How useful do you think echo-cardiograms are? I had one done last year, they said I was clear of plaque or any blockages or narrowing. My weight is high, but my BP is normal and my cholesterol is OK for 'bad' and low for 'good'. I do have a family history of heart attacks; that's what killed my dad at age 61.
Echocardiograms show valve function and movement of the heart walls. They cannot directly demonstrate the presence or lack of plaque buildup. They can do so indirectly.
During exercise, the coronary arteries expand, allowing more blood to reach the cardiac muscle. In the presence of heart disease, they cannot expand enough, and the blood flow will no longer supply the oxygen needs of the muscle. If it's severe enough, you may have chest pain, EKG changes and other symptoms at this point. Even if it's not severe enough to cause symptoms, however, the lack of adequate oxygen will lead to a decrease in the movement of the heart wall.
Usually, (and I presume this is what was done for you) the echo is done at rest, and then repeated with either physical exertion or chemical stimulation of the heart. This is called a "stress echo". Dobutamine and/or atropine are the drugs most commonly used to simulate exercise.
Stress echos are considered highly reliable, second only to heart catheterization. If you have a negative stress echo, then your chance of having a heart attack within the next few years is thought to be about 2%. If you have a positive stress echo (meaning a decrease in heart wall movement without symptoms) then your odds are more like 20-30%. If you have symptoms during the tests, you're likely to be going straight to the cath lab rather than home.