I've posted many times on the vagus nerve connection, and you can search the old messages by putting a few words in the search box at the top of the page. Try "linked angina" or "cardioesophageal reflex." You can google the terms for the scientific papers.
I have had tachycardia and angina incidents for many years that were brought on by my esophagus and stomach not tolerating certain foods. My stomach would churn after eating certain things, and then I would have reflux or heartburn. After that I sometimes developed a rapid heart rate (tachycardia) and chest pain. My allergist had me keep a food journal with times, what I ate, and symptoms. I usually react in half an hour to two hours. Other people, who have migraines, can have a reaction as much as two days later.
I found my food triggers: gelatin, corn starch, many prepared foods, maple syrup, and several medicines, plus a lot more. I googled a few of them with food allergy and found all my triggers contained sulfites. This is not the only trigger that is possible, so don't assume you have the same one unless you have problems with the same foods!