racing heart beat

I have had a racing heart beat - 100 - 150 bpm.  This has been going on for the past week.  I have gone to the er 3 times - and the ekg etc is ok- Is there a point that a heart going at this rate will hurt itself?  My chest hurts, I am short of breath.  This happens every afternoon into the night.  I wake with a 100+bpm every morning.  The lowest it has gotten is 78bpm - that was with demoral.  What should I do?

[Douglas Bogart, MD]

You need to see a cardiologist and have an evaluation and a 24 hour monitor to determine the cause of your symptoms.