I've had bouts of tachycardia since I was 19 but didn't have to medicate until I was 26. My heart just stayed in over drive. An echo showed nothing wrong with my heart except tachycardia. I take Tenormin (atenenol)I started out with 25 mg of a morn then I had to up it to 50 mgs of a morn and 50 at night! I also have to take mine before I even get out of the bed of a morning..So my heart won't be raising by the time I am in the kitchen ! So...I am now 36...I never have racing heart episodes any more unless I am VERY stressed or have drank too much coffee (which is a No No) and I do smoke...But I know my limits with all the above. I drink very little coffee...It's mainly diluted water with sugar and creamer! LOL! But I hope you don't let this over run your mind. Just for peace of mind..Talk to a doc..and let him/her tell you Exactly what your experienceing...You might be surprised at how low of a heart rate you'll have once you talk to one also. Mine was sky high..169 bpm then they said I was fine...and it dropped down in the 80's!