Acute pacing threshold elevation during simultaneous Micra leadless pacemaker implantation and AV node ablation:...

Area of Science:

• Cardiology
• Electrophysiology
• Medical Devices

Background:

• Refractory atrial fibrillation (AF) often necessitates atrioventricular nodal (AVN) ablation and permanent pacemaker implantation.
• The Micra Transcatheter Pacing System (Micra) is a leadless pacemaker (LPM) enabling potential AVN ablation during the same procedure.
• Pacing threshold (PT) elevation post-radiofrequency (RF) ablation is a known complication.

Purpose of the Study:

• To evaluate the safety and potential complications of concurrent AVN ablation with Micra implantation.
• To identify factors contributing to pacing threshold elevation after RF AVN ablation in patients with Micra.

Main Methods:

• A retrospective cohort study of 84 patients implanted with Micra, including 12 who underwent AVN ablation.
• Analysis of procedural characteristics and electrophysiological parameters.
• Computer modeling to investigate causes of acute PT elevation.

Main Results:

• Two out of 12 patients (16.7%) experienced acute PT elevation requiring Micra retrieval and replacement.
• Computer modeling indicated electrical field coupling can cause PT elevation if the ablation catheter is within 35 mm of the Micra at 100 W.
• No direct contact between ablation catheter and Micra was observed in the complication cases.

Conclusions:

• Concurrent AVN ablation and Micra implantation is generally safe.
• A minimum distance of 35 mm between the ablation catheter electrodes and the Micra, along with reduced power settings, can prevent acute PT elevation.