Safety of magnetic resonance imaging in patients with legacy pacemakers and defibrillators and abandoned leads.

BACKGROUND: During magnetic resonance imaging (MRI), abandoned leads may act as antennae that result in tissue heating and arrhythmia induction.

OBJECTIVE: The purpose of this study was to assess the safety of MRI in patients with abandoned leads, with the addition of cardiac troponin T (cTnT) assessment to screen for myocardial damage.

METHODS: We reviewed our prospectively collected database of patients with cardiovascular implantable electronic devices (CIEDs) undergoing MRI between 2008 and 2017 at Mayo Clinic, Rochester, MN, and selected patients who had abandoned leads. We compared the adverse events in this population with an age, sex, and site of MRI-matched cohort of patients selected from this database. We evaluated paired (before/after) cTnT values using MRI in these patients.

RESULTS: Of 952 patients, 80 (8.4%) underwent 97 MRI scans with CIEDs in situ with 90 abandoned leads in place during the scans. The median age was 66 years (interquartile range 22.3 years) 66.1 years (interquartile range, Q1,Q3: 53.6, 75.9) with 66.3% (53 patients) men. There was no clinical or electrical evidence of CIED dysfunction, arrhythmias, or pain. Paired samples for the measurement of cTnT values were available in 40 patients undergoing 44 MRI examinations. The mean difference between the pre- and postimaging values was -0.002 ± 0.006 ng/mL (interquartile range 0). There was no difference after adjustment for total number of leads per patient and total number of implantable cardioverter-defibrillator coils.

CONCLUSION: There was no evidence of myocardial injury as measured by paired cTnT. The risk of MRI with abandoned leads appears low, suggesting a favorable risk-benefit profile in patients with CIEDs and abandoned leads who are considered for MRI.