Diagnostic Criteria in Cardiac Sarcoidosis

Inclusion Criteria: * patients with suspected CS due to the following presentations: 1. age \< 65 years and new higher degree AV block, causative coronary artery disease excluded 2. age \< 65 years and new ventricular tachycardia, causative coronary artery disease excluded 3. age \< 65 years and ventricular tachycardia, causative coronary artery disease excluded 4. extracardiac sarcoidosis and cardiac involvement suggested (palpitations, abnormal ECG, abnormal echocardiography) To diagnose CS one of the following diagnostic tools will be used: A) World Association of Sarcoidosis and Other Granulomatous Disorders (WASOG) B) Heart Rhythm Society expert consensus statement on the diagnosis and management of arrhythmias associated with cardiac sarcoidosis C) Japanese Society of Nuclear Cardiology (JSNC) Patients whit histological confirmation from myocardial tissue fullfil will be defined as proven CS. (Group 1) Patients with clinical and imaging findings highly suggesting CS, but without histological confirmation from myocardial biopsy will be defined as probable CS (Group 2) Patients who do not fullfil the criteria or exhibiting findings suggesting an alternative, more likely diagnosis, will be considered as unlikely CS (Group 3) Exclusion Criteria: * unable or unwilling to provide informed consent * patients who are pregnant or lactating * noncompliant patients refusing the recommended therapy * age \< 18 years