Welcome to HealingWell. Gastric causes of heart rhythm disturbances are well known, unfortunately not all doctors are aware of it though.
Good to hear of your success.
There are multiple things that may be the cause, hiatial hernias, esophagus pressing against the heart, autonomic reflexes (sympathetic and parasympathetic nervous systems), diverticuli, etc.
Thanks for posting what you did to successfully overcome it.
I have included a link to an article that discusses some of the technical aspects of this problem.bjcardio.co.uk/2009/07/cardiac-manifestations-and-sequelae-of-gastrointestinal-disorders/