stress test as evidence against PSVT

[High_Anxiety]

My E.P. was interested to know about my recent EKG stress test, during which I reached a HR of 170BPM after 10 minutes on treadmill, despite being on Atenolol.

His question to me was: "Do you feel like you could have gone on longer?"

I said "yes." I absolutely could have gone on a few more minutes. I only stopped because the nurse said once I reached my "target" HR, they would have all the information they needed. So I stopped.

I think the E.P. was pointing out that a stress test during which I achieved a sinus tachycardia of 180-200 BPM would prove that my heart is capable of beating that fast while not being in PSVT, which might be evidence that simply have a very high Sinus Rate potential, and not  a true PSVT.

Maybe I should have another stress test to provide this information. I know I could easily get my rate up anther 10+ BPM.

[Bromley]

I believe the thinking about blockage of coronaries is that this can be a slow progression over time, with the first indications of ischemia likely to start occuring when a person exercises.


I believe the strength of the stress test depends to some extent on the person exercising at a maximum.  This might be because the statistical correlation between the test results and the presence of ischemia depend on the test to be performed under a known condition:  maximum stress, even if the duration of the test is short.  If there are reversible indications of ischemia on the ecg or by way of symptoms, while exercising  at a maximum, then the likelihood of finding ischemia is quite high.  

Recently, I failed one stress test myself because of ST depression: in this case I exercised until exhaustion, much above my predicted maximum. The second test did showed ST depression, but not to a level considered diagnostic of ischemia. In this case, I was asked whether I exercised to a maximum, and had to say no. The nurse stopped the test somewhere near my predicted maximum, but I could have done more.

Does the second test result dilute the first one? No. In the first test we see the very first indications of a partial blockage. A more or less early wake up call to make lifestyle improvements. Statistically, it is significant and undiluted by the second result because the st depression met the diagnostic criteria while attempting to exercise at a maximum.

[Artaud]

I still was never that attracted to any monitor I used. LOL.

When they talk about maximal heart rates, often it is as a goal for a stress test. I think, with age, that the blood supply to the heart can, in some individuals, significantly diminish, in others, due to issues with loss of elasticity or tone of the coronary arteries, diminish somewhat. As the heart is placed under stress, it is important to keep sufficient blood flow to it. Obviously, as we age, the theoretical Max, for testing purposes, must diminish so as not to over stress the heart. Other changes in the heart naturally hinder higher heart rates as we age.

http://www.nia.nih.gov/health/publication/aging-hearts-and-arteries/chapter-2-aging-heart



Below, from another source.

"Risk Factors and Causes of SVT

Although SVT episodes can occur in anyone, there are certain factors that may increase an individual’s risk. Examples of these risk factors include:

Excessive caffeine or alcohol use, History of tobacco use, Illicit drug use, Extreme psychological stress and anxiety, Hyperthyroidism, Low potassium and magnesium levels, Family history of tachycardia, Structural abnormalities of the heart, Adverse reactions from certain pharmacologic agents (ie, antihistamines, theophylline, cough and cold preparations, appetite suppressants ), Certain medical conditions (eg, cardiovascular disease, long-term respiratory disease, diabetes, anemia, cancer)"

This is why it is imperative that patients are properly evaluated and followed up with by a physician.

Be well.

[tom_h]

"I think the E.P. was pointing out that a stress test during which I achieved a sinus tachycardia of 180-200 BPM would prove that my heart is capable of beating that fast while not being in PSVT, which might be evidence that simply have a very high Sinus Rate potential, and not  a true PSVT. "

Years ago, in my competitive skating and cycling days, I could get my sinus rate into the low 200's during extreme physical output.  The trainers would administer maximum O2 uptake tests by putting us on cycling rollers, sort of a treadmill for bicycles, and we'd pedal like our lives depended on it.  We were wired up for EKG, and breathing through a full face mask.  I could hit 210bpm, and still be in sinus rhythm.  No problems.  However,  I could get on the rollers the next day, just to warm my legs up, and I'd jump into SVT.  It was maddening!  So for me, my top end HR had no bearing on whether or not I'd experience SVT. One other thing. A sinus HR of 200 felt completely different than an SVT event of the same rate.  I knew if I dropped into SVT during a race or a workout.  It just different...

[Artaud]

There are indicators for some disorders, and downright explicit and no mistaking it proof of others. I remember being at the E.R. one time, and I was discussing some aspect of my rhythm. The doctor said that one thing some other doctors forget is to "Look at the Patient". It's easiest to see in Bradycardia. It's held that rhythms below 60 BPM are Bradycardic, but there are no clear cut rules for the significance. Some people manifesting a resting pulse of 50 will need a pacemaker, others manifesting a resting pulse of 45 are quite normal, it is their normal pulse. Their heart's may be moving a larger volume of blood with each beat.

Physicians are to try their best to do no harm. Oft times, it requires a conservative approach. After my thyroid was removed, I was started on synthroid. There is a formula for determining the initial dose to bring it near the expected level. Yet my doctor used the "Start low and go slow" approach. I never thought I was going to make it to the desired level, each change was only occurring every two months, and they were slight changes. My dose now is slightly higher than what was calculated by the formula I mentioned above, but the doctor didn't want to cause harm by just thrusting the full dose on me.

Hang in there. (Oh, did you have thyroid levels checked? Just curious).

[MichelleP_3811]

I can only go by my own experience but will tell you a few things if it helps you to look at your issue better.  I had avnrt which means there was an extra muscle fiber leading into my avnode that sometimes would get caught in a loop and cause my heart to beat crazy fast.  During those episodes I would get severely short of breath and feel as though I would pass out.  The thing to note is that the beat felt manic.  Crazy out of control manic.  I have also had sinus tachycardia.  This is usually after a night of heavy drinking and becoming dehydrated.  The beat feels fast but normal. It can go into the range of 160s upon moving around and would be around 130 just sitting.   I am short of breath but not severe.  I also have exercised to the point of reaching a rate of 180. Again being at that high rate still did not feel crazy manic.  Granted the rates during sinus tachycardia and exercise did not reach the speed my svt did but I just felt a clear difference in the way the beat felt between the three.  And maybe that is what the EP was trying to get at.  When you feel your heart beating too fast does it feel different than how you feel when you exercise.  Can you still function to some degree.  There is no way I could continue on a treadmill if I was in svt but I could still go on while in sinus tachycardia whether from dehydration or exercise.  Though that may not be what he was getting at I think you posting this made me realize how much different I feel between the different settings.  In SVT I felt manic and severely short of breath.  In Sinus tachycardia from dehydration I felt short of breath with a normal fast beat.  With high rates during exercise I feel a fast beat but I am only short of breath while exercising.  The second I stop the shortness of breath stops as well.  So maybe rather than focusing on the high rate focus on the other symptoms to see if that leads to a better understanding of what is going on.  I will say one last thing.  In none of them did I really have adrenaline from stress as a factor.  Adrenaline for me gets my ectopics going.  So try to take stock in how the adrenaline from stress feels and any additional symptoms it might bring to the table compared to when you are in a fast beat without the adrenaline.  The point being the more you can isolate and compartmentalize things the clearer the picture may become for you.  It can still be hard to pin down exactly what is going on but you are the one in your body so you really are the best one to distinguish any differences in what you feel.  

On another note the ep could also have been trying to reassure you that the rate you feel when you are feeling tachycardia for no reason is the same rate you achieve during exercise and your heart handles it well so try and look at it that way.  Your heart can handle the rate even for 20 minutes at a time.  So hopefully that kind of knowledge will help ease your mind about what is going on.  Hope that helps.