MRI-conditional pacemakers: current perspectives

Abstract

Use of both magnetic resonance imaging (MRI) and pacing devices has undergone remarkable growth in recent years, and it is estimated that the majority of patients with pacemakers will need an MRI during their lifetime. These investigations will generally be denied due to the potentially dangerous interactions between cardiac devices and the magnetic fields and radio frequency energy used in MRI. Despite the increasing reports of uneventful scanning in selected patients with conventional pacemakers under close surveillance, MRI is still contraindicated in those circumstances and cannot be considered a routine procedure. These limitations prompted a series of modifications in generator and lead engineering, designed to minimize interactions that could compromise device function and patient safety. The resulting MRI-conditional pacemakers were first introduced in 2008 and the clinical experience gathered so far supports their safety in the MRI environment if certain conditions are fulfilled. With this technology, new questions and controversies arise regarding patient selection, clinical impact, and cost-effectiveness. In this review, we discuss the potential risks of MRI in patients with electronic cardiac devices and present updated information regarding the features of MRI-conditional pacemakers and the clinical experience with currently available models. Finally, we provide some guidance on how to scan patients who have these devices and discuss future directions in the field.

Keywords: MRI; MRI-conditional devices; magnetic resonance imaging; pacemakers; safety.

Figure 1

Balanced steady-state free precession (b-SSFP) cine images of the heart in a patient with an implanted magnetic resonance imaging-conditional pacemaker. Notes: Note the susceptibility artifacts from the pulse generator in left ventricular 2-chamber view (A) and from the right ventricular lead in short-axis view (B). Despite being clearly apparent, these artifacts don’t usually hinder diagnostic interpretation, except when the region of interest is in the proximity of the pacemaker generator.