POTS - definition, diagnosis and symptoms

[Utsikt]

You probably know this but my understanding is that POT is postural orthostatic tachycardia, it occurs in healthy people too. You stand and your HR jumps up and stay up by 20bpm from resting for over 10 minutes.

I thought tachycardia referred to a resting HR above 100 bpm? So POT would be resting HR > 100 bpm while standing but not lying down?

POTS is that you have a suite of symptoms along with POT.
Clinicians are confident a patient has POTS when they use a treatment to fix the POT (midodrine, mestinon) and all the other symptoms (fatigue, brain fog, etc) get significantly better or completely resolve.

Is there any reliable evidence that the HR is directly tied to symptoms? Do you have any examples?

And do you have any evidence from properly controlled trials wrt the treatments?

Because POT can just exist in people without symptoms, it is possible that you just happen to have POT and it doesn't bother, then you get ME/CFS or another syndrome with a suite of symptoms that means you can now meet a POTS diagnosis. Makes it quite messy though, as the average person isn't tested for POT until they show symptoms of the syndrome.

This makes no sense to me, and just illustrates how useless the concept of POTS is. Why would you centre the syndrome around POT when POT can frequently occur without the other symptoms?

 

[ChronicallyOverIt]

Sorry, only POTS is.

POTS implies that there exists a syndrome where tachycardia upon standing is key to the syndrome. That doesn’t seem to be the case, and regardless it’s pure speculation.

OI is just «intolerance to not being horisontal». The use of HR to measure OI is flawed for much of the same reasons as for POTS - HR might not be relevant at all.

If you can’t call it Postural orthostatic tachycardia syndrome what do you call it? All POTS patients have the same symptom of heart rate staying abnormally elevated after standing, that not a syndrome?

Syndrome: a group of symptoms which consistently occur together, or a condition characterized by a set of associated symptoms.

 

[ChronicallyOverIt]

I thought tachycardia referred to a resting HR above 100 bpm? So POT would be resting HR > 100 bpm while standing but not lying down?

That is not POTS. If that was the criteria everyone would have POTS. The postural and orthostatic part you are completely ignoring.

It’s defined a jump in 30 BPM sustained over 10 minutes when going from lying to standing. Key is sustained.

 

[Utsikt]

If you can’t call it Postural orthostatic tachycardia syndrome what do you call it?

Call it what it is: OI. That’s the important part, that you get unwell when not horisontal.

All POTS patients have the same symptom of heart rate staying abnormally elevated after standing,

Yes, because POTS has been defined that way. That argument is circular.

that not a syndrome?

There is nothing that indicated that >30 bpm HR increase when standing is the sensible defining or diagnostic feature when trying to pick out people that feel unwell then standing/sitting and where it might be for the same reasons. There is also nothing to indicate that lowering the HR of the patient helps with their OI.

 

[Utsikt]

That is not POTS. If that was the criteria everyone would have POTS.

I was responding to a question about POT there, not POTS.

The postural and orthostatic part you are completely ignoring.

Where?

 

[ChronicallyOverIt]

Call it what it is: OI. That’s the important part, that you get unwell when not horisontal.

Yes, because POTS has been defined that way. That argument is circular.

POTS is under OI but it is with the increase of BPM. OI does not have to have the increase in BPM. Again it’s a syndrome since it has a collection of distinct symptoms, one of those being that increase in BPM.

 

[Eddie]

Call it what it is: OI. That’s the important part, that you get unwell when not horisontal.

There is nothing that indicated that >30 bpm HR increase when standing is the sensible defining or diagnostic feature when trying to pick out people that feel unwell then standing/sitting and where it might be for the same reasons. There is also nothing to indicate that lowering the HR of the patient helps with their OI.

OI encompasses any symptoms you get when upright. Fainting upon immediate standing or some sort of localized pain when upright is by definition OI.

But I think we agree that when we refer to the syndrome of POTS we are not referring to those things. We are referring to things like getting more dizzy over time with standing, having hands and feet go red, being intolerant of being upright in heat, "brain fog" when upright, vision changes and are being more likely to have an excessive increase in heart rate when standing.

