The condition is called ventricular septal defect. What happens is that when the left ventricle is contracting in systole a bit of the oxygenated blood gets back into the right ventricle. The implication is that the heart is under a overload. On the other hand, in diastole when the left ventricle is relaxing to receive the oxygenated blood from the lungs, some venous blood may leak into the left ventricle reducing the oxygen level. Obviously, the extent of the problem depends on the size of the hole. That you know about it indicates that some diagnosis was done. If the problem warranted it, the investigator will have suggested a fairly simple procedure called VSD Closure. A piece of Dacron or expanded PTFE patch is stitched over the hole. That completely solves the problem. This usually calls for an open heart surgery. However, there are some devices now available, which allow the hole to be closed from outside without an open heart procedure. Only a competent cardiologist can give proper advice.