The correlation between local impedance drop and catheter contact in clinical pulmonary vein isolation use

Abstract

Introduction Local impedance (LI) drop during radiofrequency (RF) application is monitored to assess the lesion formation. Recently, a novel ablation catheter has been introduced to clinical setting, which is capable of monitoring LI and catheter contact parameters including contact force (CF) and contact angle (CA). This study aimed to clarify the correlation between LI drop and catheter contact parameters. Methods and results This prospective study included 15 paroxysmal atrial fibrillation (AF) patients who underwent initial pulmonary vein isolation (PVI). First‐pass encircling point‐by‐point PV ablation was performed by using a 4.5‐mm irrigated ablation catheter, with monitoring LI, CF, and CA. RF energy was applied for 30 s at each site with 30 W. Stable ablation points were analyzed to examine the correlation between LI drop and catheter contact parameters. Among 903 ablation points, 499 stable ablation points (55.2%) were analyzed. CA showed good correlation with LI drop (ρ = 0.418, p < .001). Maximum CF, minimum CF, average CF, and initial CF all showed weak correlation with LI drop (ρ = 0.201, p < .001; ρ = 0.224, p < .001; ρ = 0.258, p < .001; and ρ = 0.212, p < .001, respectively). Multivariate analysis demonstrated that CA was an independent factor of LI drop among the catheter contact parameters (β = 0.139, 95% CI = 0.111–0.167, p < .001). The LI drop in the blocked segments was significantly higher than that in the electrical conduction gap segments (27.3 ± 9.8 vs. 19.6 ± 6.4 Ω, p < .001) Conclusion In clinical PVI use, both CF and CA were correlated with LI drop. More parallel CA could induce higher LI drop, which may lead to effective lesion formation.

Combined contact force and local impedance dynamics during repeat atrial fibrillation catheter ablation

“…Reconduction over previous linear or substrate ablation and development of new low voltage areas are frequent findings during repeat AF ablation, while persistent conduction blocks have been reported to be present in only 21% using conventional ablation setups (Huo et al, 2020). Therefore, index and repeat ablation procedures as well as ablation within healthy compared to impaired myocardium need to be distinguished when evaluating LI and CF dynamics: In our analysis, baseline LI was lower compared to previous results on index AF procedures, but LI correlated better with ΔLI compared to CF which is in line with published data (Szegedi et al, 2021;Ikenouchi et al, 2022;Solimene et al, 2022;Yasumoto et al, 2022). Furthermore, baseline LI was lower compared to blood pool LI in 45% of RFC applications, whereas an elevation of tissue baseline LI beyond blood pool LI was observed in index AF procedures (Solimene et al, 2022).…”

“…Several experimental and clinical studies have recently been published reporting experiences of combined CF and LI assessment during index AF ablation (Szegedi et al, 2021;Gutbrod et al, 2022;Solimene et al, 2022;Yasumoto et al, Frontiers in Physiology frontiersin.org 2022). Single-shot devices have seen increased usage for index AF ablations in recent years (Mulder et al, 2021).…”

Monitoring Spike Potential and Abrupt Impedance Rise with Concomitant Temperature/Contact Force Change for Timely Detection of the Occurrence of “Silent” or “Nonaudible” Steam Pop

“…Te decrease in impedance during RFCA application is assumed to be the result of ion mobility [12,13]. Several studies have reported that the magnitude of the impedance drop predicts acute PVI [14][15][16]. An impedance drop of >15-18 ohm was found to be associated with an increased risk of SP occurrence [17,18].…”

Radiofrequency lesion formation prediction with contact force versus local impedance

“…Utility of combined local impedance and contact force during RF ablation of atrial fibrillation. ), http://links.lww.com/HCO/A93] [16,21 ▪▪ ,23 ▪ ].…”