AUTHOR=Campos-García Bieito , Alonso-Martín Concepción , Guerra José M. , Moreno-Weidmann Zoraida , Méndez-Zurita Francisco , Montiel-Quintero Rodolfo , Betancur-Gutiérrez Andrés , Viñolas-Prat Xavier , Rodríguez-Font Enrique 

TITLE=Reassessment of the electrical connection between the pulmonary veins and the left atrium: A study to determine the different contributions of myocardial fibers along the standard ablation circumference

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 10 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2023.1162197

DOI=10.3389/fcvm.2023.1162197

ISSN=2297-055X

ABSTRACT=Background: Circumferential ablation around ipsilateral pulmonary veins (PVs) is the standard strategy for atrial fibrillation ablation. The present study sought to assess which regions of the standard ablation circumference are the main contributors to the venoatrial electrical connection.
Methods: Forty-one patients underwent a specific atrial fibrillation ablation protocol in which the anterior and posterior segments of the standard circumference, between the equatorial line of the superior and the inferior ipsilateral PVs, were ablated first. If PV isolation was not achieved, ablation was extended superiorly or inferiorly, based on the earliest atrial activation recorded during pacing from inside the PV. Complete PV isolation and the length of the areas non-requiring ablation (ANRA) at the time of electrical isolation were evaluated. 
Results: Ablation of the anterior and posterior segments of the standard circumference led to isolation of 77% left-PV pairs and 51% right-PV pairs (p=0,015). A superior extension was required in 23% left-PV pairs and in 46% right-PV pairs, while an inferior extension was required only in 10% left-PV pairs and in 11% right-PV pairs. PV isolation was achieved before completing the standard ablation circumference in 97% left-PV pairs and in 94% right-PV pairs, with a median ANRA of 36,9 (IQR 30,9 – 42,1) mm in the left PVs [16,0 (IQR 12,0 – 19,0) mm superior and 18,8 (IQR 16,1 – 24,9) mm inferior, p<0,01] and 36,9 (IQR 30,2 – 41,0) mm in the right PVs [15,1 (IQR 10,7 – 19,1) mm superior and 20,6 (IQR 16,9 – 23,3) mm inferior, p<0,01].
Conclusions: The myocardial fibers along the anterior and posterior regions of the standard ablation circumference are the main contributors to the electrical connection between the pulmonary veins and the left atrium. Ablation of these regions results in PV isolation in the majority of patients.