Diagnosis of RHD:
To assess the echocardiographic RHD prevalence (including clinical and subclinical cases), we used the 2012 World Heart Federation (WHF) criteria (the Doppler and the morphological criteria) for diagnosis (10). Only left-sided valves were examined for features of rheumatic heart disease; mild tricuspid regurgitation and pulmonary regurgitation were frequently noted but were not regarded as indicating rheumatic heart disease. For a definite diagnosis of rheumatic heart disease, these features had to be identified concordantly by each of the echocardiographers. According to the 2012 WHF criteria; subjects were classified into definite RHD, borderline (equivocal) RHD or non-RHD (normal). Children with a definite RHD were reported and referred to a specialized clinic in Suez Canal University Hospital for further follow-up and possible intervention.