question: I m 45, 145lb,5 3 . I ve been experiencing abnormal heart flutter/pounding that awakens me during the night. These only happen while I m lying on the left side. I ve had it happen prior to getting to sleep but lately it s becoming more often. I had an excercise stress test/scan about 4 years ago which was normal (I m on a beta blocker to help prevent migraines)