An autopsy case of rheumatoid arthritis with an involvement of the cardiac conduction system.

A case of rheumatoid arthritis with an involvement of the cardiac conduction system was described. The patient was a 65-year-old man who had a 15-year history of classical rheumatoid arthritis combined with an advanced atrioventricular (AV) block resulting in Adams-Stokes seizure. Prior to the occurrence of the AV block, a complete right bundle branch block with a left axis deviation and a first-degree AV block were found on an electrocardiogram (ECG). The histological examination of the conduction system according to the serial sectioning method disclosed that the branching portion of the His bundle and anterior fascicle of the left bundle branch were replaced by the scarring tissue and that the penetrating portion of the His bundle, the AV node and the right bundle branch had rheumatoid granulomatous lesions. The extent and localization of the lesions in the conduction system were well correlated with the findings on the ECG.