rapid pulse and weakness with light exercise

[jh71]

Would appreciate any thougths.  I am 41 yo male, 6-1, 170 generally healthy.  I am a lifelong competitve tennis player.  I am no longer able to play due to very rapid onset of increased heartrate (130-140) and physical weakness immediately upon exertion. Heartrate stays persistenly high following cessation of activity.  Can tolerate stationary bicycle workout reasonably well but unable to run on treadmill.  Have struggled with this issue for 10+ years but recently has worsened to the point I can no longer play.  A few other things:
normal EKGS and stress echos.  no structural heart abnormalities.  normal Holter, no arrythmia,
pulmonary workup did not show any asthma
normal brain MRI and neuro workup
I have a past + tilt table test with 4-5 fainting episodes but none exercise related.
I have very limited tolerance for heat & high temps.
Last physical was recent with normal blood test results save for low vitamin D (now supplementing).  Normal thyroid (TSH level?)
Sorry to ramble but am getting desperate. For now I am being put on anti-anxiety meds and been told (by my cardiologist) to build up my CV fitness.  I myself think there is more going on than stress and being a little out of shape.  I get a 130 pulse with weakness just from walking up a long flight of stairs while carrying my briefcase.
Hoping someone can help, thanks

[merrialruns]

Hi, It definitely sounds like we have the same problem. I'm 48 and have been diagnosed with preload failure, otherwise I'm super healthy. I've been a runner for 18 years. Running has always been extremely hard for me but I loved it and could always manage to push through. I've completed over 40 marathons, a 50K, countless other races, and I weight train two days a week. At this point, however, I can barely run 20 min before I have to stop and let my HR come down. When I run my HR immediately shoots up to the 160s and continues to climb until it shuts me down, I've seen it as high as 200. I've just started posting my story on some of these sites hoping for some answers. I really don't want to have to stop running :(

[jh71]

My cardiologist and I did discuss wearing an event monitor at one point but he has not mentioned it the last couple of visits.  I will have to raise it again at my next visit.  I've done the fluid overloading (32 oz gatorade before I even pick up a racquet) along with salt tablets...with limited positive impact, if any.  Being well hydrated can't hurt but it has not been the difference maker I'd hoped.
As far as HR monitoring, iPhone has a 99 cent app that reads pulse pretty accurately...I've been using that (doing it on the cheap).  My cardiologist has actually discouraged me somewhat from obsessing about HR.  He seems to think I am in some sort of negative feedback loop (my terminology) that is at least in part pyschological, along with just being deconditioned, and being very "volume sensitive" (hence the need for extra fluids as you mentioned).  All of which make some sense; I just have some doubts b/c I am getting a pretty benign diagnosis for symptoms that, when they hit, are not at all benign...it is scary and debilitating.
I have seen Dr. Levine's name pop up on numerous threads on this site so I'll have to check him out some more if I don't see some progress soon.  Thanks for your input.

[Genome911]

Since this occurs under such specific conditions, it might be reasonable to consider an event monitor (continuous loop recorder) that is worn for about a month. If you haven't used one, it is triggered by you when you get the symptoms & the monitoring techs (remote) then go back a few minutes & download rhythm strip leading up to the symptoms as well as a few minutes after. The monitoring people call you so you can report exact symptoms & they notify your doc if there are concerning abnormalities. The cardiologist/ep also requests certain things that will automatically trigger a recording & phone call. The event recorders seem to be more revealing than Holter monitors in situations like yours. Just my $.02 but I'd check into event monitoring & increase hydration in order to have maximum volume during vasodilation during exercise, which is a part of preload you can control. If that doesn't work for you, have you thought of using one of the HR monitors (Polar or similar) that downloads data to your computer so you can take it in to show your doc? Just be sure to input your actual HR max from your stress echo... that 220-age default isn't accurate for most people. If that's negative, there are cardiologists who specialize in exercise phys problems/POTS/autonomic dysfunction, like Dr. Benjamin D. Levine, etc.

[jh71]

Have you been put on any medication to address the heat intolerance, and help your vasoconstriction?

[jh71]

One of my tennis partners who is a neurosurgeon basically theorized what you describe...that I get vasodilated, and that the signal to constrict the vascular system is faulty, or the body does not respond properly.  But I have a had exercise studies, treadmill tests etc that all showed a normal BP response to exercise.  Of course those tests occurred in a climate controlled setting.  My condition has worsened since I had those tests though.  I can barely play one tough point under any conditions..in the heat, outdoors...no chance...I am flat on my back with HR 140+ within 5 minutes.

I have never been told my EF numbers.  After one of my cardiopulmonary exercise tests (on a bike) the dr used the term "pre-load failure", which I think meant not enough blood being returned to the left ventricle...which could mean EF was low upon point of intolerance, but I was never specifically told that...suggestion was compression garments on legs, increase salt intake, more pre-hydratation etc...all of which I tried with no success.  I have never had any physical evidence of blood pooling such as swelling in lower legs etc.

[tom_h]

Did you get left and right ejection fraction readings?

[achillea]

I wonder what your BP is at the instant your heartrate accelerates and your excercise tolerance fails?  The reason I bring this up is that I am heat-intolerant.  I faint or become faint when the ambient temperature is above 80, especially if the humidity is high.

My cardiologist told me that this is probably caused by a failure of my nervous system to initiate constriction of the capillary beds to compensate for vasodilation.

This would be a possible explanation: If your brain thinks you're overheated, your peripheral blood vessels dilate to lose heat.  If your capillary beds do not constrict to make up for this dilation, you will feel faint as a result of low the low blood pressure--and your heart rate may increase in an effort to compensate for hypotension.

Just a thought.

[jh71]

Thank you for your answer.  I have considered POTS, dysautomia, etc but I don't really have other classic symptoms like GI disturbance or general fatigue.  My energy level is generally pretty good.  I have seen my cardio regularly and he has not mentioned IST as a possible diagnosis...and I understand this typically entails a high HR at rest, which I do not have..usually 60-75.

He has reassured me that it is safe to exercise.  I love to work out so I am happy to have that as a recommendation..I just can't do anything do intense, which is hard to accept as I have always been fit, active and very health conscious.

Also, my cardio had me try a low dose of midodrine and then had me try a beta blocker, pindolol.  Neither one helped.  Midodrine in particular made me feel jumpy and tense.

All that said I probably should explore the dysautonomia a bit more...just not sure I know of a doctor who would have expertise.

[MichelleP_3811]

My heart rate can get into the 130s upon walking up the stairs but I don't get the weakness like you do.  It sounds like you may have some sort if inappropriate sinus tachycardia going on.  You say you had a positive tilt table test.  Have you checked into Dysautonomia?  If not you may want to check it out and see if this is your main issue.  But I agree that building up your cardiovascular stamina will help.  I had avnrt that would cause my heart to get caught in a rapid beat well into the 200s.  I had it most my life but was never one for exercising until I started to get the episodes of fast beat almost weekly.  I started doing cardio 40 minutes everyday  and the difference in how I was really almost unable to tolerate the anvrt before I started to do cardio to after I started exercising and found I could almost function normal with a beat in the 200s was  amazing to me.  So there is some truth to what your doctor recommended.   In general the beat you are experiencing should not cause any undue harm to your heart especially since it was deemed healthy but do check out dysautomomia because if you do indeed have that there are steps you can take to try and control your symptoms.  I do hope you are able to get a handle on this and feel better soon.  Take care.