Cardiac troponin T in patients with cardiac implantable electronic devices undergoing magnetic resonance imaging.

Purpose: Magnetic resonance imaging (MRI) has been safely performed in many patients with cardiac implantable electronic devices (CIEDs) using institution-specific protocols. A potential risk of MRI is myocardial heating and cardiac injury, which might be detectable with cardiac Troponin (cTn). We evaluated this in patients with CIEDs undergoing MRI.

Methods: Prospective data were collected from 2008 to the present in patients with CIEDs undergoing clinically indicated MRI performed under institutional protocol. Cardiac Troponin T (cTnT) levels were drawn both before and 24–36 h after the procedure. The collective data were retrospectively analyzed.

Results: MRI exams (n=512) were performed in 398 patients. Of these, there were 348 unique scans with cTnT recorded before and after MRI (median age 68, IQ 56–78; 62%men). cTnT did not significantly change for the group as a whole (0.00±0.056). There were 22 (6.3 %) exams with cTnT change ≥0.002 ng/mL following MRI (range 0.01–0.09 ng/mL). There were no clinically significant events in these patients directly attributable to MR. There were no significant changes in pacing threshold or impedance in the group with elevated cardiac biomarkers.

Conclusion: There are very few situations where myocardial injury as detected by cTnT in patients undergoing MRI with CIEDs could be detected. No adverse clinical events or functional changes of the device were noted, even in those with increases in cTnT. Our experience supports that MRI can be performed safely for appropriately selected patients under close clinical observation. Proactive monitoring with the present iteration of cardiac biomarkers appears to be of limited utility, but prospective monitoring with high sensitivity assays may be able to detect subclinical myocardial damage.