<prompt> Not a feature of atrial septal defect:Fixed S2 splitMid diastolic murmurEjection systolic murmurParadoxical pulse  <response>: Ans. d Paradoxical pulse. Ref OP Ghai 6th ed. 402; Nelson Paediatrics, 18th1883ATRIAL SEPTAL DEFECT ASD: This is a common cardiac anomaly that may be first encountered in the adult and occurs more frequently in females. Can be divided into 3 types:- Ostium primum atrial septal defect ASD- Ostium secundum ASD, the more common type.- Sinus venosus defect less common.- Coronary sinus atrial septal defect Its most common form is osteum secundum defect. The most common ostium secundum type atrial septal defect involves the fossa ovalis and is midseptal in location. This type of defect should not be confused with a patent foramen ovale. True atrial septal defects, that is, defects within the confines of the fossa ovalis. Child is usually asymptomatic. Physical signs include- Mild left precordial bulge,- Loud S1,- Wide and fixed S2 split, - Systolic ejection murmur due to increasing flow across RV outflow into pulmonary artery.- Short rumbling mid diastolic murmur proved increasing volume of blood across tricuspid V. Left atrial enlargement does not occur early in the disease. Right bundle branch block is common CXR:- The heart in ASD is sometimes displaced to left Bedford sign.- Ascending aorta and arch tend to appear smaller than normal, probably due to rotation of ascending aorta by enlarged RA-RV, causing saggital alignment of arch Small knuckle.- The central pulmonary arteries are enlarged and there is a variable degree of pulmonary plethora, depending on the size of shunt.- Septal lines Kerley B lines in a patient of ASD should always suggest an associated mitral valve abnormality ECD or Lutembacher syndrome. The great hilar dance sign characterizes ASD on fluoroscopy. The Goose-neck deformity is seen in ASD on cardioangiography.Hilar dance sign is seen on fluroscopyTreatment of Atrial septal defect: Most ostium secundum defects should be closed. Optimal time for closure is a debated issue, however 2-5 yrs age is considered ideal for surgery. A large percentage of isolated secundum defects are now closed using transluminal percutaneous devices especially in children who have attained 10 kg or more weight. For the child in whom device closure is not an option, repair can easily be done on cardiopulmonary bypass using a patch of pericardium, polytetrafluoroethylene Gore-Tex, or Dacron if primary closure is not feasible.Indications for surgery in ASD: For secundum atrial ventricular defects which contributes to approximately 70 of ASDs that fail to spontaneously close and primum AV defects which contributes to approximately 20 of ASDs, treatment is aimed at closing the defect if a LR shunt of 1.5:2 or more is present. Closure is performed during the first decade, even in absence of symptoms to avoid late-onset RVF, endocarditis, and paradoxical emboli. Without surgery, 50-60 of infants with complete AV canal defect die from CCF secondary to large L R shunting andor AV valve incompetency by 1 year of age. 