I can feel my heartbeat harder than usual, several times a day. I have undergone electrocardiography (ECG), and the nurses told me that my condition is normal as my heart often takes a few milliseconds longer breaks in between beats, so they work hard to catch up. However, for me, this sounds like arrhythmia. I want to know if this is normal or arrhythmia? I do a lot of fitness workouts, and I wanted to make sure that I am not putting myself in danger. Thank you.