What is A heart murmur is noted during the preschool physical examination of a 4-year-old girl. An echocardiogram reveals a defect between the right and left atrium involving the limbus of the foramen ovale. What is the most likely diagnosis? and explain in detail?
Ostium secundum-type ASD accounts for 90% of all ASDs. It reflects a true deficiency of the atrial septum and should not be confused with patent foramen ovale. Ostium secundum defects commonly occur in the middle portion of the septum and vary in size from a trivial opening to a large defect of the entire fossa ovalis. A small ASD is unlikely to be functional, but left-to-right shunting may occur in large defects, causing dilation and hypertrophy of the right atrium and ventricle. The ostium primum anomaly occurs adjacent to the AV valves and is usually associated with a cleft anterior mitral leaflet. Ventricular septal defect (choice E) occurs in the interventricular septum. The diagnoses in choices C and D are characterized by multiple congenital abnormalities and early cyanosis.Diagnosis: Atrial septal defect