Heart murmurs indicate damage to heart valves. How could heart murmurs be produced? What effect would the valve damage have on heart function? Would you expect to see evidence of valve damage on any ECG?

The heart is a pump and like any pump, normal function requires that blood moves through the heart in the right direction, and that the heart can generate pressure to fulfil its pumping function. The heart valves make an important contribution to enabling the heart to meet both requirements. The valves prevent backflow of blood into an area from which it has already moved, and the closure of the atrioventricular valves enables pressure to be generated in the ventricles. Heart murmurs other noise that occurs when blood travels through abnormal valves. The abnormality could be a leak that is caused by valves that do not close properly due to some sort of valvular damage, or it could be the noise that is created when blood is pumped through a narrowed valve. If the valves are leaky they are said to be incompetent, and valve narrowing is known as stenosis. Abnormal valve function has an adverse effect on heart function. The effect will depend on which valve is affected and how severe the damage is. You won't necessarily see evidence of valve damage on an ECG because an ECG is a way of monitoring the electrical function in the heart whereas the valves contribute to the mechanical function of the heart. However, if valvular disease causes changes in the structure of the heart these will become apparent on the ECG.