Characterization of Phrenic Nerve Response to Pulsed Field Ablation

Area of Science:

• Cardiac electrophysiology
• Medical device technology
• Nerve injury research

Background:

• Phrenic nerve palsy is a known complication of traditional thermal cardiac ablation.
• Pulsed field ablation (PFA) is an emerging technology with potential to reduce phrenic nerve injury.
• The impact of PFA on phrenic nerve function requires further characterization.

Purpose of the Study:

• To investigate the acute and chronic effects of pulsed field ablation (PFA) on phrenic nerve function in a porcine model.
• To establish a dose-response relationship between PFA energy delivery and phrenic nerve response.
• To evaluate the safety of PFA for cardiac procedures concerning phrenic nerve integrity.

Main Methods:

• Utilized accelerometers and continuous pacing during PFA in a porcine model.
• Established acute dose-response by escalating PFA intensity to the phrenic nerve (n=12).
• Assessed acute effects of repetitive ablations (n=4) and chronic histopathology (n=6).

Main Results:

• Observed a dose-dependent, reversible stunning of phrenic nerve function acutely (R²=0.965, P<0.001).
• PFA effects varied with energy levels and catheter proximity, ranging from no effect to stunning.
• Successful superior vena cava isolation with appropriate PFA dosing showed normal phrenic nerve function and histopathology at 4 weeks.

Conclusions:

• Catheter proximity and PFA dose are critical factors influencing phrenic nerve response.
• No gross or histopathologic injury to phrenic nerves was found at chronic time points.
• Results support understanding PFA's impact on nerves and necessitate caution when translating to human studies.