hey there, i think its most likely, Ventricular Septal Defect. It is by far one of the most common congenital heart conditions affecting young kids. And yes as ankigarg87 mentioned, it is a defect between the left ventricles and right ventricles, allowing blood to flow from the left ventricle to the right ventricle. Usually, your child won't present with symptoms at birth until a few weeks after that.
Fortunately most VSDs are small and close up by itself. There are some large VSDs that will need surgical repair otherwise later on in life, it will cause heart and lung problems.