Went to er heart feels like it stops then big thud and goes to normal.. happens throughout the day.. all tests are normal.. what can it be?

Arhythmia: You may have an abnormal heart beat, that is intermittent. See a Cardiologist who can do a 24 hour holter monitor (or a week), which will monitor your heart rate and rhythm for a longer period than a 1 minute ekg. You can make time stamped diary entries and then the doc will compare to your rhythm at that time and be able to see exactly what is going on. Good luck.

Felt beat: While you might or might not skip a beat now and then, you likely are having an occasional PVC (premature ventricular contraction), which is originated from a different spot on heart and often out of phase with pulse, so you notice it. Stress, CAFFEINE, tobacco and other stimulants can bring them on. Cut back on these, sleep enough (7+hrs/note for most folks) and they should tame down.

Pretty good: description of a ventricular premature beat which is benign if less than 1-2 per minute. You could see your doctor for a 24-48 hour event monitor to be sure it is notheing else.

Irregular heartbeat?: There are many types of irregular heartbeats that can cause this type of feeling. Many if these would not show up on an EKG at the ER. See your doctor and get referral to a cardiologist. Good luck!