Prevalence of atrial FDG uptake and association with atrial arrhythmias in patients with cardiac sarcoidosis

Background: There is increasing evidence that a proportion of patients with cardiac sarcoidosis (CS) have atrial arrhythmias (AA). Although 18F-fluorodeoxy-glucose (FDG) uptake in the ventricle on positron emission tomography/computed tomography (PET/CT) is well studied, FDG uptake in the atrium has not been elucidated in detail.

Objectives: To evaluate FDG uptake in the atrium and its relationship with AA in patients with CS.

Methods: We retrospectively investigated 62 CS patients. All patients underwent echocardiography and PET/CT. Serum angiotensin converting enzyme (ACE) and soluble IL-2 receptor (sIL-2R) levels, plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) concentrations were also evaluated. ECG, Holter monitoring and device interrogations were used to detect AA.

Results: Of the studied population, 25 patients (40.3%) had AA, of which 2 patients had atrial tachycardia (AT) and 23 patients had atrial fibrillation (AF). Eighteen patients with AA had atrial FDG uptake on PET/CT, whereas 14 patients without AA had atrial FDG uptake (72.0% vs 37.8%, P = 0.017). Multivariate analysis revealed a significant association between AA and age (odds ratio [OR]: 1.15; 95% confidence interval [CI]: 1.01-1.31, P = 0.040), atrial FDG uptake (odds ratio [OR]: 7.23; 95% confidence interval [CI]: 1.91-27.36, P = 0.004), and left atrial diameter (OR: 1.08; 95% CI: 1.01-1.16, P = 0.027). Meanwhile, gender, serum ACE and BNP levels, and left ventricular ejection fraction were not associated with AA.

Conclusions: Atrial FDG uptake was common in patients with CS and strongly associated with AA.