The incidence and location of epicardial connections in the era of contact force guided ablation for pulmonary vein isolation

Abstract Background Contact force catheter ablation is the gold standard for treatment of atrial fibrillation (AF). Local tissue impedance (LI) evaluation has been recently studied to evaluate lesion formation during radiofrequency ablation. Purpose Aim of the study was to assess the outcomes of an irrigated catether with LI alghorithm compared to contact force (CF)-sensing catheters in the treatment of symptomatic AF. Methods A prospective, single-center, nonrandomized study was conducted, to compare outcomes between CF-AF ablation (Group 1) and LI-AF ablation (Group 2). For Group 1 ablation was performed using the Carto 3© System with the SmartTouch SF catheter and, as ablation target, an ablation index value of 500 anterior and 400 posterior. For Group 2, ablation was performed using the Rhythmia™ System with novel ablation catheter with a dedicated algorithm (DirectSense) used to measure LI at the distal electrode of this catheter. An absolute impedance drop greater than 20Ω was used at each targeted. According to the Close Protocol, ablation included a point by point pulmonary vein isolation (PVI) with an Inter-lesion space ≤5 mm in both Groups. Procedural endpoint was PVI, with confirmed bidirectional block. Results A total of 116 patients were enrolled, 59 patients in Group 1 (CF) and 57 in Group 2 (LI), 65 (63%) with a paroxismal AF and 36 (37%) with a persistent AF. Baseline patients features were not different between groups (P=ns). LI-Group showed a comparable procedural time (180±89 vs 180±56, P=0.59) but with a longer fluoroscopy time (20±12 vs 13±9 min, P=0.002). Wide antral isolation was more often observed in CF-Group (95% vs 80%, P=0.022), while LI-Group 2 required frequently additional right or left carina ablation (28% vs 14%, P=0.013). The mean LI was 106±14Ω prior to ablation and 92.5±11Ω after ablation (mean LI drop of 13.5±8Ω) during a median RF time of 26 [19–34] sec for each ablation spot. No steam pops or complications during the procedures were reported. The acute procedural success was 100%, with all PVs successfully isolated in all study patients. Regarding safety, only minor vascular complications were observed (5%), without differences between groups (p=0.97). During follow up, 9-month freedom from atrial fibrillation/atrial flutter/atrial tachycardia recurrence was 86% in Group 1 and 75% in Group 2 (P=0.2). Conclusions An LI-guided PV ablation strategy seems to be safe and effective, with acute and mid-term outcomes comparable to the current contact force strategy. LI monitoring could be a promising complementary parameter to evaluate not only wall contact but also lesion formation during power delivery. Procedural Outcomes Funding Acknowledgement Type of funding source: None

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The role of local impedance drop in the acute lesion efficacy during pulmonary vein isolation performed with a new contact force sensing catheter—A pilot study

PLoS ONE ◽

10.1371/journal.pone.0257050 ◽

2021 ◽

Vol 16 (9) ◽

pp. e0257050

Author(s):

Nándor Szegedi ◽

Zoltán Salló ◽

Péter Perge ◽

Katalin Piros ◽

Vivien Klaudia Nagy ◽

...

Keyword(s):

Pilot Study ◽

Pulmonary Vein ◽

Pulmonary Vein Isolation ◽

Contact Force ◽

Posterior Wall ◽

Anterior Wall ◽

Force Sensing ◽

Lesion Formation ◽

Force Time

Introduction Our pilot study aimed to evaluate the role of local impedance drop in lesion formation during pulmonary vein isolation with a novel contact force sensing ablation catheter that records local impedance as well and to find a local impedance cut-off value that predicts successful lesion formation. Materials and methods After completing point-by-point radiofrequency pulmonary vein isolation, the success of the applications was evaluated by pacing along the ablation line at 10 mA, 2 ms pulse width. Lesions were considered successful if loss of local capture was achieved. Results Out of 645 applications, 561 were successful and 84 were unsuccessful. Compared to the unsuccessful ablation points, the successful applications were shorter (p = 0.0429) and had a larger local impedance drop (p<0.0001). There was no difference between successful and unsuccessful applications in terms of mean contact force (p = 0.8571), force-time integral (p = 0.0699) and contact force range (p = 0.0519). The optimal cut-point for the local impedance drop indicating successful lesion formation was 21.80 Ohms on the anterior wall [AUC = 0.80 (0.75–0.86), p<0.0001], and 18.30 Ohms on the posterior wall [AUC = 0.77 (0.72–0.83), p<0.0001]. A local impedance drop larger than 21.80 Ohms on the anterior wall and 18.30 Ohms on the posterior wall was associated with an increased probability of effective lesion creation [OR = 11.21, 95%CI 4.22–29.81, p<0.0001; and OR = 7.91, 95%CI 3.77–16.57, p<0.0001, respectively]. Conclusion The measurement of the local impedance may predict optimal lesion formation. A local impedance drop > 21.80 Ohms on the anterior wall and > 18.30 Ohms on the posterior wall significantly increases the probability of creating a successful lesion.

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