QT Dispersion predicting acute rheumatic carditis.

OBJECTIVE

To investigate QT dispersion in the surface electrocardiogram of children with rheumatic carditis.

METHODS

QT dispersion was quantitatively evaluated in 33 children with acute rheumatic carditis. As a control group, we studied 33 healthy children free of any disease. The children were eligible for participation if the following criteria were met: diagnosis of acute rheumatic fever based on the revised Jone's criteria and suffering from their first attack of carditis. The echo Doppler cardiogram was performed in all children, within 48-72 hours of hospitalisation.

RESULTS

Patients with carditis had a greater QT dispersion than the control group. When we analyse the QT dispersion according to the severity of the carditis, we observed that the dispersion tended to be greater in those with more severe valvar lesion. The sensitivity and specificity of the measurements of the QT dispersion in predicting acute carditis were estimated by using receiver operating characteristic curves. A QT dispersion greater than 40 milliseconds had a sensitivity of 63.6% and a specificity of 93.9% in predicting acute rheumatic carditis.

CONCLUSION

The lengthening of QT dispersion may reflect on cardiac involvement in rheumatic fever and be a new important parameter in the diagnosis and therapeutic decision for rheumatic carditis.