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The effect of varying irrigation flow-rate during irrigated radiofrequency ablation on optimising lesion shape

Lookup NU author(s): Dr Rachael Redgrave, Dr Anna Walaszczyk, Micheylla Dewi, Dr Maria Camacho EncinaORCiD, Dr Gavin RichardsonORCiD, Dr Moloy Das



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Background: Irrigated radiofrequency lesions show a "teardrop" shape, due to endocardial sparing, requiring extensive lesion overlap for contiguity at the endocardial surface. The effect of dynamic irrigation rate on lesion-shape has not been studied.Objective: To assess if dynamic irrigation flowrate during radiofrequency ablation optimises lesion shape by minimising endocardial sparing. Methods:Ex vivo porcine heart model (Phase 1), irrigated ablation lesions were performed in ventricular tissue at 30W with 5 different irrigation protocols A) fixed-rate; B) continuous-reduction; C) continuous-increase; D) stepwise-reduction; E) stepwise-increase. Contact force (10g) and ablation duration (30sec) were constant. Lesion dimensions and endocardial sparing were measured. The optimal protocol was further tested at 20-40W. In Phase 2, the optimal protocol was tested using a in vivo large animal model.Results: Phase 1: Across power settings of 20-40W, continuous reduction in flowrate (B) resulted in decreased endocardial sparing area with maintained lesion depth and volume, compared to fixed-rate irrigation (P<0.001). Phase 2: 65, 30sec lesions were completed in 4 anaesthetised pigs using protocol B (n=25) or fixed-rate irrigation (n=40). The maximum recorded tip temperature was higher for continuous reduction in both the atrium and ventricle but there were no steam pops for either protocol.Conclusions: Compared to fixed-rate, continuous-reduction in irrigation flowrate from 30 to 2ml/min during irrigated radiofrequency ablation results in an optimised lesion shape with reduced endocardial sparing across power settings (20-40W) and proved feasible in an in vivo setting. This may allow for greater lesion spacing while maintaining endocardial contiguity clinically.

Publication metadata

Author(s): Redgrave R, Walaszczyk A, Dewi MW, Encina MC, Clemens J, Matrins R, Richardson GD, Das M

Publication type: Article

Publication status: Published

Journal: EP Europace

Year: 2024

Volume: 26

Issue: 1

Print publication date: 01/01/2024

Online publication date: 27/10/2023

Acceptance date: 11/10/2023

Date deposited: 26/07/2023

ISSN (print): 1099-5129

ISSN (electronic): 1532-2092

Publisher: Oxford University Press


DOI: 10.1093/europace/euad321


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Funder referenceFunder name
Investigator Sponsored Research Grant from Boston Scientific (Ref: ISRRM110379).