Risk of underdiagnoses of cardiac sarcoidosis by routine electrocardiogram and echocardiogram in patients with biopsy-proven extracardiac sarcoidosis

Abstract

Background: Heart Rhythm Society (HRS) consensus statement recommends that patients with biopsy-proven extracardiac sarcoidosis (extra-CS) should be screened for CS with an electrocardiogram (ECG) and echocardiogram (Echo). However, there have been lack of studies investigating prevalence of CS in patients with normal ECG and Echo. Aims and objectives: To investigate prevalence and explore characteristics among these patients. Methods: We studied 94 consecutive biopsy proven extra-CS patients. All patients underwent F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) and cardiac MRI for the evaluation of CS. Patients were categorized into 2 groups according to the ECG and Echo findings as normal or abnormal of either or both ECG or Echo. The Japanese Ministry of Health and Welfare (JMHW) criteria 2015 were used as the standard for the diagnosis of CS. Results: Among the 94 patients, 28 (30%) were normal and 66 (70%) were abnormal group. The prevalence of CS was as follows; 6/28 (21%) for normal, 39/66 (59%) for abnormal (p=0.0006). Of these 6 patients from normal group, FDG-PET and/or cardiac MRI showed that 1 patient had multiple organ involvement (lung, skin, stomach, bone and heart), 3 patients had cardiac involvement in the RV papillary muscle, inferior or lateral wall of the LV, 1 patient had small subendocardial lesions in the mid segments of the anteroseptal and inferior walls, and 1 had relatively lower LVEF for his age. Conclusions: The prevalence of CS exceeds 20% in extra-CS patients even with normal ECG and Echo. Physicians should keep in mind such an unrecognized population and risk of underdiagnosis of CS.