This test I had yesterday, and I have an appointment with the consultant on November 24. The objective is to determine the cause of my shortness of breath on exercise, which may be due to narrowed coronary arteries. Considering that its 15 years since I had the bypass operation it wouldn't be surprising.
One of the valves isn't closing, but that wouldn't account for the problem. At the moment I don't get to the shortage of breath, because I can only walk at a modest pace before claudication kicks in with my left leg. See www.medicinenet.com/claudication/article.htm#1whatis.