Modifying the trajectory of epicardial leads can substantially reduce MRI-induced RF heating in pediatric patients with a cardiac implantable electronic device

Abstract

Purpose: Infants and children with congenital heart defects, inherited arrhythmia syndromes, and congenital cardiac conduction disorders often receive epicardial implantable electronic devices. Unfortunately, once an epicardial device is implanted, the patient is no longer eligible to receive MRI exams due to an elevated risk of RF heating. Here we show that a simple modification in the trajectory of epicardial leads can substantially and reliably reduce RF heating during MRI at 1.5 T, with benefits extending to abandoned leads. Methods: Electromagnetic simulations were performed to assess RF heating of two common epicardial lead trajectories exhibiting different degrees of coupling with MRI incident electric fields. Experiments in anthropomorphic phantoms implanted with commercial cardiac implantable electronic devices (CIEDs) confirmed the findings. Results: Simulations of an epicardial lead with a trajectory where the excess length of the lead was looped and placed on the anterior surface of the heart showed a 9-fold reduction in 0.1g-averaged SAR compared to the lead with excess length looped on the inferior surface of the heart. Repeated experiments with a commercial epicardial device confirmed the results, showing a 16-fold reduction in the average temperature rise for fully implanted systems with leads following low-SAR trajectories, and a 20-fold reduction in RF heating on an abandoned lead. Conclusion: Surgical modification of epicardial lead trajectory can substantially reduce RF heating at 1.5 T, with benefits extending to abandoned leads.