Isolated cardiac sarcoidosis diagnosed by electroanatomic voltage mapping-guided endomyocardial biopsy combined with magnetic resonance imaging and positron emission tomography.

Cardiac involvement in sarcoidosis is related to lethal arrhythmias and is considered a serious condition. Because steroid therapy is an effective treatment, early diagnosis of cardiac sarcoidosis (CS) is of paramount importance in respect to improving prognosis. However, the diagnostic yield of histologic examination by endomyocardial biopsy (EMB) in CS is usually low. We report the case of isolated CS histopathologically proven by electroanatomical voltage mapping (EVM)-guided EMB combined with cardiac magnetic resonance imaging (CMR) and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET). A 53-year-old man presented with general fatigue. Electrocardiography showed intermittent complete atrioventricular block and echocardiography showed reduced cardiac function. CMR showed late gadolinium enhancement (LGE) in the areas of myocardium with suspected sarcoidosis. Next, we performed an EVM-guided EMB and found a non-caseating epithelioid granuloma in the right ventricular septum, which showed low voltage on EVM and LGE on CMR. FDG-PET showed accumulation in the same cardiac region. This case shows that EVM-guided EMB combined with diagnostic imaging can be a valuable approach in cases of suspected isolated CS. <Learning objective: To reduce inflammation and prevent ventricular remodeling by early corticosteroid treatment, detecting cardiac sarcoidosis (CS)-affected regions is important. Cardiac magnetic resonance imaging and positron emission tomography help detect such regions. However, histopathological diagnosis of CS by endomyocardial biopsy (EMB) is usually difficult. The present case suggests that electroanatomical voltage mapping-guided EMB combined with diagnostic imaging improves detection of CS-affected regions.>.