After a month without them, mine are creeping back. Was to a podiatrist today, I have neuropathy in the feet, had it for years, but it's annoying me now (it's hard to explain how not feeling something can annoy, but it does). The office was austere, but I'm impressed with the doctor. As with so many medical issues, it's more a rule-out approach, but he mentioned as possible causes of the neuropathy deficiencies in certain vitamins, such as folic acid, B-Vitamins, Iron, liver problems, and more. He's doing more blood tests to understand my feet numbness than my cardiologists have done to understand my heart rhythm issues. I'll anxiously await the results, if I'm anemic (and I do indeed feel run down even getting enough sleep) it may be a factor in rhythm issues.
But with my return in rhythm disturbances has come profound roiling in my stomach, and as you explained in your post, there is no doubt a segment of people with rhythm issues caused, or exacerbated by GI disturbances.
I labored through the one article on GI Tract correlated heart rhythm disturbances, but it is noteworthy that they addressed intestinal pacemakers, something that, through the regulation of smooth muscles of the GI Tract, sustains peristalsis, or the orderly movement of intestinal content through the GI Tract. They seemed to be inferring that an uncoupling of the GI smooth muscle signals can effect the heart, since the heart also uses similar modes to conduct the heart's pacemaker signal throughout the heart.
Word of the day, "Borborygmus", pertains to the rumbling sounds made in the GI Tract. At this point, you can hear mine from across the room.
An interesting article on this effect can be read here:www.scientificamerican.com/article/why-does-your-stomach-gro/
And, they have, in part, this to say as well.
"The generation of these waves of peristalsis results from a rhythmic fluctuation of electrical potential in the smooth muscle cells, which, all other conditions being appropriate, will cause the muscle to contract. This fluctuation is called the basic electrical rhythm (BER) and is a result of inherent activity of the enteric nervous system, which is found in the walls of the gut. The BER causes the muscle cells of the stomach and small intestines to activate at a regular rhythm (three and 12 times per minute, respectively), in a manner similar to, but slower than, the rhythmicity of cardiac muscle in the heart.
The autonomic nervous system and hormonal factors can modulate this BER."
Learn new stuff everyday.