Utility of CT and MRI in Cardiac Electrophysiology

Cardiac electrophysiology involves the diagnosis and management of arrhythmias. CT and MRI play an increasingly important role in cardiac electrophysiology, primarily in preprocedural planning of ablation procedures but also in procedural guidance and postprocedural follow-up. The most common applications include ablation for atrial fibrillation (AF), ablation for ventricular tachycardia (VT), and for planning cardiac resynchronization therapy (CRT). For AF ablation, preprocedural evaluation includes anatomic evaluation and planning using CT or MRI as well as evaluation for left atrial fibrosis using MRI, a marker of poor outcomes following ablation. Procedural guidance during AF ablation is achieved by fusing anatomic data from CT or MRI with electroanatomic mapping to guide the procedure. Postprocedural imaging with CT following AF ablation is commonly used to evaluate for complications such as pulmonary vein stenosis and atrioesophageal fistula. For VT ablation, both MRI and CT are used to identify scar, representing the arrhythmogenic substrate targeted for ablation, and to plan the optimal approach for ablation. CT or MR images may be fused with electroanatomic maps for intraprocedural guidance during VT ablation and may also be used to assess for complications following ablation. Finally, functional information from MRI may be used to identify patients who may benefit from CRT, and cardiac vein mapping with CT or MRI may assist in planning access.