I think that this study is methodologically-weak. An analogy would be if I blindfolded myself, walked back and forth across an interstate highway 10 times without injury, and published a paper stating that blindfolded-highway crossing was proven safe.
What about lead-tip heating? If it created scarring at the lead tip, many pacers would automatically increase the voltage needed to stimulate the cardiac muscle. Perhaps, as a consequence, a 5-year battery life gets shortened to 3-years, but that's an adverse event that wouldn't be uncovered by anything less than inspection and testing of the lead-implantation site.
I'm not suggesting that the conclusions of the study are incorrect, but rather that the methodology doesn't support the conclusions they put forward. What constitutes a 'modern' pacing device? What are the lead lengths, materials, and configurations? What about static field strength, gradient fields, RF frequencies and deposition? What about the clinical parameters for the patients? Are we talking about capture and correction pacer patients, or complete device dependence patients?
This study may have anecdotal value, but as with similar studies, the leaped-to 'sound bite' conclusion that MR imaging of patients with pacing devices is safe does a disservice to clinicians and patients alike. Yes, it may well be possible to image a particular patient, with a particular pacing device, on a particular scanner, set to specific sequences, with appropriate special provisions in place, but that is a far cry from the freedom of most MR imaging.
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I think that this study is methodologically-weak. An analogy would be if I blindfolded myself, walked back and forth across an interstate highway 10 times without injury, and published a paper stating that blindfolded-highway crossing was proven safe.
What about lead-tip heating? If it created scarring at the lead tip, many pacers would automatically increase the voltage needed to stimulate the cardiac muscle. Perhaps, as a consequence, a 5-year battery life gets shortened to 3-years, but that's an adverse event that wouldn't be uncovered by anything less than inspection and testing of the lead-implantation site.
I'm not suggesting that the conclusions of the study are incorrect, but rather that the methodology doesn't support the conclusions they put forward. What constitutes a 'modern' pacing device? What are the lead lengths, materials, and configurations? What about static field strength, gradient fields, RF frequencies and deposition? What about the clinical parameters for the patients? Are we talking about capture and correction pacer patients, or complete device dependence patients?
This study may have anecdotal value, but as with similar studies, the leaped-to 'sound bite' conclusion that MR imaging of patients with pacing devices is safe does a disservice to clinicians and patients alike. Yes, it may well be possible to image a particular patient, with a particular pacing device, on a particular scanner, set to specific sequences, with appropriate special provisions in place, but that is a far cry from the freedom of most MR imaging.
August 3, 2011 - 10:22amThis Comment
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