Quantitation of mast cells in 100 normal and 92 diseased human hearts. Implications for interpretation of endomyocardial biopsy specimens.

In endomyocardial specimens from 100 normal hearts from autopsy, the mean number of mast cells per high-power field was calculated. A peak occurred in the third decade and was more marked in women than men. In the fourth through seventh decades, mean values were greater in men than women. For both sexes, the number of mast cells in the left ventricle tended to exceed that in the right ventricle. The number of mast cells was similarly determined in 92 diseased hearts. The range of mean values overlapped considerably with that of normal hearts. The highest mean values occurred in subjects with mast cell neoplasia, giant cell myocarditis, and lymphocytic myocarditis; and the lowest occurred in the group with amyloidosis. The values in patients with eosinophilic myocarditis did not differ appreciably from normal. Increased numbers of mast cells tended to be associated with areas of fibrosis more than with inflammatory infiltrates.