Atrial septal defect is a hole in the upper chambers of the heart. Definitely this hole needs to be closed as ASDs do not close spontaneously at this age. Surgery is by far and large the safest, surest and the cheapest method of treatment of ASD. However ASD can also be closed percutaneously by putting certain devices called umbrella devices. However this is a technical decision and only when we see the patient and critically evaluate the hole on echocardiography, can be comment whether device closure is feasible in his case or not. There is nothing like microsurgery. However, various surgical procedures are available in which chest need not be opened fully and this operation can be performed using relatively small incision and that is what is called minimally invasive surgery and not microsurgery. It is best to close the defect in the preschool age group that is the age of 3-5 years as it has certain harmful effects if left untreated for a long period of time. The pressures of the lungs start going up as also irregular rhythms of the heart can develop and whenever surgery is performed late there may be incomplete resolution of the pressures of the lung and increased size of the heart. It is therefore always advisable to do this surgery early rather than late. However if you wish to wait for 4-6 months for some reasons then I suppose it should be reasonably safe to wait. But in case you want to wait hoping that hole will close, then be rest assured this hole will never close spontaneously and will have to be closed either surgically or by percutaneous devices as mentioned earlier. I hope I have answered your queries to your satisfaction. However, if there are any further doubts, please feel free to contact us and it shall be our pleasure to answer them.