Is magnetic resonance imaging safe in cardiac pacemaker recipients?

ACCF/ACR/AHA/NASCI/SCMR 2010 Expert Consensus Document on Cardiovascular Magnetic Resonance

“…Another study suggested that ICDs and pacemakers manufactured after the year 2000 are more resistant to the electrical and magnetic fields associated with MR examination at 1.5-T 412. To date, it is likely that several hundred patients have undergone MR examination with either pacemakers or ICDs,413–419 and strategies and protocols for safe pacemaker/ICD scanning during CMR have been proposed 420,421. As of this writing, no deaths have been reported under conditions in which patients were deliberately scanned and monitored during the MR examination, although changes in pacing threshold, programming changes, need for device reprogramming, and possibly battery depletion have been reported.…”

Role of MRI in Patient Selection for CRT

“…However, a growing body of evidence suggests that patients with implanted devices can safely undergo MRI examinations if they are properly screened and carefully monitored 29,74,76–78 . However, it is important to note that current recommendations from both the device industry and the Food and Drug Administration reiterate that MRI imaging of patients with implanted devices should only be done on a case‐by‐case basis and when no alternative imaging modality exists 76,79–83 .…”

The AHA Scientific Statement of MRI in Patients with Devices: Neat, but Incomplete. Unwise and Unsupported

“…The document states “A physician with pacemaker ICD experience should decide whether it is necessary to reprogram the pacemaker before the MR examination … ” 1 Opinions differ with regard to the optimal programming strategy for device patients and several strategies have been used safely 3,5–7 . Excluding review articles, virtually all manuscripts published in this area 3–5,7 (with the notable exception of Martin et al 6 ) suggest that in nonpacemaker‐dependent patients, the patient's system should undergo extensive reprogramming prior to MRI with particular attention to the behavior of the device in response to magnet exposure. Several manufacturers (for instance Boston Scientific and St. Jude Medical) provide for programmability of the magnet response and this feature should be programmed “off” to avoid unpredictable asynchronous pacing.…”

“…That is to say “no strategy” or the “strategy of inadvertent scanning.” Combined, of course, with the patient's unmonitored status while in the MRI, the failure to reprogram the patient's pacemaker likely played a significant role in the death of the patient through the induction of a fatal arrhythmia 9 . Unless the reed switch function or magnet response can be programmed “off,” 5 the behavior of the magnet application may be unpredictable 10 with competitive pacing the result. In the absence of any reprogramming prior to MRI (which the AHA document suggests may be satisfactory), the patient may experience unwanted asynchronous pacing, which despite claims to the contrary, is not always benign and the arrhythmias could be catastrophic 11,12–14 .…”

“…Given that thousands of patients with devices might undergo MRI 3 and that many of these scans will last for prolonged periods (potentially resulting in prolonged asynchronous pacing if not programmed otherwise), why should we not reprogram each system prior to MRI in a manner that seeks to avoid the potentially lethal consequences of asynchronous pacing? The author and others 3–5,7,8 believe extensive reprogramming is wise prior to MRI, especially in nonpacemaker‐dependent patients. Attention to programming elements other than only the pacing mode is also important as has been noted elsewhere 5,15 …”