I had something like that.
After wearing a monitor...and After being put in the hospital for a week with all kinds of tests they finally did a tilt table test .
I didnt believe it would have any effect on me. Next thing I know I am flat on my back after my heart stopped beating. Wild disorder.. vasodepressor syncope.
I think my sister must have that too. She would always faint at the sight of blood when she was a kid.