My son's pediatrician heard a "loud second heartbeat" during his wellness checkup. any idea what this problem is?

Talk to your pedi: If your pediatrician noted an abnormality on your child's physical exam, they should discuss this with you. Please ask them for a clarification. In general if heart sounds are noted that a doctor feels is concerning and abnormal, an echocardiogram may be done to further evaluate.

Heart Sounds: Heart sounds refer to the respective valves closing in your heart. A loud or extra heart sound should be evaluated by a cardiologist after a discussion with your physician.