Happy New Year to you
Are you having any chest pain? What medicines are you on, if I may be so nosy

I know that you are on a beta blocker, but what dose of which kind?
The medical literature says that when your cardiac troponin I level ≥1.2 µg/L, you most likely have had a heart attack, if you have other findings such as mentioned in the following NIH medical literature. "In the consensus document of the Joint European Society of Cardiology/American College of Cardiology (ESC/ACC) Committee, myocardial infarction is defined on the basis of pathological findings or on the basis of a typical rise and fall in biochemical markers of myocardial necrosis and the presence of at least one of the following: ischemic signs and symptoms, electrocardiographic (ECG) signs of ischemia or necrosis, or a coronary artery intervention."
It seems you had ischemic signs and symptoms and high troponin I levels. so that can be enough to diagnose a heart attack, if the "clenching in the center of my chest" was due to lack of blood flow to your heart, BUT your angiogram showed that your arteries were clear, which is great. This usually rules out ischemia, but angiograms are not always 100% correct in finding blockages.
I know of two women and myself who would have had blockages that would not have shown up on an angiogram if not for the IVUS (Intravenous Ultrasound) technology. My angiogram that used the IVUS was done at the Cleveland Clinic. There was an 80% blockage at the beginning of my Lad. My doctor explained all of this to me during the angiogram. To me this is amazing. A blockage that could have killed me later on would have been missed by the contrast dye and fluoroscopy.
I didn't write the above to scare you, but you might ask your doctor did he use IVUS during your angiogram. I think that all of us should be aware of this. My story sounds like a tall tale, but it is the total truth, as explained to me. Maybe this doctor had lots of shares in those that manufacture the IVUS technology? Ha ha ha.
Another thing is the troponin I levels stay elevated for at least a week and most times two weeks after a heart attack, I have read. Yours decreased to normal soon after the event.
Most heart attacks cause some damage to your heart however slight.
One thing for sure your BP was extremely high. The "dizzy and tunnel vision" you had could have been signs of an impending stroke.
Watch out for chest pain. Learn how to recognize changes in your chest. Tightness in the chest can lead to an increase in tightness in the chest due to anxiety. I know because I can bring it on, at will in myself. You just have to keep it off of your mind. It is a sign of a developing heart attack, i.e.
"feels like someone is sitting on my chest" scares the ER folks.
Best of luck to you