Just wanted to chime in and add my own experience to this thread for future reference. In 2011, I also had the faux heart attack from TOS though I didn't yet know I had TOS nor had I ever heard of it. I went to the ER where they gave me a nuclear stress test, cardiac enzyme test and of course examination. All was clear. After I was partially recovered, they kicked me out with no diagnosis but still sent me a hefty bill.

Next I want to a cardiologist who reviewed my ER records, gave me an echocardiogram and examination. He said my heart was perfect. His diagnosis was a virus that temporarily affected my heart function.

I continued to have more episodes. I told everyone about the funny arm numbness and coldness in the weeks preceding, but they couldn't connect the dots.

In hindsight, vascular TOS is exactly what I had. Compression points included pec minor, under the collar bone and the scalenes. Propping my left arm up in order to raise the shoulder girdle and collar bone gave me substantial relief when my symptoms flared.

Btw I could feel my heart cramping which is a strange and awful sensation. I presume that flow was backing up and reducing the rate of circulation through it.

These days I keep the collar bone down and the rib up. I stretch the pec minor. I haven't yet gotten control over my scalenes, but my chiro works on them. No more faux heart attacks.