I was curious to know how worried should I be when experiencing palpitations. I am a 46 yr old female. I have had a number of times during the day when my heart feels fluttered and never gave it another thought. Last night, shortly after falling to sleep, I was awakened by the thunderous pounding of my heart feeling like it was going to burst. This went on for about 20 minutes. The only reason I know how long it lasted was because I glanced at the clock when I awoke and somehow text someone about a half hour or so later. I must have fallen back to sleep, I don t remember if I passed out, I don t remember much at all. I am otherwise healthy. Quit smoking two months ago and with that reduced caffeine to one cup of coffee in the am each day and I rarely drink alcohol. How concerned should I be?