Cardiac lesions do occur in rheumatoid arthritis and are noted more frequently at necropsy than on clinical examination and study. There is evidence that a specific form of heart disease may be present. The rheumatoid granuloma, which histologically is similar to the subcutaneous nodule, may be found in any portion of the heart. At necropsy, nonspecific changes consisting of focal infiltrations may also be found. While seldom noted clinically, pericarditis also is frequently noted at necropsy.
Schwartz S. Rheumatoid Carditis. JAMA. 1967;201(7):556-558. doi:10.1001/jama.1967.03130070076029