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Original Research |

A Prospective Evaluation of a Protocol for Magnetic Resonance Imaging of Patients With Implanted Cardiac Devices

Saman Nazarian, MD; Rozann Hansford, RN, MPH; Ariel Roguin, MD, PhD; Dorith Goldsher, MD; Menekhem M. Zviman, PhD; Albert C. Lardo, PhD; Brian S. Caffo, PhD; Kevin D. Frick, PhD, MA; Michael A. Kraut, MD, PhD; Ihab R. Kamel, MD, PhD; Hugh Calkins, MD; Ronald D. Berger, MD, PhD; David A. Bluemke, MD, PhD; and Henry R. Halperin, MD, MA
[+] Article and Author Information

From Johns Hopkins University, Baltimore, Maryland; Rambam Medical Center, Technion Institute of Technology, Haifa, Israel; and Radiology and Imaging Sciences, National Institutes of Biomedical Imaging and Bioengineering, Bethesda, Maryland.


Grant Support: By National Institutes of Health grants R01-HL64795 and R01-HL094610 to Dr. Halperin and K23-HL089333 to Dr. Nazarian, and a PJ Schafer Memorial Research Award.

Potential Conflicts of Interest: Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M10-2403.

Reproducible Research Statement:Study protocol and statistical code: Available from Dr. Nazarian (e-mail, snazarian@jhmi.edu). Data set: Certain portions of the analytic data set available to approved individuals through institutional review board approval and written agreements from Drs. Nazarian (e-mail, snazarian@jhmi.edu) and Halperin (e-mail, hhalper@jhmi.edu).

Requests for Single Reprints: Saman Nazarian, MD, Johns Hopkins Hospital, 600 North Wolfe Street, Carnegie 592C, Baltimore, MD 21287; e-mail, snazarian@jhmi.edu.

Current Author Addresses: Dr. Nazarian: Johns Hopkins Hospital, 600 North Wolfe Street, Carnegie 592C, Baltimore, MD 21287.

Ms. Hansford and Dr. Zviman: Johns Hopkins University, 702 Rutland Avenue, Traylor 903, Baltimore, MD 21287.

Dr. Roguin: Cardiology Department, Rambam Medical Center, B. Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 31096, Israel.

Dr. Goldsher: MRI Unit, Radiology Department, Rambam Medical Center, B. Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 31096, Israel.

Dr. Lardo: Johns Hopkins University, 1042 Ross Building, Baltimore, MD 21287.

Dr. Caffo: Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, E3610, Baltimore, MD 21205.

Dr. Frick: Johns Hopkins Bloomberg School of Public Health, 624 North Broadway, Room 606, Baltimore, MD 21205.

Dr. Kraut: Johns Hopkins Hospital, 600 North Wolfe Street, Houck B-112B, Baltimore MD 21287.

Dr. Kamel: MRI Unit, Department of Radiology, Johns Hopkins University, Baltimore, MD 21287.

Drs. Calkins and Berger: Johns Hopkins Outpatient Center, 601 North Caroline Street, Baltimore, MD 21287.

Dr. Bluemke: Department of Radiology, National Institutes of Biomedical Imaging and Bioengineering, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892.

Dr. Halperin: Johns Hopkins Hospital, 600 North Wolfe Street, Blalock 524A, Baltimore, MD 21287.

Author Contributions: Conception and design: S. Nazarian, A. Roguin, M.M. Zviman, A.C. Lardo, I.R. Kamel, H. Calkins, H.R. Halperin.

Analysis and interpretation of the data: S. Nazarian, R. Hansford, A. Roguin, D. Goldsher, B.S. Caffo, K.D. Frick, I.R. Kamel, D.A. Bluemke, H.R. Halperin.

Drafting of the article: S. Nazarian, A. Roguin, B.S. Caffo, I.R. Kamel.

Critical revision of the article for important intellectual content: S. Nazarian, A. Roguin, D. Goldsher, M.M. Zviman, A.C. Lardo, B.S. Caffo, I.R. Kamel, H. Calkins, R.D. Berger, D.A. Bluemke, H.R. Halperin.

Final approval of the article: S. Nazarian, A. Roguin, D. Goldsher, B.S. Caffo, K.D. Frick, M.A. Kraut, I.R. Kamel, H. Calkins, H.R. Halperin.

