It's Vagus nerve stimulation. The top of the stomach holds a cluster of nerve endings, the Vagus nerve. When you eat a lot, or for me, after an aggressive fill, the increased difficulty and extrusion of food through the band, causes vagus nerve stimulation. Stimulation of the vagus nerve causes all kinds of nasty arrhythmias. Baring down or coughing also stimulates the vagus nerve. After 20 years of being a medic, I've seen more people die on the toilet, than any other method, baring down. I have the same problem with palpitations having never had them prior to surgery. Honestly, with fear of litigation, no physician will ever admit they might have done something that may have caused a heart arrhythmia. Think about every time you have ever been to the doctor, have you ever heard the words, "oops?" There is a reason they call it practicing medicine. Everyone is different, there is no "normal" and no diagnosis will ever fit someone else with the same problem. My solution was to make sure than I drink pretty of water, and either back the band off a bit, or wait for your body to adjust to the new restriction.
