Multi–Detector Row CT of the Left Atrium and Pulmonary Veins before Radio-frequency Catheter Ablation for Atrial Fibrillation

Radio-frequency catheter ablation (RFCA) of the distal pulmonary veins and posterior left atrium is increasingly being used to treat recurrent or refractory atrial fibrillation that resists pharmacologic therapy or cardioversion. Successful RFCA of atrial fibrillation requires resolution of abnormal rhythms while minimizing complications and can be achieved with precise, preprocedural, three-dimensional (3D) anatomic delineation of the target, the atriopulmonary venous junction. Three-dimensional multi-detector row computed tomography (CT) of the pulmonary veins and left atrium provides the necessary anatomic information for successful RFCA, including (a) the number, location, and angulation of pulmonary veins and their ostial branches unobscured by adjacent cardiac and vascular anatomy, and (b) left atrial volume. The 3D multi-detector row CT scanning and postprocessing techniques used for pre-RFCA planning are straightforward. Radiologists must not only understand these techniques but must also be familiar with atrial fibrillation and the technical considerations and complications associated with RFCA of this condition. In addition, radiologists must be familiar with anatomic variants of the left atrium and distal pulmonary veins and understand the importance of these variants to the referring cardiac interventional electrophysiologist.