The ECG is very good at picking up electrical faults of the heart but the echocardiogram is a much more detailed investigation that looks at structural abnormalities of the heart. So, minor holes in the heart, minor valve problems will be missed by an ECG but will be picked up with an echocardiogram. In my experience, about 1% of people we screen have such minor abnormalities that are only picked up on a cardiac ultrasound.
