Pathology of the Cardiac Conduction System in Systemic Lupus Erythematosus

Abstract

Pathology of the cardiac conduction system was studied at necropsy in 8 patients with systemic lupus erythematosus (SLE) who had developed arrhythmias or conduction disturbances shortly before dying. Histologic abnormalities observed in the sinus node included focal degeneration and fibrosis secondary to occlusive lesions of small nodal arteries, periarteritis about the relatively large central artery of the sinus node, nodal inflammation from pericarditis, endocardial thrombi beneath the node, and a cystic degeneration of the collagen framework of the sinus node. The AV node generally was less damaged but also showed focal degeneration secondary to small arterial pathology and was additionally the site of inflammation at the interface between node and central fibrous body. Disturbances in cardiac rhythm and conduction occurring in patients with SLE have thus been found to be associated with structural damage in the cardiac conduction system.