I think it is warranted to have some sort of category to include people with these kinds of symptoms, instead of a simply broad category of OI. Heart rate and blood pressure must be relevant to what happens when standing upright so producing a group that has a similar HR and BP responses, at worst, has the same probability of members of a group having the same pathology as the larger OI group. Even if heart rate plays no impact on the symptoms (which I think is unlikely for many reasons), selecting based on these criteria only means you have group with OI that also has a similar heart rate and blood pressure response when standing. I think this would only help reduce some of the variables when looking at people with OI.

I see it similar to selection of ME/CFS patients. It is perfectly reasonable to only include post-infectious ME/CFS to try and produce a group that is more likely to have the same underlying process. I don't see how restricting to post-infectious ME/CFS could produce a group that is more varied in the cause of symptoms than the broadest category of ME/CFS alone.

 

[Eddie]

I think it is very much up for debate if an individual with an excessive increase in heart rate on standing is more likely to have OI. There are clearly people with no OI that can have large increases in HR when standing. But the important question is if we randomly took a group of people with the symptoms associated with POTS that had not yet done a TT and compared the HR increases to controls without OI. If it is the case that people with the symptoms associated with POTS are more likely to have a heart rate increase on standing than controls, that could justify using HR to categorize patients even if 30BPM isn't the best HR to use.

Also I am interested to hear your thoughts on this Utsilk. Small sample size but it is a double-blinded, placebo-controlled, crossover trial. https://www.sciencedirect.com/science/article/pii/S0735109720381316

 

[Jonathan Edwards]

POTS is that you have a suite of symptoms along with POT.
Clinicians are confident a patient has POTS when they use a treatment to fix the POT (midodrine, mestinon) and all the other symptoms (fatigue, brain fog, etc) get significantly better or completely resolve.

Clinicians may well be confident @MelbME, but clinicians are confident of all sorts of things - it took me decades to shake off that confidence, which you are trained to demonstrate as part of the 'art of medicine'. How can a clinician possibly know that it was the treatment that fixed all the symptoms? This is why we have trials. Otherwise we have to accept that physios with their GET and psychologists with their CBT know that they have fixed all the symptoms (because the patient finds it easier to say that than to face a disappointed and moody professional.)

And a high proportion of patients who get a diagnosis of POTS also get a diagnosis of ME or Lyme, so which bit is which? As far as I can see it is make-believe. I may be wrong but my first mentor was heavily into the hypermobility make-believe and I have seen how elaborate it gets over the years.

 

[Jonathan Edwards]

If you can’t call it Postural orthostatic tachycardia syndrome what do you call it? All POTS patients have the same symptom of heart rate staying abnormally elevated after standing, that not a syndrome?

But that isn't the way the term is used. POTS is used to include all sorts of other things like fatigue. If it is used simply to mean POT + OI that isn't a useful syndrome concept because POT occurs most often in normal people without OI (probably fifty times as many as those with OI). The evidence for the POT being the cause of OI symptoms is very unclear.

POT may well respond to beta blockers in the sense of reducing heart rate and for many people that may make them feel better because tachycardia is in itself quite unpleasant but the concept of POTS simply confuses everything.

 

[EndME]

I cannot comment on POTS in general and I find it possible that there may be instances where it has its use (for example there might be a different "group" of doctors outside of the Lyme/ME/CFS/Long-Covid "communities" where POTS is used in a different context even though the article at the bottom of the page suggests this needn't be the case).*

However, I do think that there is a problem more specifically within the ME/CFS sphere (including Long-Covid, Lyme ect doctors and organisations in this field) for POTS. In this sphere POTS is often used to synonymously to describe the orthostatic problems that people with ME/CFS describe. However, there is some strong evidence (that has been discussed on this forum at length) that suggests that the orthostatic problems in ME/CFS are in no way described by POT. In short: Take a person with ME/CFS that describes having significant OI and take a matched healthy control. If you run a tilt table test on them, there is strong evidence that suggests that the results will be exactly the same or more specifically that you cannot tell them apart on the basis of the results, i.e. POT doesn't characterise ME/CFS status nor the OI experienced. This doesn't just apply to the individual but as far as I can see there isn't evidence to suggest that there would be significant group differences in a well controlled study. That is compounded with the very significant problem of very low rates of reproducibility in this field, in part because POT can be affected by many things.

