I have had chest pain with my AFIB though I don't know it was the Paroxyml type. What I learned with mine is that almost ever time I had AFIB there was significant stomach gas along with it. I was told by my physician that many people experienced the same thing. As my AFIB would back off, the gas would come up and the "chest pain" would go away. One thing I learned during those experiences was that by slugging down some apple cider vinegar, it generally made my AFIB go away and it got rid of the gas. I still believe that some my AFIB was associated with what I ate. I believe that to be true for others as well.
How I got going on apple cider vinegar is that I was diagnosed diabetic a couple of years ago and in browsing around I found that ACV has lowered blood sugar when taken before meals. That was in a study at the University of Arizona, a small but significant one. So, I kept it on hand, tried it and didn't seem to work for me. Then a little over a year ago I went to a high school reunion luncheon and ate way too many carbohydrates including bread, cheese cake, and other deserts. When I got home my chest was pounding with what I now know was AFIB (it hadn't yet been diagnosed), and I immediately checked my blood sugar and found it to be about 220. My normal BS after a meal is around 95 - 110. My chest was really uncomfortable from the pounding and I thought that it was acting up because of my high BS. So I started chugging ACV. Started with almost a 2 ounce shot glass full and nothing seemed to happen. Then another almost full shot glass, and this time the heart began to come under control so I gave it another shot. Within a half hour of my first BS test, I tested again and it was 85 and my heart felt completely normal.
I still generally take ACV with a meal and when I've eaten something out of bounds, I do it double. (I'm on the Virginia Mason Diabetes diet which is no more than 15 carbohydrates per meal, for a total of no more than 45 per day. I found that if I violated that, my AFIB would often kick in, particularly with bread and potatoes.)
Three months after the above HS reunion incident, I was diagnosed with AFIB on an EKG. Rather amazing how those things seem to go together, a significant problem, and not too long afterward either a solution or a diagnosis. It's happened to me several times in my 76 years.