Chronotropic Incompetence

Posted by JohnWBurns @johnwburns, Aug 17, 2016

Basically a lofty sounding description of one’s heart not being able to perform under load anymore for various reasons.

“Chronotropic incompetence (CI), broadly defined as the inability of the heart to increase its rate commensurate with increased activity or demand, is common in patients with cardiovascular disease, produces exercise intolerance which impairs quality-of-life, and is an independent predictor of major adverse cardiovascular events and overall mortality. However, the importance of CI is under-appreciated and CI is often overlooked in clinical practice. This may be due partly due to multiple definitions, the confounding effects of aging, medications, and the need for formal exercise testing for definitive diagnosis. ”
I am dealing with this and the surprising thing is the relatively abrupt onset, at least in my case, in a matter of weeks at most. Suddenly your heart rate drops into the bradycardia range,

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@johnwburns Very interesting, I’ll look into that website.


So, what does this mean for you @johnwburns? Obviously, it is has a huge impact on your daily life, especially such an abrupt onset. What is the course of action? Can it be ameliorated?


So, what does this mean for you @johnwburns? Obviously, it is has a huge impact on your daily life, especially such an abrupt onset. What is the course of action? Can it be ameliorated?

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Thanks for asking. It hasn’t been 100% root caused yet. That will take a hotter and another stress test. Outside chance that its ischemic which would be easier to remedy. Per the cardiologist it can only be ameliorated via a pacemaker. The usual things can help slow deterioration, like weight loss and exercise. I am struggling with the notion of a pacemaker, more than I did with cancer, probably because the symptoms I have are sudden onset and have a clear impact, plain old worn out. Pacemaker implantation is routine these days but if there are complications, like infection, they need to go in. Like everything else at this stage, its a hangman’s choice.

Here is a prognosis breakdown:
The thing that I was trying to bring out by posting this topic is that the onset of symptoms can be sudden and easily mistaken for other issues. Apparently the node wears but functions until it reaches a tipping point. The process is driven by the natural pacemaker tissue becoming fibrotic.

I went for the checkup expecting bad news about my aortic stenosis or aneurysm. Both are fine but my left ventricular diastolic function is significantly compromised, Mayo grade 2/4, and then there’s this sick sinus deal. Goes to show, you won’t hear the one that get’s you. :). I had 2 echocardiograms in Portland at a major clinic and both missed the left ventricular issues. Mayo caught it. Why? Probably better equipment and a better doctor reading the results. Regional clinics? No thanks.



I should have added that one of the possible causes of chronotropic incompetence along with sick sinus syndrome is subclinical hypothyroidism. Thyroid disease, hypo or hyper, can mimic a lot of things and in this case, hypo should be excluded as part of the workup for bradycardia.

This is probably more technical than most people care for but better more detail than less is my perspective, rightly or wrongly.


I’ve had long covid for three years the small fiber neuropathy with dysautonomia variety. I diagnosed my own chronotropic incometence . The cardiologists were clueless because there is nothing wrong with my heart, its the autonomic nervous system which can’t tellmy heart to beat faster with exercise. It actually goes up to about 110, then drops to 75 and stays there until I pass out or stop. Its also called cardiac deceleration. It is easily picked up on a regular stress test, but they don’t normally monitor with a tracing the parameters that help to describe it. Just have blinders on looking for ischemia which does not exist. I don’t have bradycardia, just not enough increase as the muscles draw more oxygen out of the blood, it doesnt either get to the brain or the signal doesnt get from the brain to the heart and lungs. I also dont increase my breathing naturally, so get extremely short of breath and the pulse ox goes from 98 to 90%.
A separate short circuit is the circulation to the legs. Instead of the vessels to the leg muscles dilating, mine seem to constrict as my legs suddenly ‘ turn to jelly ‘ at a certain point in exercise.
As time goes on some of the nerves have seemed to heal and work almost normally. But I still reach a limit with the heart rate.

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