Provision of study materials or patients: A. Roguin, H. Calkins.

Statistical expertise: B.S. Caffo.

Obtaining of funding: S. Nazarian.

Administrative, technical, or logistic support: R. Hansford, D. Goldsher, M.M. Zviman, M.A. Kraut, I.R. Kamel, D.A. Bluemke.

Collection and assembly of data: S. Nazarian, R. Hansford, A. Roguin, D. Goldsher, I.R. Kamel, H. Calkins, D.A. Bluemke, H.R. Halperin.


Ann Intern Med. 2011;155(7):415-424. doi:10.7326/0003-4819-155-7-201110040-00004
Text Size: A A A

Background: Magnetic resonance imaging (MRI) is avoided in most patients with implanted cardiac devices because of safety concerns.

Objective: To define the safety of a protocol for MRI at the commonly used magnetic strength of 1.5 T in patients with implanted cardiac devices.

Design: Prospective nonrandomized trial. (ClinicalTrials.gov registration number: NCT01130896)

Setting: One center in the United States (94% of examinations) and one in Israel.

Patients: 438 patients with devices (54% with pacemakers and 46% with defibrillators) who underwent 555 MRI studies.

Intervention: Pacing mode was changed to asynchronous for pacemaker-dependent patients and to demand for others. Tachyarrhythmia functions were disabled. Blood pressure, electrocardiography, oximetry, and symptoms were monitored by a nurse with experience in cardiac life support and device programming who had immediate backup from an electrophysiologist.

Measurements: Activation or inhibition of pacing, symptoms, and device variables.

Results: In 3 patients (0.7% [95% CI, 0% to 1.5%]), the device reverted to a transient back-up programming mode without long-term effects. Right ventricular (RV) sensing (median change, 0 mV [interquartile range {IQR}, −0.7 to 0 V]) and atrial and right and left ventricular lead impedances (median change, −2 Ω [IQR, −13 to 0 Ω], −4 Ω [IQR, −16 to 0 Ω], and −11 Ω [IQR, −40 to 0 Ω], respectively) were reduced immediately after MRI. At long-term follow-up (61% of patients), decreased RV sensing (median, 0 mV, [IQR, −1.1 to 0.3 mV]), decreased RV lead impedance (median, −3 Ω, [IQR, −29 to 15 Ω]), increased RV capture threshold (median, 0 V, IQR, [0 to 0.2 Ω]), and decreased battery voltage (median, −0.01 V, IQR, −0.04 to 0 V) were noted. The observed changes did not require device revision or reprogramming.

Limitations: Not all available cardiac devices have been tested. Long-term in-person or telephone follow-up was unavailable in 43 patients (10%), and some data were missing. Those with missing long-term capture threshold data had higher baseline right atrial and right ventricular capture thresholds and were more likely to have undergone thoracic imaging. Defibrillation threshold testing and random assignment to a control group were not performed.

Conclusion: With appropriate precautions, MRI can be done safely in patients with selected cardiac devices. Because changes in device variables and programming may occur, electrophysiologic monitoring during MRI is essential.

Primary Funding Source: National Institutes of Health.

Figures

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Figure.
Safety protocol for MRI in the setting of implanted cardiac devices.

DDI = dual-chamber inhibited pacing without atrial tracking; DOO = dual-chamber asynchronous pacing; ECG = electrocardiography; ICD = implantable cardioverter-defibrillator; MRI = magnetic resonance imaging; PVC = premature ventricular contraction; VOO = ventricular asynchronous pacing; VVI = ventricular inhibited pacing.

* Adapted from reference (9).

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Summary for Patients

The Safety of Magnetic Resonance Imaging in Patients With Pacemakers or Defibrillators

The full report is titled “A Prospective Evaluation of a Protocol for Magnetic Resonance Imaging of Patients With Implanted Cardiac Devices.” It is in the 4 October 2011 issue of Annals of Internal Medicine (volume 155, pages 415-424). The authors are S. Nazarian, R. Hansford, A. Roguin, D. Goldsher, M.M. Zviman, A.C. Lardo, B.S. Caffo, K.D. Frick, M.A. Kraut, I.R. Kamel, H. Calkins, R.D. Berger, D.A. Bluemke, and H.R. Halperin.

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