MRI Compatibility of Leadless Pacemakers

Introduction to Leadless Pacemaker Safety

The Medtronic Micra leadless pacemaker is MRI-conditional and can safely undergo MRI scanning at both 1.5T and 3.0T when manufacturer instructions are followed, as recommended by the American College of Cardiology 1
The Micra system carries substantially lower MRI-related risks compared to traditional transvenous pacemakers due to its unique design characteristics, including no transvenous leads, smaller device size, and no pulse generator pocket, as stated by the European Heart Rhythm Association 1

Before proceeding with MRI, verify the MRI-conditional status directly with the device manufacturer's specifications for the specific Micra model implanted, as advised by the Heart Rhythm Society 2, 1
Wait a minimum of 6 weeks post-implantation to ensure device position stabilization, though leadless pacemakers have no risk of lead dislodgement, as recommended by the European Society of Cardiology 2, 1
Perform device interrogation to record baseline parameters including impedance, capture threshold, sensing amplitude, and battery voltage, as suggested by the American Heart Association 2, 1

Continuous ECG monitoring throughout the entire procedure by qualified personnel is necessary, as stated by the American College of Cardiology 2
Follow the manufacturer's programming instructions, which typically involve automatic mode switching, as recommended by the Heart Rhythm Society 2

Re-interrogate the device and compare all parameters to baseline measurements immediately after MRI completion, as advised by the European Heart Rhythm Association 2

Conventional pacemakers carry Class IIb recommendations (less favorable benefit-risk ratio) for MRI and require mandatory electrophysiology consultation, as stated by the European Heart Journal 3, 4, 5
The Micra system eliminates most historical contraindications due to its leadless design, as recommended by the American College of Cardiology 1