How can a stress test be abnormal but angiogram show everything good with your heart?

Anyway, I've had the same tests run on me over the last two years. Angiogram and nuclear stress test. Plus I've had multiple holter monitors for weeks at a time. I pressed the button during one of my "panic" attacks to record them. But all they recorded was that my heart rate increased. No abnormal rhythms. I was sure I had something wrong with my heart, and every time I have a panic attack, I feel like I'm going to die and fall to the ground.

I had a very massive "panic" attack at work several weeks ago. It felt so bad, like it affected my heart, that I went to the emergency room to get checked out. But all blood work and tests on my heart were normal.

Panic disorder is very crippling and I hate living with it.