septal defect

a hole in the SEPTUM or partition between the left and right sides of the HEART , whether in the atria (see ATRIUM ) or VENTRICLES . This condition is a CONGENITAL disorder caused by an abnormal development of the foetal heart. Whether the defect is atrial or ventricular, it allows incorrect CIRCULATION OF THE BLOOD from left to right, from higher pressure to lower. This is called a shunt and results in too much blood flowing through the LUNGS . PULMONARY HYPERTENSION results, and a large shunt may cause heart failure. Surgery can correct the defect, although a small one may not require any treatment.