Normal, or innocent, murmurs can be heard in up to 77% of
infants. However, approximately 1% of
all babies born has something structurally wrong with the heart, otherwise known as a congenital heart defect. Furthermore, I am guessing that when you say that they think that his heart appears “round”, they are making this finding on interpretation of a chest radiograph, or chest X-ray. Unfortunately, these are not the most exact tools for diagnosis.