Study design and sampling:
Suez Canal region representing the eastern section of Egypt was our
study area. A cluster random sample was used to ensure full
representation of all population varieties of the region. The region was
divided into rural and urban areas and then in each area the schools
were divided into primary, preparatory and secondary schools. A cluster
random samples was chosen from the studied region then a random number
of students were included.
Approval of the survey by the ethics committee of the Ministry of Health
and Education Ministry of the selected regions were obtained. After
obtaining an informed consent from parents or guardians, children at
school age (6-18 years) were included in the study as follows:
The region under study was classified into rural and urban areas. All
schools in the chosen area were enumerated and classified into either
primary, preparatory or secondary. The sample size was distributed
proportionally on the three stages according to gender distribution
(Table 1). Schools in each stage were chosen on random basis by using
computer software (Epi-Info 3.4.3) and the selected schools were visited
by the study group.
A total of 1680 students were screened, 119 echocardiographic studies
were non-interpretable; so, a total of 1560 studies were evaluated.
Each student from the chosen sample was subjected to 1) Medical history
(including demographic data, pervious history of rheumatic fever and any
current symptoms) through a verbally administered questionnaire. 2)
Detailed cardiac examination and detected murmurs were reported and
correlated with echocardiographic findings. 3) A transthoracic
Echocardiographic assessment by portable echo machine (Esoate MyLab30)
were performed on site by well-trained experts in the standard views.
We developed an abbreviated echocardiographic protocol that took 5–10
min per child and focused on rheumatic pathology of the mitral and
aortic valves from the parasternal long axis, apical four and five
chamber views, with particular attention being paid to valve morphology
on two-dimensional imaging and the degree and extent of mitral and
aortic regurgitation, assessed by color flow Doppler imaging.
Transvalvular flow was assessed by measuring the peak velocity with
continuous wave Doppler imaging. Echocardiographic data was stored on
the device to be revised in the echo lab by two separate experts blinded
to the clinical data.