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Local Impedance Drop Predicts Durable Conduction Block in Patients With Paroxysmal Atrial Fibrillation

Lookup NU author(s): Dr Ewan Shepherd, Dr Moloy Das



This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).


© 2022 The AuthorsObjectives: This analysis was performed to evaluate the transition of local impedance (LI) drop during pulmonary vein isolation (PVI) to durable block and mature lesion formation based on 3-month mapping procedures. Background: A radiofrequency catheter measuring LI has been shown to be effective for performing PVI in patients with paroxysmal atrial fibrillation. Previous analysis has demonstrated LI drop to be predictive of pulmonary vein segment conduction block during an atrial fibrillation ablation procedure. Methods: Fifty-eight patients who had undergone LI-blinded de novo PVI returned for a 3-month mapping procedure. PVI ablation circles were divided into 16 anatomic segments for classification (durable block or gap), and the median LI drop within segments with an interlesion distance of ≤6 mm was compared. A total of 51 data sets met the criteria for segmental analysis of LI performance. Results: At the 3-month procedure, PV connection was confirmed in at least 1 PV segment in 35 of the included patients. LI drop outperformed generator impedance drop as a predictor of durable conduction block (area under the receiver-operating characteristic curve: 0.79 vs 0.68; P = 0.003). Optimal LI drops were identified by left atrial region (anterior/superior: 16.9 Ω [sensitivity: 69.1%; specificity: 85.0%; positive predictive value for durable conduction block: 97.7%]; posterior/inferior:14.2 Ω [sensitivity: 73.8%; specificity: 78.3%; positive predictive value: 96.9%]). Starting LI before radiofrequency (RF) application was significantly different among healthy, gap, and mature scar tissue and was also a contributing factor to achieving an optimal LI drop (85.2% of RF applications with a starting LI of ≥110 Ω achieved the optimal regional drop or greater). Conclusions: LI drop is predictive of durable PV segment isolation. Preablation starting LI is associated with the magnitude of LI drop. These findings suggest that a regional approach to RF ablation guided by LI combined with careful interlesion distance control may be beneficial in patients with paroxysmal atrial fibrillation (Electrical Coupling Information From the Rhythmia HDx System and DirectSense Technology in Subjects With Paroxysmal Atrial Fibrillation [LOCALIZE]; NCT03232645)

Publication metadata

Author(s): Garcia-Bolao I, Ramos P, Luik A, S Sulkin M, R Gutbrod S, Oesterlein T, I Laughner J, Richards E, Meyer C, Yue A, Ullah W, Shepherd E, Das M

Publication type: Article

Publication status: Published

Journal: JACC: Clinical Electrophysiology

Year: 2022

Volume: 8

Issue: 5

Pages: 595-604

Print publication date: 16/05/2022

Online publication date: 23/02/2022

Acceptance date: 05/01/2022

Date deposited: 24/05/2022

ISSN (print): 2405-500X

Publisher: Elsevier Inc.


DOI: 10.1016/j.jacep.2022.01.009


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