thanks for writing to us.
since this problem is over the years, and you did not have any episode of loss of consciousness/ blackout/ cardiac arrest
, then possibility of this rhythm disorder to be life-threatening is really low.
to understand your problem, we must know the type of "racing of heart beat" you have by looking at your ECG at the time of event. what did your loop recorder showed? any drug to control your heart rate
will take some time to show its effects, so relax. let us know what was there in your loop recorder. and if you have had an ECHO in past? What did it show? feel free to revert back with this information.