First of all a heart murmur is simply an extra sound that the doctor hears when he listens to the chest with his stethoscope. Most heart murmurs are innocent sounds and mean absolutely nothing. Occasionally, (about 1 out of 1000) a heart murmur can be because there is a valve in the heart that is either leaking or stiff or there can be a heart murmur because there is a hole between the heart chambers that isn t supposed to be there. For a two year old the easiest way to find out if this is an innocent murmur or not is to have a test called an echocardiogram. An echocardiogram is simply an ultrasound of the heart. It is a harmless pain free test that enables one to visualize all the heart valves, heart chambers, heart muscle and measure the blood flow through the heart chambers and valves. It can take anywhere from a half hour to one hour to perform. Occasionally two year olds have a hard time sitting still for the test so sedation may be a possibility. It is important to have the echocardiogram done at a lab that does a lot of kids as they have the experience to rule out congenital heart defects plus they would be used to imaging and dealing with scared children. Again, most murmurs, 99%, are innocent and do not mean there is a heart problem. If your child has normal exercise tolerance, is growing and gaining weight normally and has never been blue the odds are high that the murmur is innocent or if there is a problem it is most likely a minor one and unlikely that it would be a serious life threatening one. Hope that helps.