High take-off left inferior pulmonary vein as an obstacle in creating a conduction block at the lateral mitral isthmus.

AIMS: Creation of complete linear lesions in the lateral mitral isthmus (LMI) by catheter ablation for treating atrial fibrillation remains technically challenging. We aimed to clarify whether a high take-off left inferior pulmonary vein (LIPV) can hamper the creation of a complete block at the LMI. METHODS AND RESULTS: We included 81 consecutive patients who underwent linear ablation at the LMI and cardiac computed tomography (CT) before ablation. We defined a high take-off LIPV when the level of the lower edge of the LIPV ostium was higher than that of the top of mitral annulus on CT. The clinical backgrounds, parameters, and long-term follow-up were then compared between the success (successful creation of a complete LMI block) and failure groups. A complete LMI block was obtained in 60/81 (76%) patients. In the failure group, a high take-off LIPV was noted more commonly and the LMI tended to be longer than the success group. Multivariate analysis revealed that a high take-off LIPV was an independent predictor of failure to achieve a complete LMI block. The sinus rhythm maintenance rate was not different between the success and failure groups. CONCLUSION: A high take-off LIPV hampered the creation of complete linear lesions in the LMI.