“…Even acute pericarditis may be undetected (Graef et al, 1949). These findings have been supported by the low incidence of clinically detectable pericarditis in patients with rheumatoid disease (Rogen, 1947;Fischmann and Gwynne, 1948;Rosenberg et al, 1950;Egelius et al, 1955;Cathcart and Spodick, 1962;Lebowitz, 1963). Acute rheumatoid pericarditis is not commonly reported in adults; Cathcart and Spodick (1962) describe 5 in a series of 254 patients with rheumatoid arthritis, while in most clinical series no examples of pericarditis occur.…”