Some people hyperventilate to the point of fainting when they have an anxiety attack. My sister hyperventilated. I don't, so we do differ. It's possible the initial anxiety attack was related to fear because of the heart problem, but we can't know that really. CBT might be very helpful to you given it's mostly this one experience that triggers them. Might make it easier for that type of therapy to work. If it's still happening then the meds you're on aren't working at the current dose, assuming you're been on them long enough for them to start working. Because they seem to be tied to this one experience and aren't happening all the time everywhere, it would make it less likely for there to be a physiological cause. If it was physiological, it would probably be happening randomly, even just while sitting at home relaxing. I'm also not sure you're describing GAD -- that's when you're anxious all the time. What you have sounds like you've developed a phobia to eating at restaurants, unless there's a lot more to it. I suffered from phobias, and they only bother you when you're in the situation or facing having to be in the situation. GAD is all the time, I developed that from Paxil withdrawal. Never had it before that despite the phobias. The diagnosis can affect the type of therapy and relaxation techniques that might work best, but anxiety is anxiety.