Use of biofeedback

I'm sorry that you are having panic attacks, but recognize that your body is communicating with you.  It's letting you know that something within you needs to be addressed.  Yes, biofeedback can be helpful, but I would sooner recommend neurofeedback and some therapy...possibly hypnotherapy which can help you get to the root of the problem and not just stop the symptoms.  Understanding what causes your panic is germaine to solving the problem.  Neurofeedback will work to balance your brain activity, and is really effective.  I have found it to be more effective than biofeedback because it works directly with your brain and doesn't require you to "practice" as biofeedback does.  It is absolutely non-invasive, no negative side effects, etc. You can google it for more information and to find a provider near where you live. 

Therapy would also be helpful so that you can learn to understand what triggers your panic, since your MD has said that you do not have "panic disorder" then please give yourself the gift of getting to the root of the problem.  Symptoms arise so we pay attention to what we need.  You have a few possibilities to deal effectively with this problem and get really good results.  I wish you well, and hope that you'll look into some of these modalities.  All the best, Loren