Dear Smilepraveen,
Your child has a hole between the upper two chambers of the heart called an atrial septal defect, or ASD. The 1.5:1 shunt means that there is some increased blood flow returning to the lungs. However, patients with ASDs are typically asymptomatic and are able to grow adequately. Without seeing your child, I do not know how large the defect is. There may be a reasonable chance that the defect may get smaller over time. It does not have to close completely--it only has to become small enough to restrict the amount of blood that is returning across the defect from the left side of the heart to the right. If your child continues to have a sizable defect in which the right side of the heart remains enlarged by age 2-4 years, it will likely mean that the defect should undergo closure, either by surgery or by a device that is placed by a catheter in the heart. ASDs are not associated with sudden cardiac death, so your child should otherwise do well at this point.
Do you know the size of the defect? ASD (atrial septal defect)s will often close on their own. My daughter was born with a large VSD and small ASD. Her ASD is getting smaller on it's own, however she is having open heart surgery next month to repair her VSD.