Heart rate jumps too high during exercise

[twinjockey]

Two days ago I was 35 minutes into an interval workout. My heart rate was peaking around 158 at the hard intervals and droping to the 140's for my slowdowns. Twice since October my heart rate, for no reason that I can find, has jumped to 205 during the hard interval for about 20-30 seconds then has returned to normal, 135-145. It is not a heart rate monitor malfunction. I can feel it. I also feel a little light headed. I have asked my cardiologist and each time he has said he has no idea. Two years ago I thought I had had a heart attack, but it turned out to be a cardiac muscle spasm or a small clot that broke and disolved. They did a heart cath which showed zero blockages. I was cleared to exercise pretty quickly after that episode. I am 53, in good shape, no family history, non-smoker and exercise regularly for an hour a day. Anyone have any ideas? None of the trainers do.

[twinjockey]

I found it odd that he said that, as well. I did not do the stress test since they did a heart cath. This happened because my blood enzimes elevated. The doctor, however, said that of the several hundred caths he does a year, he will see a few like mine where the enzimes elevated but there was no blockage or problem. I did start taking a 325 mg aspirin every day two years ago. I also found out this year that my father has Factor V which means I am pretty well assured of having this issue as well. His blood clot issues did not start until his 80's. I did a EKG in July when I went for my one year followup visit and it was ok. I have to be careful because I am a pilot. I will ask my FAA doctor too. I also have a couple of friends that are cardiologists and cardiac surgeons to get their take. Thanks

[rr2465]

If these elevated HR symptoms persist and your cardiologist still "has no idea" I would suggest finding a new cardiologist and trying to get an echocardiogram, stress test etc. to rule out structural abnormalities.  It could be electrical but you need to have a few more things looked at before the cardiologist just gives up.  If you are monitoring your heart rate regularly, I would assume that you are familiar with your body and what is and is not normal.  Stick with your instincts and find a doc who can help you.

Good luck!

[Jerry_NJ]

Seems strange a cardiologist would say "has no idea".  Sounds like you've got a clearance on, or no need for, bypass/stints, but what about the structure of your heart?  Did the cardiologist do a echocardiogram?  Or, pur you on a 24 hour or longer heart monitor?  Seems like s/he would need all that data before saying "no idea", or said another way "no problems found, you are fine".  

If you are not doing so, you may want to consider taking an aspirin every day, the mention of a clot raises concern, and the short periods of high HR raises the possibility of PAC and/or PVC.... or AFib/Flutter.  Clot formation is very risky.