QT dispersion in acute rheumatic fever

Abstract

Disturbances of conduction are well known in the setting of acute rheumatic fever. The aim of this study is to investigate the QT dispersion as seen in the surface electrocardiogram of children with acute rheumatic fever. QT dispersion was quantitatively evaluated in 88 children with acute rheumatic fever. Patients were divided into two groups based on the absence or presence of carditis. As a control group, we studied 36 healthy children free of any disease, and matched for age with both groups. Repeat echocardiographic examinations were routinely scheduled in all patients at 3 months after the initial attack to study the evolution of valvar lesions. The mean QT dispersion was significantly higher in children with rheumatic carditis. But there was no statistical difference between children without carditis and normal children. Among the children with carditis, the mean dispersion was higher in those with significant valvar regurgitation. Dispersion of greater than 55 milliseconds had a sensitivity of 85%, and specificity of 70%, in predicting rheumatic carditis, while a value of 65 milliseconds or greater had sensitivity of 81% specificity of 85% in predicting severe valvar lesions in acute rheumatic carditis. At follow-up examination, a clear reduction on the QT dispersion was the main finding, reflecting an electrophysiological improvement. These observations suggest that QT dispersion is increased in association with cardiac involvement in children with acute rheumatic fever.