Key result
Contact Index-guided pulsed field ablation eliminates acute pulmonary vein gaps vs standard ablation.
Why the study?
Pulsed field ablation for AF requires adequate catheter-tissue contact, but a validated Contact Index impedance-change threshold to prevent acute pulmonary vein gaps was unknown.
Does Contact Index-guided pulsed field ablation using a >=10% impedance change threshold prevent acute pulmonary vein gaps on post-procedural voltage mapping compared to unguided ablation in patients with atrial fibrillation?
Cohort (n=36)
During Phase 1, impedance change values were blinded to the operators
No
Does Contact Index-guided pulsed field ablation using a >=10% impedance change threshold prevent acute pulmonary vein gaps on post-procedural voltage mapping compared to unguided ablation in patients with atrial fibrillation?
Enforcing a real-time impedance change threshold of >=10% on the EnSite X Contact Index during pentaspline pulsed field ablation eliminates acute pulmonary vein gaps at the vein and segment levels without increasing overall procedure or fluoroscopy times.
Answers are grounded in this paper and cite their sources.
Enforcing ≥10% impedance change may reduce acute PV gaps in PFA; leaves open whether this improves durable isolation or AF outcomes.
Background Pulsed field ablation (PFA) for atrial fibrillation (AF) requires adequate catheter–tissue contact. The Contact Index visualizes impedance change for the pentaspline catheter, but a validated contact threshold is unknown. Objective The objective of this study is to define an impedance‐change cutoff that predicts sufficient contact to prevent acute pulmonary vein gaps (PVG) during pulmonary vein isolation (PVI), and to validate Contact–Index‐guided PVI. Methods A prospective, single‐center, two‐phase study was performed. Phase 1 ( n = 10) measured impedance change (%) at eight antral segments per vein immediately before PFA in basket and flower configurations; the larger per‐segment value was analyzed. Post‐PVI high‐density voltage mapping (PVG ≥ 0.5 mV) was the reference; a receiver operating characteristic analysis identified the cutoff. Phase 2 ( n = 26) delivered energy only when all target splines met/exceeded the cutoff value obtained from Phase 1. Results In Phase 1, PVG occurred in 13/320 segments across 2/10 patients (4/40 veins). Impedance change was lower at PVG‐positive than PVG‐negative segments (median 2 [0–6.5]% vs. 24 [17–32]%, p < 0.001). The cutoff value obtained from Phase 1 was ≥ 10% (area under the curve 0.99; sensitivity 100%; specificity 92.1%). In Phase 2, enforcing ≥ 10% yielded no patient‐level PVG (0/26 vs. 2/10; p = 0.07) and fewer gaps per vein (0/104 vs. 4/40; p = 0.005) and per segment (0/832 vs. 13/320; p < 0.001) compared with Phase 1. Procedure time, PVI time, fluoroscopy time, and total applications were similar between phases. Conclusions An impedance‐change threshold of ≥ 10% on the Contact Index reliably indicates adequate contact with the pentaspline catheter and, when enforced, reduces acute PVG without prolonging procedures.
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Watanabe et al. (2026) conducted a cohort in Atrial fibrillation undergoing pulsed field ablation for pulmonary vein isolation (n=36). Contact Index-guided pulsed field ablation enforcing an impedance-change threshold of >=10% on all target splines vs. Pulsed field ablation guided by intracardiac echocardiography, fluoroscopy, and local electrograms with operators blinded to Contact Index (Phase 1) was evaluated on Acute pulmonary vein gaps (residual bipolar voltage >=0.5 mV on post-PVI high-density voltage mapping) per vein (p=0.005). Contact Index-guided pulsed field ablation enforcing an impedance change >=10% reduced acute pulmonary vein gaps per vein from 10% to 0% (p=0.005) and per segment from 4.1% to 0% (p<0.001).
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