While sleeping (during the night only) I feel as if my heart has stopped and then all the blood seems to go into my lungs. I can feel the stopping and then I feel as if I am drowning and cannot breathe. I wake up so quickly gasping and then the sensation is gone.
This happens about once a month.
Otherwise healthy female, no meds, 180 lbs, non-smoker, light drinker (1 drink a week), eats a healthy diet, some caffeine but not a lot.