I first got them at age 30, they lasted for 4 hours, happening every 30 seconds. It would feel like my heart would stop, like a hollow feeling at times and then POUND. They have been happening on and off SINCE then (I'm 55). I also get the kind where I feel fluttering in my upper chest/throat and it will tickle and I have to cough. It kept happening when I'd start to shovel snow this past winter. (all it would take was for me to LOOK at a snow shovel and the fluttering would start!) I finally got mad at myself and plowed right through it and they stopped. And yes, you WILL feel it in your pulse. I had tests for that back when I was 30, then I had other tests in 2010 (echo, nuclear stress test) - NO problems at all. I was getting them pretty bad again last week, every few minutes for an hour or so. They'd start around 5pm! I'm fine again. They say it's very common.