Hi! My heart tests were always wonderful. Nothing showed with the event or Holter monitors. If they can, have them check your SA node...if there is a test for that. It's your atria's electrical system. My pacemaker is doing about 70% of my SA node's work. but less than 1% of my VA node's work. Which means my ventricles are doing their own work...not so much my atria.
In my case, I had to run to the doctor's office while I was having the attack. The ekg picked up SVTs. But it had to be caught during the attack.
Sorry, hit the key before I was finished. There can be missed or skipped beats in a healthy heart too.