Monocenter Investigation Micra® MRI study (MIMICRY): feasibility study of the magnetic resonance imaging compatibility of a leadless pacemaker system

Abstract

Aims\nAs in vivo real-life data are still scarce, we conducted a study to assess the safety and feasibility of cardiac magnetic resonance imaging (MRI) in patients with a leadless pacemaker system.\n\n\nMethods and results\nIn this prospective non-randomized interventional trial, we enrolled 15 patients with an MRI conditional Micra® leadless pacemaker system to undergo either a 1.5\u2009T or 3.0\u2009T cardiac MRI scan. Clinical adverse events as well as device parameters such as pacing threshold, sensing, impedance, and battery life were assessed at baseline as well as 1 and 3 months after the scan. Device parameter changes between different time points were tested for statistical significance and compared with pre-set cut-off values. Fourteen patients underwent the cardiac MRI scan according to the protocol as well as the scheduled follow-up visits. One participant was excluded from analysis, as the MRI scan was not possible because of severe claustrophobia. Other clinical events did not occur during the scan and the follow-up period. Device parameters stayed stable and changes during the observational period were statistically not significant (changes vs. baseline: pacing threshold: 0.01\u2009±\u20090.05\u2009V, P\u2009=\u20090.308, 0.01\u2009±\u20090.07\u2009V, P\u2009=\u20090.419, sensing: -0.15\u2009±\u20091.11\u2009mV, P\u2009=\u20090.658, -0.19\u2009±\u20091.17\u2009mV, P\u2009=\u20090.800, impedance: -7.86\u2009±\u200930.7 Ohm, P\u2009=\u20090.447, -7.86\u2009±\u200925.77 Ohm, P\u2009=\u20090.183, at 1 and 3 months follow-up, respectively). Parameter changes were not statistically different between patients who underwent imaging at 1.5\u2009T (n\u2009=\u20097) or 3.0\u2009T (n\u2009=\u20097).\n\n\nConclusion\nIn our set of patients with a Micra® leadless pacemaker, cardiac magnetic resonance imaging at either 1.5\u2009T or 3.0\u2009T proved feasible and safe with no relevant changes in device parameters within 3 months of follow-up.