The use of serial cardiac 18F-fluorodeoxyglucose– positron emission tomography imaging to diagnose, monitor, and tailor treatment of cardiac sarcoidosis patients with arrhythmias: a case series and review

Abstract

Background Clinically evident cardiac involvement has been documented in 5% of sarcoidosis patients, primarily manifesting as heart block, ventricular arrhythmias, and heart failure. Heart Rhythm Society consensus guidelines recommend advanced cardiac imaging with fluorodeoxyglucose–positron emission tomography (FDG-PET) scan for diagnosis of cardiac sarcoidosis, given endomyocardial biopsy’s low sensitivity. Case summary We describe four patients with cardiac sarcoidosis diagnosed with FDG-PET scan performed using a standardized imaging protocol for cardiac sarcoidosis. Serial FDG-PET scans were performed to monitor disease progression and response to therapy. Patients 1 and 2 presented with heart block, Patient 3 with heart failure and ventricular tachycardia (VT), and Patient 4 with VT. Patient 1 showed an initial decrease in standard uptake value (SUV) on immunosuppression, followed by an increase in SUV, necessitating steroid therapy. Patient 2’s SUV decreased on immunosuppression. Patient 3 required 3.5 years of immunosuppression for the SUV to decrease to inactive disease levels, with SUV increasing and decreasing at different times during treatment, and subsequently developed VT. For Patient 4, areas of inflammation on the initial scan matched low voltage areas on the patient’s EP study, confirming the arrhythmia’s pathophysiological basis. Discussion Cardiac sarcoidosis progression and response to therapy are heterogeneous. Serial FDG-PET scans are useful to diagnose disease, tailor therapy, and monitor the clinical course of disease, allowing treatment decisions to be based on the quantitative level of inflammation seen on FDG-PET.

Ten Questions Cardiologists Should Be Able to Answer About Cardiac Sarcoidosis: Case-Based Approach and Contemporary Review

“…Repeat PET scan allows for assessment of treatment response and can help to adjust immunosuppression. 75,[84][85][86] One study also showed that a reduction in FDG uptake was associated with an increase in LVEF. 87 There are scarce data supporting the use of PET scan for risk stratification in patients with CS although one study showed a significant association between SUV count at the time of diagnosis and future cardiac events.…”

Sequential FDG-PET in the management of multiorgan sarcoidosis

“…FDG-PET can be used to guide both diagnosis and management of sarcoidosis, 1 2 and may be useful for assessing treatment response, disease extent, occult disease, 3 and may have utility in stratifying prognosis 4 and FDG-PET and cardiac MRI can be complementary, 5 but there is significant radiation exposure associated with repeated PET imaging. Follow-up FDG-PET after 6 months of therapy showed interval reduction in cardiac metabolic activity and improvement in the pulmonary and nodal disease (figures 1B and 2B).…”