الفهرس 
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Abstract
INTRODUCTION
Congenital heart diseases are the most common congenital anurrmlies in children and infants.
The incidence is about 0.8% of live births (Fridman. 1995).
Hickey et a!. in ( 191!5! described cnuothelin as enuotensin or endothelial contracting
factor. It was described as a naturally occurring polypeptide substance produced by vascular
endothelial cells and has a potent vasoconstrictor and mitogenic activity on vascular
smooth muscle cells (Mathias eta/., 1995).
Endothelin is considered as a disease marker or an etiologic factor in pulmonary hypertension,
systemic hypertension, congestive heart failure. myocardial and vascular wall
hypertrophy, ischemic heart disease and atherosclerosis ( Praveen,
1995).
Yoshibarashi et a/. in (1991) discovered that endothelin may be involved in pathophysiology
of pulmonary hypertension.
Also. Vincent et a/. I1993) suggested that the increase in pulmonary blood !low may be
a stimulatory factor in production andlor release of endothelin in children with
congenital heart defects.
This was also reported by Ishikawa eta/. in (1995) who studied patients with left to
right shunt. They found signiticantly higher levels of endothelin in their patients when
compared to control subjects.
AIM OF THE WORK:
The aim of this work is to study the role of endothelin in the contribution in the haemodynamics
disturbances and abnormal blood tlow in patients \Vith congenital heart disease.
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