Ultrahigh-density mapping for evaluation of antral scar extension after ablation with radiofrequency balloon catheter in atrial fibrillation patients

To achieve pulmonary vein isolation (PVI) fast and effectively, various 'single-shot' devices were developed, aiming at creating wide antral circumferential lesions. In this multicenter study we assessed the extension of the antral scar in patients undergoing their first PVI by mean of a RF balloon (Heliostar, Biosense Webster, Inc.) The ultra-high density voltage maps, before and after ablation, were acquired in sinus rhythm, using an octa spline mapping catheter (Octaray, Biosense Webster, Inc.). Areas with electrograms showing voltages > 0.5 mV were considered healthy and unablated tissue, with voltages < 0.2 mV were considered dense scar tissue and with voltages between 0.2 and 0.5 mV were defined as damaged but viable tissue ( 1 Spera F. Narducci M.L. Bencardino G. et al. Ultra-high-resolution assessment of lesion extension after cryoballoon ablation for pulmonary vein isolation. Front Cardiovasc Med. 2022 Nov 9; 9985182 Crossref Scopus (0) Google Scholar ). The pulmonary vein (PV) ostium was identified as the point of maximal inflection between the PV wall and left atrium (LA) wall, the PV antrum was defined as the circumferential area beginning at the PV ostium and reaching 5 mm into the LA, whereas the left atrium posterior wall (LAPW) was defined as the area delimited by two horizontal lines connecting superiorly the most superior aspect of the superior PVs ostia and inferiorly the most inferior aspect of the inferior PVs ostia, thus encompassing the posterior PV antra. The non-ablated LAPW area was defined as the area bordered by the PV lesions and two lines connecting the most superior and inferior aspects of the circumferential ablation lines (L1 and L2, respectively) ( 1 Spera F. Narducci M.L. Bencardino G. et al. Ultra-high-resolution assessment of lesion extension after cryoballoon ablation for pulmonary vein isolation. Front Cardiovasc Med. 2022 Nov 9; 9985182 Crossref Scopus (0) Google Scholar , 2 Gunawardene M.A. Schaeffer B.N. Jularic M. et al. Pulsed-field ablation combined with ultrahigh-density mapping in patients undergoing catheter ablation for atrial fibrillation: Practical and electrophysiological considerations. J Cardiovasc Electrophysiol. 2022; 33: 345-356 Crossref PubMed Scopus (29) Google Scholar , 3 Kawamura I. Neuzil P. et al. Does pulsed field ablation regress over time? A quantitative temporal analysis of pulmonary vein isolation. Heart Rhytm. 2021; 18: 878-884 Abstract Full Text Full Text PDF PubMed Scopus (0) Google Scholar ) (Figure). Low voltage areas <0.5 mV already present before PVI were excluded from the measurement of the ablated area after the ablation. The research reported in this paper adhered to Helsinki Declaration as revised in 2013 and was approved by the local Ethical Committee.