No direct evidence of ICD failure for non-MRI conditional devices after scan
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An analysis of more 800 MRI examinations shows the scans do not induce clinically significant functional changes in non-MRI-conditional implantable cardioverter defibrillators, data from a single-center study show.
The findings build upon previous safety data at Johns Hopkins and other institutions showing no clinically significant changes in device parameters after MRI with non-MRI-conditional devices, according to Joshua Ra, MD, a physician with University of California, San Francisco.
“While many institutions have adopted MRI safety protocols for scanning patients with non-MRI-conditional ICDs, not all institutions offer these services and these patients continue to face significant barriers accessing clinically necessary MRI exams,” Ra told Healio. “The findings from this study provide further safety data to support institutions expanding access to MRI exams for this patient population.”
In a prospective study, Ra and colleagues analyzed data from 629 patients with non-MRI conditional ICDs who underwent 813 MRI exams at a magnetic field strength of 1.5 T. Researchers collected ICD data after each MRI and assessed outcomes including arrhythmia detection and treatment, generator or lead exchanges, adverse events and death.
The findings were published in Annals of Internal Medicine.
During a median follow-up of 2.2 years from MRI to latest available ICD interrogation before generator or lead exchange in 536 patients, researchers detected 4,177 arrhythmia episodes, and 97 patients received ICD shocks. Among these, 10% had 130 spontaneous ventricular tachycardia or fibrillation events terminated by ICD shocks. Within the cohort, 33% died a median of 1.7 years after MRI; three patients had cardiac arrhythmia deaths where shocks were indicated without direct evidence of device dysfunction.
“In our cohort of 629 patients with non–MRI-conditional ICD devices prospectively followed after MRI, we found no direct evidence of ICD failure to deliver therapy,” the researchers wrote. “In particular, shocks were delivered to and terminated more than 200 documented episodes of tachyarrhythmias in almost 100 patients.”
Ra said continued large-scale studies on the safety of MRI in patients with epicardial and abandoned leads, various ICD systems including subcutaneous ICDs, and direct comparisons between non-MRI-conditional and MRI-conditional ICDs may be of interest. “Safety with higher-strength MRI scanners and MRI acquisition techniques to minimize imaging artifacts from the presence of ICDs are also areas of ongoing research,” Ra told Healio.
For more information:
Joshua Ra, MD, can be reached at joshua.ra@ucsf.edu.
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