Histopathological differentiation employing endomyocardial biopsy in the clinical assessment of primary myocardial disease.

Abstract

By utilizing endomyocardial biopsy, the clinical diagnosis and clas-sification of primary myocardial disease is possible. This procedure will immediately eliminate the possibility of such secondary myocardial diseases as sarcoidosis, amyloidosis, glycogen storage disease and myocarditis.Histopathologic differentiation of primary myocardial disease was investigated by analyzing the pathologic and diagnostic significances of endocardial and myocardial lesions at probable sites of pathology of 126 autopsied or biopsied cases of different diseases and in numerous biopsy specimens from 173 cases of myocardial disease. At varying intervals following biopsy, 9 cases were autopsied. Biopsy and autopsy findings correlated well.The following histopathological findings were noteworthy.1. Endocardial thickening: This is a characteristic finding in endo-cardial fibroelastosis. Other endomyocardial diseases can be diagnosed when various causal genetic factors are excluded.2. Myocardial hypertrophy: Size of muscle fibers, fragmentation of myofibrils, vacuolization, pyknosis and pleomorphism of nuclei and derangement of muscle bundles should be noted.Interstitial fibrosis accompanies the advanced cases.3. Myocardial degeneration or fibrosis: Vacuolization, hydropic degeneration, swelling, pleomorphism, basophilic or mucoid degeneration and deposition of other abnormal substance are to be recorded. Artifacts should be disregarded.When attempting to establish a histopathologic biopsy diagnosis, such factors as inflammatory, toxic, thrombogenic, anoxic, hemodynamic, mechanical and metabolic conditions should be excluded as far as possible.It should be emphasized that an endomyocardial biopsy is one of the most important diagnostic means to determine the classification when combined with other diagnostic methods.Finally, we must reaffirm that the negative biopsy report does notdeny the presence of the disease.