An international consensus document (1) indicated that the diagnosis of cardiac sarcoidosis requires a cardiac biopsy showing non-caseating granuloma without alternative explanation or an extracardiac tissue biopsy showing non-caseating granuloma without alternative explanation plus one or more of the following without alternative explanation: Corticosteroid-responsive cardiomyopathy or heart block Unexplained reduced left ventricular ejection fraction < 40% Unexplained spontaneous or induced ventricular tachycardia Mobitz type II second-degree AV block or third-degree AV block Cardiac PET scan showing patchy uptake Cardiac MRI showing late gadolinium enhancement Positive gallium uptake on a nuclear scan Most commonly, the diagnosis is established by extracardiac biopsy in conjunction with suggestive cardiac abnormalities on noninvasive testing.