I am 41 yrs old, about 5 6 140lbs. excercise regularly (such as The Shred dvds, etc). Have been diagnosed with Mitral valve prolapse , but take no meds for it. My concern is that, about 3wks ago or so, as I was wking out I got a sudden throb of pain in middle of my chest . No other pain, shortness of breath(other than to be expected since I was excercising), no dizziness etc... It has happened since maybe four more times or so. Today, I barely even got started in my wkout and it did it again, only more than just one throb, several. When I stop the exersion, it goes away?? What is your opinion?