Pulsed-Field Ablation: Proximity to Coronary Vessels and the Unresolved Issue of Induced Vasospasm

Pulsed-field ablation (PFA) has emerged as a promising technique in the treatment of atrial fibrillation, thanks to its ability to generate precise myocardial lesions with a superior safety profile compared to conventional ablation. It is a non-thermal method with greater tissue specificity.

However, its extrapulmonary application—such as in the cavotricuspid isthmus (CTI) or the mitral isthmus (MI)—has raised concerns in early studies, given the possibility of coronary spasm due to the proximity of these structures to epicardial coronary vessels.

In this context, Tam et al. published an observational study that assessed, using OCT, the immediate and short-term structural changes in coronary arteries subjected to PFA.

Twenty-one patients treated with PFA for atrial flutter were included. Of them, 19 completed the imaging study series before, during, and three months after the procedure. As part of the protocol, nitroglycerin (NTG) was administered preventively in the corresponding arteries.

At three months, the ablation site showed significant increase in vascular wall area (WA), which rose from 2.69 mm² to 3.21 mm², equivalent to a 17.1-% remodeling (p <0.01). Additionally, the corrected lumen area (cLA) decreased from 6.92 mm² to 5.41 mm², accounting for a 10.1-% reduction (p <0.001).

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These structural changes were not detected at remote reference sites, where the vascular wall remained relatively unchanged (ΔWA: 0.12 mm²; p = 0.926) and the corrected lumen area remained stable.

As for acute coronary spasm, it was documented in 75% of vessels (mild, 15%; moderate, 15%; severe, 45%). Acute lumen reduction showed a nonsignificant trend toward correlation with lumen loss at three months (r = 0.41, p = 0.08), suggesting a possible pathophysiological link between spasm and vascular remodeling.

Although, in terms of percentage, the structural modifications at three months are not striking (10.1% in corrected lumen area), their clinical impact could be relevant in patients with preexisting coronary artery disease, by altering the prognosis of intermediate or severe lesions.

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While there were no major short-term events—such as myocardial infarction or cardiovascular death—prolonged monitoring is essential, as the long-term clinical effect of these PFA-induced structural changes remains unknown.

Conclusions

Pulsed-field ablation for atrial flutter (CTI/MI), when applied in proximity to coronary arteries, may induce subclinical vascular remodeling, which justifies the need for prolonged follow-up in this population. This study was the first to demonstrate, quantitatively and through serial OCT, a potentially adverse impact.

Original Title: Effect of Pulsed-Field Ablation on Human Coronary Arteries. A Longitudinal Study With Intracoronary Imaging.

Reference: Tam MTK, Chan JYS, Chan CP, Wu EB, Lai A, Au ACK, Chi WK, Tan G, Yan BP. Effect of Pulsed-Field Ablation on Human Coronary Arteries: A Longitudinal Study With Intracoronary Imaging. JACC Clin Electrophysiol. 2025 Jul;11(7):1478-1488. doi: 10.1016/j.jacep.2025.03.014. Epub 2025 Apr 24. PMID: 40278817.