Abnormal Stress Test Results - Age 27

Hello,

As a disclaimer on my part, I'm not looking for a diagnosis - I realize that only my cardiologist will have to be able to accurately diagnose what's going on.

I had a stress test on Friday, and I "failed" miserably. I'm a 27 year old female with symptoms akin to either congestive heart failure or Cushing's (not diagnosed - symptoms include pitting edema of all extremities, really rapid weight gain, shortness of breath upon mild exertion, coughing when lying down on my back, general malaise/fatigue, etc.). I am 215 lbs, but was symptomatic 3-4 months prior to the weight gain when I was 140 lbs. Anyway, I was explained that the stress test is useful in diagnosing coronary artery disease and ischemia. I was also explained that every three minutes they would increase the speed and incline and would notify me beforehand.

I was on the treadmill at baseline when they told me they would be increasing the speed and incline to the next stage. About 1.5 minutes into the second stage of the test they had to stop because I reached my maximum target heart rate of 165 bpm. The on-site doctor informed me that there were also abnormal changes seen on the ECG and I now have to follow up with my cardiologist.

My question is *if* I have ischemia or coronary artery disease or something along those lines, would it be almost expected that my heart rate would reach the target maximum heart rate upon such low workload? I mean I was aware that I had decreased tolerance to physical activity, but I didn't think it was that low. I was barely feeling short of breath at that point. Can a potential disease process underlie such rapid heart rate upon exertion? Or could it also be partially a factor of my carrying 80 lbs more than I'm used to? I'm just looking for some theoretical explanations here.

Many thanks!