An early diagnosis of cardiac sarcoidosis is important, particularly when considering the need for administering corticosteroid therapy. However, no reports are available on the success rate of diagnosis on the basis of biopsy findings in patients with cardiac sarcoidosis. This study investigated the diagnostic success rate of histologic evaluation of endomyocardial biopsy specimens in patients with this disease.Right ventricular endomyocardial biopsy was performed in 26 patients in whom cardiac sarcoidosis was strongly suspected according to the Diagnostic Criteria of Sarcoidosis, plus abnormalities on the electrocardiogram, cardiac radionuclide images, or in left ventricular wall motion. A mean of 4.0 sites were sampled per patient. In each case we determined whether a definitive diagnosis of cardiac sarcoidosis could be made histologically. Noncaseating granulomas were found in only 5 (19.2%) of the 26 cases, thus permitting a histologic diagnosis of cardiac sarcoidosis. A histologic diagnosis was made in 4 (36.4%) of 11 patients who exhibited a dilated cardiomyopathy-like clinical picture, in contrast to only 1 (6.7%) of 15 patients in whom conduction disturbances were the major clinical feature and whose left ventricular ejection fraction was within normal limits.The diagnostic rate achieved with biopsy in cardiac sarcoidosis is low; the patients with sarcoidosis and evidence of significant cardiac involvement should be treated for cardiac sarcoidosis despite negative myocardial biopsies for this disease.
