Background Pulmonary vein (PV) antrum is the principal target in atrial fibrillation (AF) ablation. This study was designed to evaluate the PV antrum dimension using intracardiac echocardiography (ICE) and its relationship with left atrial (LA) volume measure by CT scan.

Methods Consecutive twenty patients with paroxysmal AF who underwent PV antrum isolation were evaluated. The PV antrum border (VB) was identified using ICE. The electrical PV os (VE) was determined by the most proximal point with atrial electrogram amplitude < 0.5 mV. The distance between VB and VE was measured on an electroanatomical mapping system (CARTO XP, Biosense Webster) and defined as the PV antrum length. Three sides of each PV were evaluated: superior, anterior, and posterior lengths for the superior PVs; inferior, anterior and posterior lengths for the inferior PVs. Total, anterior, and posterior LA volume was measured using 128-channel multi-detector CT scan.

Results Posterior lengths were longest in all 4 PVs: 16짹3.6, 14짹3.7, 20짹6.8, and 19짹5.3 mm for RSPV, RIPV, LSPV, and LIPV, respectively. Superior PVs had long superior lengths: 15짹4.8 and 18짹5.4 mm for RSPV and LSPV, respectively. Superior length of LSPV was correlated with the posterior LA volume (R=0.51, p=0.021). However posterior length of RSPV was inversely correlated with the total LA volume (R= -0.52, p=0.019).

Conclusion PV antrum dimension was especially large in superior and posterior sides. Therefore these regions might need more wide-area ablation. Inverse correlation of RSPV antrum dimension with LA volume and its meaning as a structural remodeling in paroxysmal AF need further investigation.