Anomalous midline common ostium of the left and right inferior pulmonary veins: implications for pulmonary vein isolation in atrial fibrillation.

A 41-year-old man with a history of paroxysmal symptomatic atrial fibrillation refractory to antiarrhythmic drug therapy was referred for pulmonary vein (PV) isolation. Before the procedure, he underwent standard cardiac computed tomographic angiography to evaluate left atrium and PV anatomy, which revealed single right and left superior PVs, each with a moderate-sized ostium. However, the right and left inferior PVs originated from a common and unusually large ostium in the midpostero-inferior left atrium (Figure). Using a double trans-septal approach, an 8-mm tip deflectable ablation catheter and a 20-pole LASSO catheter were inserted …