What does it mean when my heart just all of a sudden started quivering and feeling like it is spasing out. It s been doing it for about a week or so now off and on almost every day. Can you advise on this? I am in good health and recently started working out at the gym about 2 to 3 days a week. My heart has never done this before. I do not get short of breath or get chest pains, it just feels like my heart is quivering and beating funny. I can feel it in my chest if I put my hand there, it feels like a muscle spasing out. Please advise thanks.