الفهرس 
Development and structure of the atrial septumOnly 14 pages are availabe for public view
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Abstract
Atrial septal defect ( ASD ) is a form of congenital heart defects that enables blood flow between two compartments of the heart called the left and the right atria .The ostium secundum ASD is the most common type of ASD and comprises ( 6 -10 % ) of all congenital heart diseases.A pulmonary to systemic flow ratio ( Qp / Qs ) 1.5 : 1 in stable patients without contraindications for surgery is widely indicated for repair . Smaller ASD ( pulmonary to systemic shunt flow ratios 1.5 : 1) is referred for closure in setting of the paradoxical embolization or right ventricular ( RV ) volume overload evidence . It is reasonable to close asymptomatic ASD with dilated RV evidence to reduce the risk of atrial arrhythmias . Closure is contraindicated in pulmonary vascular resistance 7 - 8 Woods units.