good thread. I even wrote in it  

I recently start having contact with some doctors and they both told me that trapped air, hyperacidity in stomach can easily increase palps. increase chestpain. The feeling can be scary they told me .
Also when having hiatus hernia , the diaphragm isnt used 100% so a chance of chronic hyperventilation state increases which gives more palps and anxiety like symptoms, chestpain and all kind of symptoms.
I was happy that it wasnt just anxiety that was the culprid in their eyes but that anxiety can be a cause but often is just a an extra addition of other causes that are the real problem.
I could totaly relate. Off course arousal plays his or a role. I will never deny that. but my symptoms probably come and came from hiatus hernia, hyperacidity, and more GI problems

Sounds like something called the Roemheld Syndrome.

Again it has todo with stimulation of the vagus nerve.