Elevated (18)F-fluorodeoxyglucose uptake in the interventricular septum is associated with atrioventricular block in patients with suspected cardiac involvement sarcoidosis.

PURPOSE: Cardiac involvement in sarcoidosis is one of the leading causes of death associated with abnormalities of the conduction system. (18)F-FDG PET is useful for detecting inflammatory lesions in cardiac sarcoidosis. However, the relationship between ECG abnormalities and focal (18)F-FDG uptake has not been studied. The aim of this study was to evaluate the relationship between electrocardiogram (ECG) abnormalities and the location of elevated myocardial (18)F-FDG uptake in patients with sarcoidosis.

METHODS: Included in the study were 50 patients (56.3 ± 14.9 years old) with histologically proven sarcoidosis with suspected cardiac involvement based on ECG or echocardiography. All patients had fasted for at least 6 h and were given unfractionated heparin (50 IU/kg) intravenously to reduce the physiological (18)F-FDG uptake in the myocardium. The left ventricle (LV) wall was divided into 17 segments by visual analysis. Obvious accumulation in each segment was defined as positive.

RESULTS: Of the 50 patients, 33 showed some ECG abnormalities, including atrioventricular (AV) block in 13. Patients with abnormal ECG findings had a higher number of regions with (18)F-FDG uptake than patients without ECG abnormality (3.48 ± 2.73 vs. 1.41 ± 2.09 regions, p = 0.0051). Among ECG abnormalities, the predictor for interventricular septum wall (18)F-FDG involvement was AV block (p = 0.0025).

CONCLUSION: Patients with ECG abnormalities showed a higher number of abnormal (18)F-FDG myocardial uptake regions than patients without ECG abnormalities. In particular, focal (18)F-FDG uptake in the interventricular septum in cardiac sarcoidosis was associated with AV block. Therefore, determination of regional (18)F-FDG distribution might contribute to patient management in cardiac sarcoidosis.