Scanning electron microscope features of rheumatic vegetations in acute rheumatic carditis.

We have studied four cases of acute rheumatic carditis at autopsy in which the cardiac valves revealed rheumatic vegetations. The features of these vegetations were investigated by scanning electron microscopy. There was a loss of the normal mosaic arrangement of endothelial cells and marked architectural modifications of the valvar collagen. These features explain well the pathologic processes of rheumatic valvitis and the infective complications, if any, thereof. To the best of our knowledge, this is the first time that an analysis has been made of the structure of the surface of rheumatic vegetations.