Abstract 17970: Atrial Fibrillation is Associated With Increased Atrial Metabolic Activity on FDG/PET Imaging in Patients With Ischemic Cardiomyopathy

Abstract

Introduction: Atrial Fibrillation (AF) is a common arrhythmia but its pathogenesis remains incompletely understood. Alterations in metabolism may play a role. 18F-fluorodeoxyglucose (FDG) PET reflects glucose uptake in metabolically active tissue but studies evaluating the relationship between atrial FDG uptake and atrial fibrillation are limited. Hypothesis: We hypothesized that patients with ischemic cardiomyopathy who have had AF have increased atrial wall FDG uptake compared to patients without AF (no-AF). Methods: Atrial uptake was assessed visually and quantitatively on FDG-PET/CT images in 42 patients (24 AF, 18 no-AF). The maximum and mean FDG Standard Uptake Value (SUV) in the left atrium (LA), right atrium (RA) and mean blood pool activity were measured (see figure). The Tissue:Blood ratio (TBR) was calculated using the maximum atrial wall SUV (TBRmax) and mean SUV (TBRmean). Results: Median age was 72 years; (78% male). Mean LVEF was similar between AF vs. No-AF patients (24+/-10% vs. 26+/-11%, p=0.57). The RA was visualized in 88% of AF and 44% of no-AF patients (p=0.002). The LA was visualized in 88% of AF and 72% of no-AF patients (p=0.22). See table for TBR results. TBRmax and TBRmean were significantly increased in the RA wall of patients with AF vs. no-AF. There was a trend for increased FDG in the LA wall of AF patients. Conclusion: Among patients with ischemic cardiomyopathy, significantly greater FDG uptake was noted in the RA of patients with AF vs. No-AF (with a trend for LA uptake). These findings suggest increased glucose metabolism in the atria in patients with AF. Further study is warranted to determine the clinical and biological significance of these findings.