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. 2025 Apr;22(4):952-960.
doi: 10.1016/j.hrthm.2024.09.061. Epub 2024 Oct 2.

In vivo assessment of catheter-tissue contact using tissue proximity indication and its impact on cardiac lesion formation in pulsed field ablation

Yasuo Okumura  1 , Ryuta Watanabe  2 , Koichi Nagashima  2 , Yuji Wakamatsu  2 , Eric Byun  3 , Qi Chen  3 , Tara Gomez  3
Affiliations
Free article

In vivo assessment of catheter-tissue contact using tissue proximity indication and its impact on cardiac lesion formation in pulsed field ablation

Yasuo Okumura et al. Heart Rhythm. 2025 Apr.
Free article

Abstract

Background: No evidence exists regarding whether tissue proximity indication (TPI), an impedance-based contact indicator, can improve in vivo lesion formation and durability during pulsed field ablation (PFA).

Objective: This in vivo study investigated the relationship between catheter-tissue contact and lesion formation.

Methods: In 5 porcine subjects, PFA applications were delivered at 35 atrial target sites using the VARIPULSE variable-loop circular catheter with the CARTO 3 mapping system. We compared acute ablative low-voltage zones (LVZs; <0.5 mV), chronic LVZs, and pathologic lesions between no/minimum contact (TPI-negative/flickering TPI-positive status) and consistent tissue contact (consistent TPI-positive status) for typical clinical scenarios and tissue tenting (TPI-positive status with electrodes extensively away from the 3-dimensional mapping surface) for safety margin. Ultrasound imaging also confirmed contact category assessments.

Results: Acute and chronic LVZs were significantly larger with consistent contact compared with no/minimum contact, including pathologic lesion length (36.0 ± 12.5 mm vs 17.4 ± 15.2 mm; P = .002) and maximum width (10.3 ± 2.7 mm vs 5.7 ± 5.1 mm; P = .035); results with tenting (length: 34.6 ± 11.7 mm; width: 11.3 ± 1.9 mm) were comparable to consistent contact. Lesion transmurality was achieved in all lesions with consistent contact or tissue tenting but only in 54.5% with no/minimum contact (P = .001 for each). The TPI-based electrode contact distance, measured as the cumulative length of the multielectrode catheter tip positive for TPI, significantly correlated with lesion length, maximum width, and transmurality.

Conclusion: Consistent TPI-based contact during PFA was strongly associated with distinct chronic transmural lesions, emphasizing the importance of tissue contact in optimizing circumferential lesion formation with circular PFA catheters.

Keywords: Atrial fibrillation; Catheter ablation; Contact indicator; Pulmonary vein; Pulsed field ablation.

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Conflict of interest statement

Disclosures Dr Okumura received research funding from Bayer Healthcare and Biosense Webster, Inc; received a scholarship grant from Boston Scientific Japan; received speaker honoraria from Daiichi Sankyo, Bayer Healthcare, Bristol Myers Squibb, Ono Pharmaceutical, Johnson & Johnson/Biosense Webster, Inc, and Medtronic Japan; and is affiliated with endowed courses from Boston Scientific Japan, Japan Lifeline, Fukuda Denshi, Abbott Medical Japan, Biotronik Japan, and Medtronic Japan. Mr Byun, Dr Chen, and Dr Gomez are employees of Biosense Webster, Inc. Drs Watanabe, Nagashima, and Wakamatsu have no conflicts of interest to disclose.

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