Role of multidetector computed tomography in the anatomical definition of the left atrium-pulmonary vein complex in patients with atrial fibrillation. Personal experience and pictorial assay

Abstract

This study aimed to illustrate the typical anatomical pattern and anatomical variants of the left atrium-pulmonary vein (LA-PV) complex studied by 16-slice multidetector computed tomography (MDCT) in a population of patients with atrial fibrillation (AF) undergoing percutaneous transcatheter left atrial ablation. Accurate knowledge of this anatomical region is fundamental for increasing the efficiency, efficacy and accuracy of the procedure and for reducing the risk of complications. From January 2004 to March 2007, we studied 75 patients (57 men, 18 women) affected by paroxysmal and chronic AF by using MDCT. In 63 patients, the MDCT examination was performed using retrospective cardiac electrocardiographic (ECG) gating and dose modulation, with reconstructions performed at 75% of R-R interval. In the remaining 12 patients, ECG gating was not possible due to high-frequency AF. We identified 286 PV: 157 right and 129 left. On the right side, eight PV were supernumerary and one was a common trunk, whereas on the left side, we found 22 common trunks and one supernumerary vein. In 61.3% of patients, the anatomical pattern was typical (two right and two left PV). In the remaining 38.7%, it was atypical [two right PV-left common trunk (26.6%); three right PV-two left PV (6.7%); three right PV-left common trunk (2.6%); three right PV-three left PV (1.3%); right common trunk-two left PV (1.3%)]. MDCT identified branching of the right inferior PV in 94.5%, of the right superior PV in 75.6%, of the left superior PV in 7.5% and of the left inferior PV in 7.5%; 3/8 of the right supernumerary veins presented branching. With respect to the left PV ostia, the position of the orifice of the 74 recognised appendages was high in 85.1%, intermediate in 12.1% and low in 2.8%. There was no association between PV anatomical variants and clinical presentation of AF (paroxysmal or chronic). MDCT represents a fundamental diagnostic imaging tool in the anatomical definition of the LA-PV complex, which is characterised by considerable variability. Radiologists must be familiar with the anatomical variants and help the referring interventional electrophysiologist understand their importance.