, neurologist, cardiologist, orthopedist, gynecologist, and urologist) who were blinded to the purpose of this study. The ⁎ Corresponding author at: Department of Cardiovascular Medicine, Wakayama Medical University, 811-1, Kimiidera, Wakayama, 641-8510, Japan. E-mail address: [email protected] (A. Tanaka).
http://dx.doi.org/10.1016/j.ijcard.2015.02.080 0167-5273/© 2015 Elsevier Ireland Ltd. All rights reserved.
event judged to need MRI by them was defined as a MRI-required event. The patients were divided into two groups (an event group and a non-event group) depending on the MRI-required events. Categorical variables were summarized as frequencies with percentages and compared by χ2 analysis. A multivariable logistic regression model was used to determine the risk factor of MRI-required events. Those variables that were kinds of arrhythmia and basal heart diseases were included in the multivariable logistic analysis. The cumulative event rate was estimated using the Kaplan–Meier method. All tests were 2-tailed, and statistical significance was defined as a P b 0.05. Of the 250 patients, 42 (16.8%) underwent MRI-required events during the mean observation period of 38.1 months. The baseline characteristics and transthoracic echocardiography data of the enrolled patients are summarized in Table 1. There were no differences in patient's characteristics between the two groups. No significant predictive factor was associated with the future MRI-required event in multivariable logistic analysis. The Kaplan–Meier analysis showed that the MRI-required event cumulatively increased at the rate of 5.3%/year after PMI (Fig. 1). Among the events, intracranial disease was found in 18 (43%), heart disease in 5 (12%), upper canal disease in 6 (14%), lower canal disease in 12 (29%), and pelvic area disease in 1 (2%). Alternative modalities were applied in 90.7% of them. Our hospital covers the entire Kinan area (1,403 km2), which is isolated from the near urban area. Its residents rarely move and spend all their life within this area. Furthermore, people must visit us when they fall into any kind of disease because only our hospital can provide full advanced medical services in this area. Therefore, we could conduct an almost complete follow-up survey (98.4%) even though this study was designed as a retrospective study. Due to the lack of a prospective study, we cannot compare our result with previous data. It's estimated that after PMI, up to 75% of patients with devices develop an indication for MRI owing to medical comorbidities within their lifetime [6,7]. Considering the relatively long life expectancy after PMI, our result seems to be comparable to the above estimation when patients could be alive more than 10 years after PMI. Another study reported that 17% of patients with pacemakers experienced difficulty when undergoing MRI [8]. This data is very similar to our result of 16.8%. The safety of MRI use in patients with conventional pacemakers has been debated for years. Levine et al. [7] and Irnich et al. [9] reported
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A. Taruya et al. / International Journal of Cardiology 184 (2015) 497–498
Table 1 Baseline clinical characteristics.
Age, y Male sex, n (%) SSS, n (%) AVblock, n (%) Af, n (%) Ischemic heart disease, n (%) Valve disease, n (%) Cardiomyopathy, n (%) Diabetes mellitus, n (%) Hypertension, n (%) Dyslipidemia, n (%) Smoking, n (%) Obesity (BMI ≧ 25 kg/m2), n (%) BMI, kg/m2 LA dimension, mm LVEF, % LVEDV, ml LVESV, ml
Event group (n = 42)
Non-event group (n = 208)
P value
73.7 ± 8.1 21(50) 21(50) 19(45) 15(36) 6(14) 6(14) 3(7) 8(19) 26(62) 11(26) 11(26) 10(24) 22.7 ± 2.4 45.1 ± 6.5 66.6 ± 10.1 106.3 ± 27.1 37.7 ± 18.0
76.5 ± 8.1 90(43) 91(44) 117(56) 46(22) 27(13) 17(8) 4(2) 26(13) 118(57) 40(19) 45(22) 54(26) 22.4 ± 2.8 43.3 ± 6.9 67.7 ± 9.9 113.9 ± 29.8 39.1 ± 19.2
0.07 0.41 0.44 0.18 0.06 0.83 0.22 0.10 0.26 0.52 0.28 0.53 0.83 0.44 0.24 0.82 0.55 0.78
SSS, sick sinus syndrome; AVB, atrioventricular block; AF, atrial fibrillation; BMI, body mass index; LA, left atrium; LVEF, left ventricular ejection fraction; LVEDV, left ventricular end-diastolic volume; LVESV, left ventricular end-systolic volume. Data presented are mean value ± SD, median [interquartile range], or numbers (%).
