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MRI Safety |
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The quote "Don't take down a fence until you know the reason why it was put up" has been ascribed to several individuals and tribes likely because of the basic wisdom in the wit.
Medtronic does not recommend Medtronic implants be exposed to Magnetic Resonance Imagers because the device may be damaged or the patient injured. The manual for the Medtronic Concerto specifically calls this out on page 9. Enter 'Concerto' in the model # entry on the following website and check out the manual for the C154DWK which is the Concerto: |
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Medtronic Document Search |
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Now look at the manual for an older product like the EnRhythm P1501DR. The warning (again on page 9) is exactly the same. Without any further information, most individuals, including most physicians might think that Concerto is equally risky as Medtronic's older implants when exposed to high levels of radio energy such as generated by a Magnetic Resonance Imager. The problem is that some physicians have discovered that if they're careful they've been able to safely perform an MRI on older pacemakers and defibrillators without injuring the patient. In fact my alma mater, Johns Hopkins, published an article about how safe it is to expose cardiac implants to MRI's. |
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Johns Hopkins Article |
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The metal bodies of all cardiac implants have holes in them in order to provide electrical signals to the heart so as to provide therapy to the patient. For many years all cardiac implants have been made with radio filters placed in the holes whose function is to prevent high power radio waves from entering the implant and causing problems. Because the heart operates at a glacial pace compared to radio waves, these filters worked pretty well at rejecting radio energy. Likely this feature was added to cardiac implants many years ago in response to problems patients were experiencing caused by radio energy entering the implant.
In order to accomodate the new Conexus distance telemetry feature Medtronic had to add a hole to the metal body of their implant that does not include a filter. By not including a filter at a hole in the can, the implant manufacturers have enabled powerful new features, but they've also taken a step backwards in protection of the implants from external sources of radio energy. While I was employed by Medtronic, every Conexus radio engineer was concerned about exposure to high levels of radio energy, including MRI exposure.
Medtronic has indicated to physicians that their devices should not be used in MRI's, but Medtronic knows that some of their physicians expose implant patients to MRI anyway. In the interest of the safety of human life Medtronic should notify the public and physicians that Concerto is more susceptible to high power radio wave exposure as compared to previous generation devices. Medtronic is willfully endangering the safety of some patients by remaining silent about the new risks to the Concerto device from exposure to high-levels of radio energy. Medtronic at a minimum should at least inform physicians of the new risks.
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Recently, Medtronic announced a study of a new pacemaker system that is MRI safe. Here's the announcement: |
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Medtronic MRI Press Release |
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If Concerto is safe for high-level exposure to radio energy then why is Medtronic reverting to one of their "older" implants for the study? |
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