I call them palpitations because of the fastness of it. So, as soon as I start to move it goes up. And when I'm walking it can get to 120 or sometimes a little more. And its fast. It use to feel like it was beating out of my chest. It sometimes still does that. I notice them because of my fitbit. Both symptoms came on suddenly. I started on a blood thinner and 2 weeks later they started. However prior to that it felt like my heart was "jumping" and I couldn't sleep. Then that stopped. Then did it again for awhile. Then that stopped. Now its fast heart rate. When I sit down it goes down. Sometimes to 59. These symptoms happen on exertion and sometimes when I'm sitting I feel like I have to take a deep breath and can't