MRI Compatibility of Leadless Pacemakers

Leadless pacemakers are MRI-conditional and can safely undergo MRI scanning at 1.5T when following manufacturer's specific instructions. 1

Understanding MRI Compatibility for Cardiac Devices

MRI-conditional devices: Specifically designed and tested to be safe in the MRI environment under defined conditions 2
Conventional (non-MRI-conditional) devices: Traditional pacemakers and ICDs that historically carried contraindications for MRI 2

Leadless pacemakers are generally designed to be MRI-conditional, allowing patients to safely undergo MRI scanning at 1.5T 1
The absence of transvenous leads (which are prone to heating during MRI) makes leadless pacemakers inherently less susceptible to MRI-related complications 2
Manufacturer's instructions must be strictly followed to ensure patient safety during MRI procedures 2

Verify the specific device model is MRI-conditional 1
Device should be implanted for at least 6 weeks before MRI to ensure proper position stabilization 2
Device interrogation should be performed to record baseline parameters (impedance, threshold, battery voltage) 2
Programming may be required according to manufacturer specifications 1

Continuous cardiac monitoring is essential throughout the procedure 1
Qualified personnel should be present to handle any potential emergencies 3
MRI should be limited to 1.5T field strength, as no information exists for safety at higher field strengths (e.g., 3T) 2

Device interrogation should be performed immediately after MRI to verify proper function 2
Compare post-MRI parameters with baseline values 2
Restore original programming if changes were made for the MRI procedure 2

No risk of lead dislodgement during MRI (a concern with conventional transvenous leads) 2
No lead heating issues that typically affect conventional pacemakers 4
Reduced risk of device-MRI interactions due to smaller size and absence of pocket/lead system 1

Although rare, potential adverse effects could include:
- Changes in device settings or programming 2, 5
- Temporary sensing or pacing threshold changes 5, 4
- Theoretical risk of device movement (though extremely rare with leadless devices) 2

Performing MRI before the 6-week maturation period after implantation 2
Failing to follow manufacturer-specific instructions for the particular device model 1
Neglecting to perform pre- and post-MRI device checks 2
Using MRI field strengths higher than those tested and approved (typically >1.5T) 2

Recent studies demonstrate that properly managed MRI procedures are safe for patients with cardiac devices, including leadless pacemakers 5, 4
A large study of 1,500 patients with cardiac devices (including 1,000 with pacemakers) showed no deaths, lead failures, or ventricular arrhythmias during properly conducted MRI procedures 5
Evidence suggests that even with non-MRI conditional leads, when following recommended protocols, MRI can be performed safely 4