A panic attack will stop, eventually. If you are having a heart attack the pain will stay.
I have had severe anxiety for many years and also had a heart attack a year ago. Believe me, you would know the difference.
I recommend checking out this link http://en.wikipedia.org/wiki/Anxiety
I have'nt checked out the link you sent, but I will. I do know that when having a heart attack you can also have anxiety.I've had anxiety for more than 30 years, so I do know the symptoms because I've had most all of them. Some people do and some people don't have anxiety when having a heart attack. Also, many of us can have different symptoms. I did not have the common symptoms of chest pain, sweating, arm pain, none of that, not even anxiety when it was happening. What I recommend to anyone is listening to your body. If you feel like anything strange is going on, get to the hospital. If you're a woman like I am, research symptoms. Women, and some men do not always have the common symptoms.