Experimental allergic serous rabbit endocarditis and cardiav valvular lesions in rheumatoid arthritis. --A comparative study.

Fibrosis of the chordae tendinae pathogenetically comparable to the rheumatoid arthritis (RA) conditioned alterations in the chordae tendineae was to be induced experimentally using the model of allergic-hyperergic rabbit endocarditis. 2. Furthermore, 45 hearts of RA autopsy cases were compared with 200 control heart. All heart valves and chordae tendineae were examined for occurence of diffuse fibroses, adhesions and rufflings as well as for ulcerations and thrombi. The degree of the pathological changes was classified in ""slight'', ""mean'', and ""severe'' (see table 1). 3. The tissue lesion can either lead to endothelial injury resulting in verruciform endocarditis or it can change over from recurrent edema with subsequent edematous sclerosis to etiologically ambiguous nonspecific fibrosis. 4. The persistent allergic-hypergic irritation in rabbit endocarditis likewise caused fibrosis of the chordae tendineae. During the progress of the disease the lesions are ranging from acute edema over edematous sclerosis to fibrosis. In the relatively short experimental period adhesions of the chordae tendineae and sheat-like depositon of newly formed connective tissue as common in allergic processes in RA were not observed. The pathogenetic reactions due to experimental endocarditis were comparable with those in RA.