Lyme and 'Exercise Induced Tachycardia' ?

Hello. I am an age 45 M in NY. I am athletic and have been 'cured' of Lyme by 3 weeks of Doxy a few times in as many years. One of those times the symptoms seemed more like Ehyrlichiosis but that was not confirmed.

I'm having some difficulty finding diagnosis and treatment for my symptom: It is as if my heart has a restriction, as when I go beyond moderate aerobic efforts my chest pounds hard and I need to stop to rest. My breathing is not quite as fast as my HR, and breathing seems clear (Ive ruled out Asthma and allergies). It only takes a minute for my HR to be normal and there is no pain or dizziness. I must limit my aerobic efforts to about 60% of what is normal for me. I can barely jog 100 feet before needing rest. This is my only symptom.

The effect has been of varying severity for 3 years -sometimes seemingly gone completely. For the past 3 months it has been mostly steady. In recent months, I have had a few occasions where my athletic performance seemed 80% normal.

I have seen no correlations between diet, environment, etc. I have a healthy family history, and none similar to my symptom.

I had my thyroid removed 30 years ago, though my T4, Tsh etc #'s have been steady all along. I take generic Synthroid daily.

I began seeing a cardiologist last month who feels that I am at little risk of a serious issue, based on recent EKG, Echo, bloodwork, and a stress test (on treadmill). Nothing out of the ordinary so far.

I have not been diagnosed with 'Exercise Induced Tachycardia' -it seems similar to my symptom though.

Any ideas if Lyme can be the culprit? Or further information? Thank you!

Post Edited (timxtr) : 12/17/2014 10:45:00 AM (GMT-7)

Thanks for the reply, but to clarify my cardiologist has found nothing of concern yet. Nothing was abnormal.

For instance, I can hike all day but I can't jog more than 100' before experiencing a rapid pounding HR. I have to go slower hiking up mountains. No irregular beat, chest pain, or dizziness.

While you've gotten a pretty good cardio workup, your doc might agree to a 24 hr Holter test.
That way you could go out and induce the problem, creating a record of the heart's rhythms during the event.
When I did this I kept an activity/symptom journal that I handed in when I returned the monitor. It allowed my cardio to see that treadmill exercise was inducing VTach!

btw, my heart rhythms and rate totally normalized at week 3 on abx, and have remained steady as a clock since then!

also btw, Bart and BLOs have a rep for inducing this type of heart problem too. If untreated for too long, Bart will eat your conduction system and you end up with a nonreversible heart block>>pacer>>no fun.