CT evaluation of pulmonary venous anatomy variation in patients undergoing catheter ablation for atrial fibrillation.

To characterize pulmonary vein (PV) anatomy and the relative position of the PV ostia to the adjacent thoracic vertebral bodies, two readers reviewed 176 computed tomography pulmonary venous studies. PV ostial dimensions were measured and PV ovality assessed. Anatomical variations in PV drainage were noted. The position of the PV ostium relative to the nearest vertebral body edge was recorded. Right PV ostia were significantly more circular than the left (p<.001). Anatomical variability was greater for right PVs: 82% of patients had 2 ostia, 17% had 3 ostia, 0.5% had 4 ostia and 0.5% a common ostium. For left PVs, 91% of patients had 2 ostia, 8.5% a common ostium and 0.5% 3 ostia. Mean ostial distances from vertebral margin were: right PVs 3.62±7.48 mm; left PVs 3.84±8.46 mm (p=.72). 65% of right upper PV, 60.5% of right lower PV, 51% of left upper PV and 57% of left lower PV ostia were positioned lateral to vertebral bodies. Right PV ostia are rounder than left-sided and right PV drainage is more variable. As a significant proportion of PV ostia overlap the vertebral bodies, prior anatomical evaluation by CT can assist catheter ablation procedures for atrial fibrillation (AF), especially when performed under fluoroscopy.