Comparison of Monopolar and Bipolar Pulsed Field vs Radiofrequency Ablation on Coronary Artery Injury in a Swine...

Pulsed field ablation (PFA) has the advantage of tissue selectivity but is known to cause coronary artery (CA) spasm and injury. The effect of changes in PFA waveform on CA injury has not been adequately explored.

This study sought to explore the effects of varying PFA waveform (bipolar vs monopolar) and field strength (1.4 kV vs 2.0 kV) on CA injury compared with radiofrequency ablation (RFA) in a swine model.

Twelve swine underwent cavotricuspid isthmus (CTI) ablation using either biphasic PFA or a novel, dual-energy catheter without nitrate prophylaxis in 4 groups: 1) monopolar PFA 1.4 kV (PF-M1); 2) monopolar PFA 2.0 kV (PF-M2); 3) bipolar PFA 2kV (PF-B2); or 4) irrigated, contact-force RFA. High density mapping during differential pacing was performed to confirm bidirectional CTI block. CA angiography was performed prior to and immediately after CTI ablation and then at regular intervals. Swine were survived for 4 weeks and then underwent sacrifice and detailed histology.

Acute CA spasm occurred with 100% PFA deliveries regardless of catheter or waveform; luminal CA narrowing was greater with PFA than RFA (PF-M1 = 58.5%, PF-M2 = 68.8%, PF-B2 = 66.6%, radiofrequency = 10.2%). At 30 days, there was no angiographic CA stenosis, but mild CA injury characterized by neointimal hyperplasia and tunica media fibrosis was noted in 2 of 3 PF-M1, 2 of 3 PF-M2, 1 of 3 PF-B2, and 2 of 3 radiofrequency swine. There was no correlation between %CA spasm and injury (r² = 0.07, P = 0.4).

Acute CA spasm occurs more often with PFA than RFA, but similar chronic, mild CA injury may occur with both modalities. There is no correlation between the degree of acute spasm and chronic CA injury.