Most likely, your panic attacks are "genetically related". Therefore, what works for one person - won't work for you. I have had heart palpatations, anxiety, and panic attacks for a long time.
First of all, AVOID all caffeine and chocolate! Also, get a Cardiologist to do an "Echo-Cardiogram" test on you to see if you have "Mitral Valve Prolapse". This is a condition that 75% of women have, but don't always "know" it. It causes symptoms of anxiety due to the Mitral Valve NOT opening and closing as it should. I have been on .25mg of Lanoxin for 24 years to control this. I also have anxiety that runs in my family genes. I take Valium and Neurotin for this. These medications have helped me a lot! The Neurotin is a fairly new medication... and I take about 4-5 a day. I also have been prescribed Seroquel, to help me sleep 25mg. All of these last 3 medications that I mentioned would have to be prescribed by a psychiatrist. Do try it, they have helped me immensely!!!
Don't suffer... without getting help!