some fatalities. Sommer T et al. [10] have demonstrated specific effects during MRI of the heart, which could result in tissue damage. These studies suggested that using MRI with conventional pacemakers was controversial. Recently, some types of MRI-conditional pacemaker have been introduced into the clinical setting. There are several differences between the MRI-conditional and conventional pacemaker systems in terms of generator size, lead size, and type of lead. In addition, no long-term data is available for the MRI-conditional pacemaker. Therefore, there should be a discussion regarding the indication of the MRI-conditional pacemaker. The lack of actual data for MRI necessity disturbs the evidenced-based discussion. We believe that our data could be used for the discussion. In this study, we failed to find any specific factors that have an influence on MRI-required events and variety of areas that would be needed for MRI. On the other hand, the MRI-required events occur cumulatively at the rate of 5.3%/year. Our results suggest that MRI-conditional pacemaker would be better to be considered for all patients, especially with a long life expectancy. There are some limitations in this study. First, this is a retrospective study. Even though the follow-up rate was 98.4%, some events might be failed to count. The second is this is a single center study. Our area faces the critical problem of a super-aging society. Therefore, we should more carefully consider the result when applied to an urban community. The third is dependence on the specialists for definition of MRI-required events. Indication of MRI might leave considerable discretion to individual physicians and it would depend on individual health-care environments. Finally, we didn't investigate non-pacemaker patients.
Fig. 1. Cumulative MRI-required event rate. The Kaplan–Meier analysis shows that the MRI-required event cumulatively increases at the rate of 5.3% per year after permanent pacemaker implantation.
Conflict of interest The authors report no relationships that could be construed as a conflict of interest. References [1] O.P. Faris, M. Shein, Government viewpoint: U.S. Food & Drug Administration: pacemakers, ICDs and MRI, Pacing Clin. Electrophysiol. 28 (2005) 268–269. [2] O.P. Faris, M. Shein, Food and Drug Administration perspective: magnetic resonance imaging of pacemakers and implantable cardioverter-defibrillator patients, Circulation 114 (2006) 1232–1233. [3] J.M. Smith, Industry viewpoint: Guidant: pacemakers, ICDs, and MRI, Pacing Clin. Electrophysiol. 28 (2005) 264. [4] M.S. Stanton, Industry viewpoint: Medtronic: pacemakers, ICDs, and MRI, Pacing Clin. Electrophysiol. 28 (2005) 265. [5] P.A. Levine, Industry viewpoint: St. Jude Medical: pacemakers, ICDs, and MRI, Pacing Clin. Electrophysiol. 28 (2005) 266–267. [6] R. Kalin, M.S. Stanton, Current clinical issues for MRI scanning of pacemaker and defibrillator patients, Pacing Clin. Electrophysiol. 28 (2005) 326–328. [7] G.N. Levine, A.S. Gomes, A.E. Arai, D.A. Bluemke, S.D. Flamm, E. Kanal, et al., American Heart Association Committee on Diagnostic and Interventional Cardiac Catheterization. Safety of magnetic resonance imaging in patients with cardiovascular device: an American Heart Association scientific statement from the Committee on Diagnostic and Interventional Cardiac Catheterization, Council on Clinical Cardiology, and the Council on Cardiovascular Radiology and Intervention: endorsed by the American College of Cardiology Foundation, the North American Society for Cardiac Imaging, and the Society for Cardiovascular Magnetic Resonance, Circulation 116 (2007) 2878–2891. [8] Y. Sakakibara, T. Mitsui, Concerns about source of electromagnetic interference in patients with pacemakers, Jpn. Heart J. 40 (1999) 737–743. [9] W. Irnich, B. Irnich, C. Bartsch, W.A. Stertmann, H. Gufler, G. Weller, Do we need pacemakers resistant to magnetic resonance imaging? Europace 7 (2005) 353–365. [10] T. Sommer, C.P. Naehle, A. Yang, V. Zeijlemaker, M. Hackenbroch, A. Schmiedel, et al., Strategy for safe performance of extrathoracic MRI at 1.5 T in the presence of cardiac pacemakers in non-pacemaker dependent patients: a prospective study with 115 examinations, Circulation 114 (2006) 1285–1292.
