Electron microscopic findings of human auricular appendages.

Abstract

Auricular appendages were obtained from 20 patients ranging in age from 4 to 64 years with chronic heart diseases at the time of operation and observed with an electron microscope. Myo-endocardial fibrosis was seen in the majority of cases. Proliferation of smooth muscle cells was noticed in the areas of thickened myo-endocardial spaces. These smooth muscle cells played an important role in the production of ground substance, collagen, and elastic fibers in the fibrotic lesions.