heart palputations

For the past three years I have had heart palputatuons happen out of nowhere.  Sometimes it happens when I am exercising and sometimes it happens when i am just sitting down or walking.  In the beginning the heart palputations would only last about 20 to 30 seconds, but through the years the palputations have been lasting longer.  My most rescent one lasted about 8 mins.  When these palputations occur my heart beats faster (almost as if my heart is pounding out of my chest), light headedness, dizzyness, shortness of breath, , claminess, and I get 2 or 3 shades paler.  Also I get very tired and weak.  My tiredness will last will last for hours after it has happened.  I have been to my doctors repeatedly.  I went through 2 EKG's, heart monitors, blood tests, and other tests that i can't remember exactly what the others were.  The only thing that the doctors found was in my blood and that was that everything( blood pressure, cholestrol, etc...) was low.  My platelets were the only thing blelow normal.  I think my the count was 126 thousands, last year it was 137 thousands.  I just want an idea of what could be wrong.  What are some possiblities?  Please someone give me something.

[Michael J. McWilliams, M.D.]

If they can't catch a arrhythmia on a monitor, the next option is an invasive procedure called an EP study.  An EP study is done by placing catheters in your heart and adding extra beats to try to induce an arrhythmia.  If it can be induced, more pacing tests can be done to try and determine the mechanism of the fast heart rhythm is and if it can be ablated (heated to locally kill the heart muscle and prevent further arrhythmias).

I would recommend seeing a cardiac electrophysiologist to help determine what the likely mechanism is.  It may be fixable.