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Letter to the Editor
Necessity of magnetic resonance imaging examinations after permanent pacemaker implantation Akira Taruya a, Atsushi Tanaka a,⁎, Tsuyoshi Nishiguchi a, Tetsuya Iwaguro b, Satoshi Ueno b, Yasushi Okumoto b, Takashi Kubo a, Hideharu Akagi b, Takashi Akasaka a a b
Department of Cardiovascular Medicine, Wakayama Medical University, Wakayama, Japan Department of Cardiovascular Medicine, Kinan Hospital, Tanabe, Japan
a r t i c l e
i n f o
Article history: Received 12 January 2015 Accepted 21 February 2015 Available online 25 February 2015 Keywords: Pacemaker Magnetic resonance imaging Prognosis Arrhythmia Cerebral ischemia
Magnetic resonance imaging (MRI) examinations as a powerful diagnostic tool have dramatically increased. More than 370,000 patients received implantable device-based therapy in the USA in 2003 [1]. However, patients receiving permanent pacemaker implantation (PMI) are contraindicated for MRI recommended by the U.S. Food and Drug Administration [1,2] and by device manufacturers [3–5]. There is an estimation that up to 75% of patients with pacemakers develop an indication for MRI over the lifetime of device owing to medical comorbidities [6,7] and an estimated 200,000 patients might have benefited from MRI. Even though some manufactures have developed several types of MRIconditional pacemakers, no actual data is available for the necessity of MRI after pacemaker implantation. The aim of this study was to investigate the prevalence and predictors of MRI-required events after PMI. PMI was performed in 254 patients at Kinan Hospital between January 2000 and September 2012. All patients received regular follow-up at the outpatient clinic of our hospital. After excluded one for moving and 3 for non-cardiac death, we were able to follow-up and analyze 250 (98.4%) patients. Patient's records were systematically reviewed by our hospital specialists (radiologist, neurologist, cardiologist, orthopedist, gynecologist, and urologist) who were blinded to the purpose of this study. The ⁎ Corresponding author at: Department of Cardiovascular Medicine, Wakayama Medical University, 811-1, Kimiidera, Wakayama, 641-8510, Japan. E-mail address: [email protected] (A. Tanaka).
http://dx.doi.org/10.1016/j.ijcard.2015.02.080 0167-5273/© 2015 Elsevier Ireland Ltd. All rights reserved.
event judged to need MRI by them was defined as a MRI-required event. The patients were divided into two groups (an event group and a non-event group) depending on the MRI-required events. Categorical variables were summarized as frequencies with percentages and compared by χ2 analysis. A multivariable logistic regression model was used to determine the risk factor of MRI-required events. Those variables that were kinds of arrhythmia and basal heart diseases were included in the multivariable logistic analysis. The cumulative event rate was estimated using the Kaplan–Meier method. All tests were 2-tailed, and statistical significance was defined as a P b 0.05. Of the 250 patients, 42 (16.8%) underwent MRI-required events during the mean observation period of 38.1 months. The baseline characteristics and transthoracic echocardiography data of the enrolled patients are summarized in Table 1. There were no differences in patient's characteristics between the two groups. No significant predictive factor was associated with the future MRI-required event in multivariable logistic analysis. The Kaplan–Meier analysis showed that the MRI-required event cumulatively increased at the rate of 5.3%/year after PMI (Fig. 1). Among the events, intracranial disease was found in 18 (43%), heart disease in 5 (12%), upper canal disease in 6 (14%), lower canal disease in 12 (29%), and pelvic area disease in 1 (2%). Alternative modalities were applied in 90.7% of them. Our hospital covers the entire Kinan area (1,403 km2), which is isolated from the near urban area. Its residents rarely move and spend all their life within this area. Furthermore, people must visit us when they fall into any kind of disease because only our hospital can provide full advanced medical services in this area. Therefore, we could conduct an almost complete follow-up survey (98.4%) even though this study was designed as a retrospective study. Due to the lack of a prospective study, we cannot compare our result with previous data. It's estimated that after PMI, up to 75% of patients with devices develop an indication for MRI owing to medical comorbidities within their lifetime [6,7]. Considering the relatively long life expectancy after PMI, our result seems to be comparable to the above estimation when patients could be alive more than 10 years after PMI. Another study reported that 17% of patients with pacemakers experienced difficulty when undergoing MRI [8]. This data is very similar to our result of 16.8%. The safety of MRI use in patients with conventional pacemakers has been debated for years. Levine et al. [7] and Irnich et al. [9] reported
498
A. Taruya et al. / International Journal of Cardiology 184 (2015) 497–498
Table 1 Baseline clinical characteristics.
Age, y Male sex, n (%) SSS, n (%) AVblock, n (%) Af, n (%) Ischemic heart disease, n (%) Valve disease, n (%) Cardiomyopathy, n (%) Diabetes mellitus, n (%) Hypertension, n (%) Dyslipidemia, n (%) Smoking, n (%) Obesity (BMI ≧ 25 kg/m2), n (%) BMI, kg/m2 LA dimension, mm LVEF, % LVEDV, ml LVESV, ml
Event group (n = 42)
Non-event group (n = 208)
P value
73.7 ± 8.1 21(50) 21(50) 19(45) 15(36) 6(14) 6(14) 3(7) 8(19) 26(62) 11(26) 11(26) 10(24) 22.7 ± 2.4 45.1 ± 6.5 66.6 ± 10.1 106.3 ± 27.1 37.7 ± 18.0
76.5 ± 8.1 90(43) 91(44) 117(56) 46(22) 27(13) 17(8) 4(2) 26(13) 118(57) 40(19) 45(22) 54(26) 22.4 ± 2.8 43.3 ± 6.9 67.7 ± 9.9 113.9 ± 29.8 39.1 ± 19.2
0.07 0.41 0.44 0.18 0.06 0.83 0.22 0.10 0.26 0.52 0.28 0.53 0.83 0.44 0.24 0.82 0.55 0.78
SSS, sick sinus syndrome; AVB, atrioventricular block; AF, atrial fibrillation; BMI, body mass index; LA, left atrium; LVEF, left ventricular ejection fraction; LVEDV, left ventricular end-diastolic volume; LVESV, left ventricular end-systolic volume. Data presented are mean value ± SD, median [interquartile range], or numbers (%).
