Carditis associated with mycoplasma pneumoniae infection.

Among 560 patients with serologically confirmed Mycoplasma pneumoniae infection, 25 (4.5%) had carditis (19 perimyocarditis, 6 pericarditis). During the acute phase 9 patients required intensive care. After an average of 16 months follow-up 11 patients with no previous signs of heart disease still had cardiac symptoms or signs. Thus carditis associated with M. pneumoniae infection is a serious disease, having cardiac sequelae more often than has hitherto been supposed. The pathogenesis of the carditis associated with M. pneumoniae infection is discussed, including the possibility that in some cases the elevated titre in the complement fixation test is non-specific. A summary is given of the 33 cases previously presented in the literature.