Abstract 18282: Association Between Cardiac Computed Tomography Perfusion Imaging and Electronatomic Mapping to Evaluate Left Atrial Fibrosis in Patients with Atrial Fibrillation

Background: Prior studies have shown that contrast enhanced multislice computed tomography (ceMSCT) can visualize ventricular scar. The purpose of this manuscript is to assess the ability of ceMDCT to detect left atrial (LA) fibrosis in patients undergoing repeat ablation for atrial fibrillation (AF). Methods and Results: We enrolled 10 patients prior to repeat ablation. All patients underwent pre-procedural ceMSCT of the LA followed by voltage mapping of the LA during the ablation procedure. The ceMSCT images were processed off-line using Seg3D software (University of Utah, Salt Lake City, USA). Epicardial and endocardial contours were manually drawn around LA myocardium on multi-planar axial images. Electroanatomic mapping points were retrospectively registered to the corresponding ceMSCT images. LA Scar identified by an image intensity range between 0-30 Hounsfeld units (HU) on ceMSCT correlated qualitatively with scar identified by low-voltage (bipolar voltage <0.1 mV). Qualitative agreement in the posterior wall and the left pulmonary vein antrum was excellent. In a linear regression model of a subset of 4 patients, the local CT image intensity was associated with local bipolar voltage (+0.1 mV +/- 0.06 / 100 HU,P=0.019) Conclutions: We demonstrate that ceMSCT can provide valuable information about LA myocardial fibrosis with excellent electro-anatomic concordance. Electroanatomic voltage map of a redo PVI patient showing LA fibrosis in red corresponding to Low voltage (<0.1 mV). Figure 1-B. Contrast enhanced multislice computed tomography imaging derived scar map of the same patient showing the same projection of the left atrium. Image intensity of LA between 0 to 30 is shown in red and blood pool of left atrium is shown in light blue.