https://doi.org/10.1007/s00392-025-02737-x
1Universitäres Herz- und Gefäßzentrum Hamburg Klinik für Kardiologie Hamburg, Deutschland; 2Helmsley Electrophysiology Center, Mount Sinai Fuster Heart Hospital, Icahn School of Medicine at Mount Sinai New York, USA; 3Institute of Physiology, First Faculty of Medicine, Charles University, Prague, Czech Republic Prague, Tschechische Republik; 4Na Homolce Hospital Prague, Tschechische Republik
Background:
Preclinical studies of pulsed field ablation (PFA) systems have indicated the absence of esophageal effects by ablation. However, esophageal assessments are typically performed weeks after PFA delivery, precluding an understanding of acute effects.Objectives:
To understand the mechanism of esophageal safety with PFA, using a combination of preclinical and clinical assessments.
Methods:
The porcine esophagus was manually displaced toward the inferior vena cava (IVC) using a balloon catheter. From within the IVC, a pentaspline PFA catheter delivered 4 stacked applications at 4-7 sites per animal. Animals were sacrificed either early (1 day; n=4) or late (14 days; n=2), followed by pathological assessment. PFA’s mechanical effect was determined in preclinical and clinical studies by contrast fluoroscopy of the esophagus during left atrial PFA.
Results:
After 1 day, 3 of 4 (75%) animals demonstrated esophageal lesions, measuring 5-32 mm long, 2-13 mm wide, and 2-3 mm deep. All lesions were non-transmural, with myocyte degeneration and leucocyte infiltration on histology; the mucosa and blood vessels were spared. The esophageal tissue architecture remained intact. Conversely, the 14-day cohort exhibited no lesions upon gross necropsy or histology. During atrial PFA using a variety of catheter technologies, esophageal contraction occurred such that it functionally retracted away from the point of ablation.
Conclusions:
The pentaspline PFA catheter creates acute non-transmural esophageal lesions, but these resolve by 14 days. The “functional sparing” of the esophagus during PFA is not an absolute lack of effect on the esophagus, but rather is due to a combination of favorable tissue healing and, likely, some degree of esophageal contraction/retraction.
Figure: Is the esophagus spared during pulsed field ablation? Left panel: Preclinical results from porcine experiments using an esophagus deviation model. The fluoroscopy image shows the pentaspline catheter within the IVC, deflected towards the esophagus. The dark, contrast-filled balloon catheter and esophagus were deviated towards the IVC. Bottom left: PFA-induced, non-transmural lesions (yellow dotted lines) were observed 24h after ablation, with spared blood vessels and preserved tissue architecture. No lesions were found 2 weeks after ablation (bottom right). Right panel: Esophageal contraction/retraction observed in preclinical and clinical experiments. Fluoroscopy images before (left image) and during (right image) delivery of PFA within the left atrium illustrate the contraction/retraction of the contrast-filled esophagus (yellow dotted lines) away from the ablation catheter.