What Causes Vasovagal Syncope In A Heart Patient?

Goodness, I was only after an article but.... my husband has a heart mummer and has had vaso vagle episodes in the past that have landed him in the hospital.. at one time they thought he may need a pace maker. The past week he has been having diziness that only lasts a few seconds and then passes but today he has had about 5. We are motorhoming and about 2 hrs away from home. Wondering how serious this might be.... sorry about the spelling. I've never recovered from my 3rd grade teacher. Thank you.