patmob, if I may ...
I remember noticing this, too, way back when, especially when I would lay down and try to go to sleep after a relatively large or rich meal. I'd also notice that my heart rate would drop significantly if I could manage to make myself burp, or work out a lingering air pocket. Anyway, point being, I began to notice a corollary between the two and (naturally) looked it up online and read that it has something to do with an irritated vagus nerve. Still, knowing all this, I went to the ER once for it, where I was given a GI cocktail and diagnosed with GERD.
What I'm saying is, this is no big deal. It happens, and it probably happens all the time, it's just that you're noticing it much more easily now. I'd recommend that you NOT go to your GI doctor for this. All they're going to do is shrug, scoff at the vagus nerve connection idea, and probably tell you to take some antacid. Why? Because what you're describing doesn't signify that anything is "wrong," this is simply unpleasant, and you make it worse by getting freaked out, or by trying to limit the foods you eat to only the ones that won't make your heart rate speed up. Well, soon you might not be able to eat anything—then what do you do?
I hope this doesn't come off as harsh, because I don't mean for it to be, but the key to getting past this is, when you notice it happening, ACCEPT the fact that it's happening, and try with all your might NOT to assign some sort of catastrophic meaning to it. Sure, certain foods might cause a rise in heart rate, but so what? It doesn't mean one single thing from a clinical standpoint.