Common trunk of the right and left inferior pulmonary veins: Previously unreported anatomic variant with implications for catheter ablation

Knowledge of individual pulmonary vein (PV) anatomy is a prerequisite for effective and safe catheter ablation of atrial fibrillation. ^{,  ,}  The majority of PV anatomic variants, such as left common PV trunks and right middle PV, can be detected reliably by intraprocedural venography. Other variants are more difficult to diagnose. We describe the case of a highly unusual, previously unreported anatomic variant that required preprocedural computed tomographic (CT) scan with three-dimensional reconstruction for diagnosis as well as a modified ablation approach. The patient was a 53-year-old man with lone paroxysmal atrial fibrillation for 8 years. Preprocedural imaging was performed using a multidetector CT scanner (Philips, The Netherlands) and nonionic contrast material. Image analysis, which included three-dimensional reconstruction with virtual epicardial views, revealed the presence of a common trunk of the right and left inferior PVs. Figure 1 shows an axial view of the branching pattern of the common trunk (CIPV) into left and right inferior PVs. Figure 2 shows three-dimensional reconstructed epicardial views from behind (panel A) and above (panel B). The common trunk measured 30 mm in the superoinferior direction and 24 mm in the septolateral direction. Right and left branches separated after 8 mm. Both left and right superior PVs were normal in shape and diameter. A right middle PV was present. Catheter ablation was performed by circumferential cooled-tip radiofrequency application, anatomically and electrophysiologically guided by a variable-loop (15–25 mm), 20-pole, Lasso catheter (Biosense Webster, Diamond Bar, CA, USA). Ablation resulted in electrical disconnection of the three main PVs. The small right middle PV was not targeted by ablation.