Congenital abnormalities of the tricuspid valve are uncommon in children. On the other hand, some degree of tricuspid valve leakage (regurgitation) is commonly seen on echocardiograms done during childhood and usually is not pathologic. First thing you need to do is to ask your child's cardiologist if this is the "normal" type of tricuspid valve leakage or not. If the valve makes a distinctive sound, it make be a click, which would indicate a structural abnormality of the valve, the most common of which is called Ebstein's anomaly. In this situation, one or more of the tricuspid valve leaflets do not delaminate ("peel off") from the walls of the embryologic heart in the normal fashion. Some child have severe dysfunction of these valves and present in heart failure in infancy. On the other side of the spectrum, some people don't find out about it until adulthood, if the valve has been functioning well. Ask your child's cardiologist if they think she has Ebstein's anomaly. As time goes by, some patients will develop increasing valve leakage, and sometimes arrhythmias of the heart beat. If your child complains of palpitations let your cardiologist know. Finally, tricuspid valve stenosis (blockage) is extremely rare in general. As such, if the tricuspid valve is structurally abnormal, your child will need long term follow up, as things can change as they grow.
Many thanks for your comprehensive reply. I shall certainly ask the specialist about Ebstein's anomaly. It is a change in the "whoosh" sound that is heard. He explained that the valve is too long which causes it to take longer to do its job (sorry for the unmedical explanation) and this is when the backflow occurs. We are currently on bi-annual check-ups with the option that should she present with any symptoms we can go back earlier.