On the other side there have been some studies in the ME/CFS field which suggest POT does carry significance, but I think those studies have almost all been of a very poor standard and with the above strong evidence probably don't count for anything. There is a part of the POTS field that is very much just the same low quality memes we see in ME/CFS: One year POTS is caused by GPCR-aab, the next by microclots...

*There is quite a bit of general POTS research that suggests that picking out POT specifically is rather arbitrary, this is well known and documented in the field and people have tried establishing other things such as the MALMÖ symptom burden score. Why they have specifically hung onto POT isn't quite clear to me, maybe there has also been some high quality POTS research somewhere along the line and maybe it is justified outside of the "ME/CFS field", but it doesn't seem to help in the context of ME/CFS as far as I can see.

As always I find the following piece a great reference: https://mecfsscience.org/the-problems-with-pots/. The other side of the medallion is that a POTS researcher will say: There is no evidence to suggest that PEM characterises the symptoms experienced by people with ME/CFS.

 

[Utsikt]

POTS is under OI but it is with the increase of BPM. OI does not have to have the increase in BPM. Again it’s a syndrome since it has a collection of distinct symptoms, one of those being that increase in BPM.

There are plenty of people that have increased HR without OI, and that have OI without increased HR.

The problem with POTS is that they put the cart before the horse. As far as I have seen, nobody has put up any convincing argument for why HR is central.

I think it is warranted to have some sort of category to include people with these kinds of symptoms, instead of a simply broad category of OI.

That might be, but POTS is not it.

If it is the case that people with the symptoms associated with POTS are more likely to have a heart rate increase on standing than controls, that could justify using HR to categorize patients even if 30BPM isn't the best HR to use.

I disagree. If it’s just an increased probability it’s far too loosely connected.

 

[Utsikt]

Also I am interested to hear your thoughts on this Utsilk. Small sample size but it is a double-blinded, placebo-controlled, crossover trial. https://www.sciencedirect.com/science/article/pii/S0735109720381316

Most patients didn’t have a HR increase of >30.
Blinding was broken for many patients.
Most QoL outcomes were a bust.

Not at all convincing.

Edit: thread here: https://www.s4me.info/threads/rando...h-hyperadrenergic-pots-2021-taub-et-al.19202/

 

[Eddie]

That might be, but POTS is not it.

Why not? We don't think ME/CFS has anything to do with inflammation of the spinal chord and yet it is a fine label.

I disagree. If it’s just an increased probability it’s far too loosely connected.

It depends on how much they are connected. An increased probability suggests that heart rate is in some way connected to the symptoms of POTS. It doesn't mean it is the cause, it could be a risk factor, a different downstream effect from the same cause or a response by the body to try and address a problem. But if in fact there is a connection between having the symptoms associated with POTS and a higher probability of HR increase that can justify including it in the syndrome of POTS along with the other symptoms.

These criteria are not attempting proving to prove cause and effect. It is more concerned about how best to group people together to make testing treatments, running studies, finding people with similar issues etc. easier as we are with the group called ME/CFS. In ME/CFS we are perfectly fine with including this like headache, unrefreshing sleep and OI as part of the diagnostic criteria when having ME/CFS only increases the probability of having these symptoms.

 

[Eddie]

However, there is some strong evidence (that has been discussed on this forum at length) that suggests that the orthostatic problems in ME/CFS are in no way described by POT. In short: Take a person with ME/CFS that describes having significant OI and take a matched healthy control. If you run a tilt table test on them, there is strong evidence that suggests that the results will be exactly the same or more specifically that you cannot tell them apart on the basis of the results, i.e. POT doesn't characterize ME/CFS status nor the OI experienced.

I think we can agree that it doesn't characterize the OI many people with ME/CFS experience. But it can still be the case that having ME/CFS increases the chances of having POTS like OI issues. In the summary of the ME/CFS v controls for POTS the ME/CFS patients had 2/3rd more POT than controls. I wouldn't characterize that have being unable to tell them apart on the basis of results. Instead you are more likely to have POTS but it is certainly not universal.

