De Subitaneis Mortibus
VIII. Coronary Arteries and Conduction System in Scleroderma Heart Disease
In eight cases of scleroderma heart disease studied at necropsy special attention was paid to the cardiac conduction system and the coronary arteries. Six of the eight patients died suddenly, and all had some form of electrical instability of the heart. Distinct morphological abnormalities were present in the sinus node, atrioventricular (A-V) node and His bundle of every case, with sclerotic destruction of the sinus node being particularly striking in four of the hearts. Widespread lesions of the small coronary arteries (less than 1 mm diameter) were present in the ventricular myocardium, the sinus node artery and the A-V node artery. These lesions included mural and intimal fibrosis, endothelial proliferation, medial hyperplasia, fibrinoid necrosis and platelet-fibrin clots. The large coronary arteries were conspicuously normal or minimally diseased except in one case, and in that example there was no myocardial disease attributable to the single large coronary lesion found. It is concluded that arrhythmias and conduction disturbances are an integral component of the clinical picture of scleroderma heart disease, that this is associated with structural abnormalities in the centers of impulse formation and conduction, and that widespread narrowing lesions of the small coronary arteries (but not the major trunks) are important as a basis for fibrotic and degenerative changes throughout the heart. Some components of the fibrosis, particularly in the sinus node, seem disproportionate and suggest that both microvascular and primary collagen abnormalities contribute to the pathogenesis of scleroderma heart disease.
- © 1974 American Heart Association, Inc.