During my struggle with GERD / REFLUX / HIATUS HERNIA etc. and having seen many Gastro and Cardio doctors you have been the only one to openly mention this correlation.
Personally there are a few ways that I manage this and try to live with it as it can be very uncomfortable and disconcerting.
1. Dealing with this with professional counseling and the mental aspect. Accepting this condition and that some days may be worse than others. Overcoming the anxiety that you do not have a cardiac issue.
2. Eating consistently throughout the day and small portions. Not eating after 6pm.
3. Hydration is key.
5. Lose weight.
6. Personally have found that the PPIs aggravate my palpitations and general unwell feeling.
7. Breathing exercise focusing on deep diaphragm breathing.
8. Maintaining a mental and physical balance and the TOTAL acceptance that this is sinister and will not kill you.
I can only comment on these now as I do feel after almost 7 years of this battle that I am moving in a direction where I can live with and try tolerate these symptoms. It is difficult.