some fatalities. Sommer T et al. [10] have demonstrated specific effects during MRI of the heart, which could result in tissue damage. These studies suggested that using MRI with conventional pacemakers was controversial. Recently, some types of MRI-conditional pacemaker have been introduced into the clinical setting. There are several differences between the MRI-conditional and conventional pacemaker systems in terms of generator size, lead size, and type of lead. In addition, no long-term data is available for the MRI-conditional pacemaker. Therefore, there should be a discussion regarding the indication of the MRI-conditional pacemaker. The lack of actual data for MRI necessity disturbs the evidenced-based discussion. We believe that our data could be used for the discussion. In this study, we failed to find any specific factors that have an influence on MRI-required events and variety of areas that would be needed for MRI. On the other hand, the MRI-required events occur cumulatively at the rate of 5.3%/year. Our results suggest that MRI-conditional pacemaker would be better to be considered for all patients, especially with a long life expectancy. There are some limitations in this study. First, this is a retrospective study. Even though the follow-up rate was 98.4%, some events might be failed to count. The second is this is a single center study. Our area faces the critical problem of a super-aging society. Therefore, we should more carefully consider the result when applied to an urban community. The third is dependence on the specialists for definition of MRI-required events. Indication of MRI might leave considerable discretion to individual physicians and it would depend on individual health-care environments. Finally, we didn't investigate non-pacemaker patients.
Fig. 1. Cumulative MRI-required event rate. The Kaplan–Meier analysis shows that the MRI-required event cumulatively increases at the rate of 5.3% per year after permanent pacemaker implantation.
Conflict of interest The authors report no relationships that could be construed as a conflict of interest. References [1] O.P. Faris, M. Shein, Government viewpoint: U.S. Food & Drug Administration: pacemakers, ICDs and MRI, Pacing Clin. Electrophysiol. 28 (2005) 268–269. [2] O.P. Faris, M. Shein, Food and Drug Administration perspective: magnetic resonance imaging of pacemakers and implantable cardioverter-defibrillator patients, Circulation 114 (2006) 1232–1233. [3] J.M. Smith, Industry viewpoint: Guidant: pacemakers, ICDs, and MRI, Pacing Clin. Electrophysiol. 28 (2005) 264. [4] M.S. Stanton, Industry viewpoint: Medtronic: pacemakers, ICDs, and MRI, Pacing Clin. Electrophysiol. 28 (2005) 265. [5] P.A. Levine, Industry viewpoint: St. Jude Medical: pacemakers, ICDs, and MRI, Pacing Clin. Electrophysiol. 28 (2005) 266–267. [6] R. Kalin, M.S. Stanton, Current clinical issues for MRI scanning of pacemaker and defibrillator patients, Pacing Clin. Electrophysiol. 28 (2005) 326–328. [7] G.N. Levine, A.S. Gomes, A.E. Arai, D.A. Bluemke, S.D. Flamm, E. Kanal, et al., American Heart Association Committee on Diagnostic and Interventional Cardiac Catheterization. Safety of magnetic resonance imaging in patients with cardiovascular device: an American Heart Association scientific statement from the Committee on Diagnostic and Interventional Cardiac Catheterization, Council on Clinical Cardiology, and the Council on Cardiovascular Radiology and Intervention: endorsed by the American College of Cardiology Foundation, the North American Society for Cardiac Imaging, and the Society for Cardiovascular Magnetic Resonance, Circulation 116 (2007) 2878–2891. [8] Y. Sakakibara, T. Mitsui, Concerns about source of electromagnetic interference in patients with pacemakers, Jpn. Heart J. 40 (1999) 737–743. [9] W. Irnich, B. Irnich, C. Bartsch, W.A. Stertmann, H. Gufler, G. Weller, Do we need pacemakers resistant to magnetic resonance imaging? Europace 7 (2005) 353–365. [10] T. Sommer, C.P. Naehle, A. Yang, V. Zeijlemaker, M. Hackenbroch, A. Schmiedel, et al., Strategy for safe performance of extrathoracic MRI at 1.5 T in the presence of cardiac pacemakers in non-pacemaker dependent patients: a prospective study with 115 examinations, Circulation 114 (2006) 1285–1292.
