Hi Carnelian.
Most of my echos have been standard echos, but when my aortic stenosis was first diagnosed with a normal echo, my cardiologist ordered a stress echo, which involved a Bruce Protocal treadmill stress test and an echo.
So, I did ask some questions and this is what I was told for my own situation. He indicated that he was specifically looking for my blood pressure response to exercise. Blood pressure is supposed to rise gradually with increasing exercise. But with aortic stenosis, particularly advanced, blood pressure will sometimes drop with exercise, which can lead to syncope (fainting), which might be an indication for surgery. As it turned out, my blood pressure rose gradually with increasing stress, as it is supposed to.
Also, the tech who conducted the echo explained to me that with the increased work load on the heart with exertion, they are better able to evaluate diastolic function- does the heart show the flexibility with expansion(during filling) and contraction as expected, or is there rigidity, which could be an indicator of diastolic dysfunction. I had mild left ventricular hypertrophy, and as this progresses, often the ventricular walls do not have the flexibility with expansion that they should have.