IJCS | Volume 33, Nº4, July and August 2020

391 Table 1 – Heart Rhythm Society diagnostic criteria for cardiac sarcoidosis Histologic diagnosis from myocardial tissue Noncaseating granuloma on endomyocardial biopsy with no alternative cause identified Clinical diagnosis Probable diagnosis of cardia sarcoidosis exists if there is histologic diagnosis of extra-cardiac sarcoidosis and one or more of the following is present: Cardiomyopathy or atrioventricular block responsive to immunosuppressive treatment Unexplained reduced LVEF (<40%) Unexplained ventricular tachycardia Mobitz II second- or third-degree heart block Patchy 18 F-FDG uptake on cardiac PET consistent with cardiac sarcoidosis Late gadolinium enhancement on cardiac MRI consistent with cardiac sarcoidosis Cardiac gallium-67 uptake and Exclusion of other causes of cardiac manifestations LVEF: left ventricular ejection fraction; PET: positron emission tomography; MRI: magnetic resonance imaging. Adapted from Blankstein et al. 58 Table 2 – 2017 Revised Japanese criteria for cardiac sarcoidosis 1. Major criteria 1. (a) High-grade atrioventricular block (including complete atrioventricular block) or fatal ventricular arrhythmia (e.g., sustained ventricular tachycardia and ventricular fibrillation) 2. (b) Basal thinning of the ventricular septum or abnormal ventricular wall anatomy (ventricular aneurysm, thinning of the middle or upper ventricular septum, regional ventricular wall thickening) 3. (c) Left ventricular contractile dysfunction (left ventricular ejection fraction less than 50%) 4. (d) Gallium-67 citrate scintigraphy or 18 F-FDG PET reveals abnormally high tracer accumulation in the heart 5. (e) Gadolinium-enhanced MRI reveals delayed contrast enhancement of the myocardium 2. Minor criteria 6. (f)  Abnormal ECG findings: Ventricular arrhythmias (nonsustained ventricular tachycardia, multifocal or frequent premature ventricular contractions), bundle branch block, axis deviation, or abnormal Q waves 7. (g)  Perfusion defects on myocardial perfusion scintigraphy (SPECT) 8. (h)  Endomyocardial biopsy: monocyte infiltration and moderate or severe myocardial interstitial fibrosis PET: positron emission tomography; MRI: magnetic cardiac imaging; ECG: electrocardiogram; SPECT: single-photon emission computed tomography Adapted from Terasaki F, Yoshinaga K. New guidelines for diagnosis of cardiac sarcoidosis in Japan. Ann Nucl Cardiol. 2017; 3(1):42-45. can lead to a perfusion defect. Usually, those defects do not follow the typical vascular distribution of coronary disease, unless when very extensive. Another finding described in some rest-stress perfusion studies is the reverse distribution. 30,31 It happens when a perfusion defect at rest improves on stress imaging and it is probably related to a focal reversible microvascular constriction in coronary arterioles around granulomas, however not specific to CS. SPECT imaging can be used together with 18F-FDG PET to evaluate the presence of active inflammation and its relation with scar. Despite being less sensitive than 18F-FDG PET and exposing the patient to a higher amount of radiation, gallium-67 scintigraphy using both planar imaging and SPECT is still used in CS, especially in areas with limited access to PET equipment. Gallium-67 citrate is produced in a cyclotron and has the advantage of being more available as its longer half-life can Wiefels et al. 18F-FDG PET/CT and cardiac sarcoidosis Int J Cardiovasc Sci. 2020; 33(4):389-400 Review Article