Atrioventricular conduction in children with acute rheumatic fever.

Atrioventricular conduction was quantitatively evaluated in 118 children with acute rheumatic fever. The mean PR index in children with acute rheumatic fever, 1.06 +/- 0.38, was significantly higher than normal children or children who had febrile illness of nonrheumatic or nonstreptococcal origin (P is less than .001). Among 35 children with rheumatic fever and an abnormal PR index, the disease presented as carditis in 21, arthritis in ten, and chorea in four. The mean PR index and the frequency distribution of abnormal PR indices were significantly higher in children with carditis (P is less than .001). Five children who initially had an abnormal PR index and arthritis or chorea subsequently developed carditis. These observations suggest that children with acute rheumatic fever and abnormal PR index warrant close observation for possible clinical evidence of myocardial involvement during subsequent course of the illness.