I also experience heart palpitations and panic attacks at the same time. I have been officially diagnosed with mitral valve prolapse (MVP), which is where the valve that separates the upper and lower chambers of the left side of the heart does not close properly. While I have yet to be diagnosed with panic disorder (it looks like its coming soon though) my doctor has told me that many people who have MVP also have panic disorder. Apparently its quite common.

I do not know if you have MVP as well, but I will share with you what I do to cope or prevent them. I have been told that MVP is something that you just have to live with, and most likely is not super serious. Like panic attacks they can be triggered by stress, caffeine and alcohol. I try to get plenty amounts of sleep, avoid caffeine and other triggers. When they do happen and if they are minor and my pulse relatively normal, I try to remind myself that my heart is fine and everything is all in my head. I usually try to distract myself with friends and the palpitations go away or I stop noticing them and clam down.

Hope that helps. You should probably talk to a doctor about your palpitations. Simple tests like an ECG or an ECHO can identify what kind of palpitation and if they are serious or not.