Utility of the Tissue Proximity Indication Feature in Predicting Reconnection of Pulmonary Vein Isolation During Pulsed-Field Ablation

The electrode-tissue contact is important when creating durable pulsed-field ablation (PFA) lesions, and the tissue proximity indication (TPI) feature integrated into the VARIPULSE^TM catheter (Biosense Webster, CA, USA) provides information on the distance between the catheter electrodes and surrounding tissues via impedance measurement, highlighting the electrodes that have appropriate contact with the tissue. A recent animal study showed that TPI-based contact during PFA was strongly associated with chronic transmural lesions.¹

We report the case of an 81-year-old woman who underwent initial PFA for paroxysmal atrial fibrillation using a VARIPULSE catheter. After 54 PFA applications to the 4 pulmonary veins (PVs), left atrial (LA) mapping revealed residual potentials at the left superior PV (LSPV) ostium, while the other 3 PVs were isolated (Figure A,B). The site where residual potentials were observed corresponded to that where the PFA tags disappeared when the TPI filter feature was used (Supplementary Figure), suggesting inadequate contact during PFA application (Figure B). An additional 6 PFA applications to the LSPV were performed, resulting in transient elimination of the potential at the LSPV ostium; however, the TPI filter feature revealed that the gap site was not covered by additional applications (Figure C). LA mapping performed 1 h after LSPV isolation showed reconnection of the LSPV at the site where PFA tags were absent (Figure D). Another 6 PFA applications with adequate contact at the gap site successfully re-isolated the LSPV.

Figure.

(A) Before pulsed-field ablation (PFA), (B) after 54 applications, (C) after 60 applications and (D) 1 h later.

To our knowledge, this is the first report demonstrating the possible utility of the TPI feature in achieving PV isolation in humans. This case underscores the usefulness of monitoring the electrode-tissue contact using the TPI feature during PFA application. Further studies with a larger number of patients are needed to confirm the utility of this feature.

Conflict of Interests

None.

Funding

This work was supported by JSPS KAKENHI (Grant Number JP24K11205).

IRB Information

The present study was approved by the National Cerebral and Cardiovascular Center (Reference number: M26-148-16).

Supplementary Files

Please find supplementary file(s);

https://doi.org/10.1253/circrep.CR-24-0107

Reference

• 1.   Okumura Y, Watanabe R, Nagashima K, Wakamatsu Y, Byun E, Chen Q, et al. In vivo assessment of catheter-tissue contact using tissue proximity indication and its impact on cardiac lesion formation in pulsed field ablation. Heart Rhythm 2024, doi:10.1016/j.hrthm.2024.09.061.