It would also be interesting to look at what proportion of pwME have the symptoms associated with the syndrome of POTS without the heart rate increase. What kind of OI symptoms do people with ME/CFS experience that are in no way related to the OI symptoms associated with POTS?

 

[EndME]

I think we can agree that it doesn't characterize the OI many people with ME/CFS experience.

Good.

But it can still be the case that having ME/CFS increases the chances of having POTS like OI issues.

Yes, but I don't think we've even seen evidence for that or and good evidence to suggest how large the increase is. You should not forget how low the standards in this field are. You will struggle finding well controlled studies. They hardly exist! ME/CFS might have no impact when studies aren't even gender, age or BMI matched, not even to speak of being activity matched which of course might be affecting such results.

In the summary of the ME/CFS v controls for POTS the ME/CFS patients had 2/3rd more POT than controls. I wouldn't characterize that have being unable to tell them apart on the basis of results. Instead you are more likely to have POTS but it is certainly not universal.

And as you can see that data is driven by all sorts of biases, that's why you sometimes have a 70% prevalence and sometimes a 8% prevalence. These are not controlled studies in a meaningful way of the word. I'm also unsure whether all the data actually tells you something about POT in the same way. For example the Walitt data is a reference to "the frequencies of excessive orthostatic tachycardia at 10 minutes" rather than "prevalence of POT" and of course a lot of the data will be driven by a strong selection bias. I have forgotten what the actual data of Walitt et al looked like and it seems worthy of a closer look. But I don't think one should make conclusions before having good data. I may be misremembering but I do think there was a time where I did have a closer look at this data in relation to OI symptoms being reported and there being a non-relationship but I could be wrong. It would seem useful if someone would check this properly.

It would also be interesting to look at what proportion of pwME have the symptoms associated with the syndrome of POTS without the heart rate increase. What kind of OI symptoms do people with ME/CFS experience that are in no way related to the OI symptoms associated with POTS?

At least for the above mentioned study there should be data on this. The problem is that the list of symptoms associated with the syndrome of POTS overlaps significantly with the criteria of ME/CFS so things become a meaningless check-list quite quickly and then there's people in the field of POTS for whom symptoms of POTS as meant with the MALMÖ score overlap even more heavily with ME/CFS than for others. So these arguments become circular very quickly. If you'd use the Walitt study and if you'd use the same data as above you'd then have that 63% of people have a whole check-list of symptoms associated with the syndrome of POTS without the heart rate increase. That is more compelling than the opposite claims brought forward.

What kind of OI symptoms do people with ME/CFS experience that are in no way related to the OI symptoms associated with POTS?

The list of symptoms associated with POTS is long so I don't think these are the right kind of questions. What would one consider the OI part of that list? The ones that aren't brainfog, fatigue insomnia ect, but rather dizziness, presyncope, dyspnoea and palpatations? People with hyperthyroidism and also hypothyroidism also experience symptoms that are listed as part of "symptoms associated with POTS" but that doesn't mean POTS is of relevance there and of course the problems coming up in the lists are caused by exactly the opposite things. I think a fundamental difference is that people with ME/CFS generally describe a problem with being upright rather than specific issues like dizziness, presyncope or dyspnoea. But I think what you're asking here is pretty much why POTS has to be abandoned in this context in the first place. People have been using the label of POTS instead of curiously investigated the actual problems, because they like an "objective measurement" even if we all know that it isn't one.

I think most evidence I've seen points fairly in the opposite direction of POTS being of relevance and that it's best to start anew but I'd be happy if someone constructs a convincing argument on why the same path that hasn't lead anyway until now should keep on being followed.

 

[Utsikt]

Why not? We don't think ME/CFS has anything to do with inflammation of the spinal chord and yet it is a fine label.

ME is not an appropriate label for the disease for the reasons you mention.

«ME/CFS» does not refer to the individual letters. See Jonathan Edward’s piece about that here:

https://www.s4me.info/threads/the-concept-of-me-cfs-2024-edwards.40979/

 

[Utsikt]

These criteria are not attempting proving to prove cause and effect.

Yes, they are when the name is POTS, they include >30 bpm increase in the criteria, and treatments are initiated purely based on their ability to lower HR.

 

[Eddie]

Yes, they are when the name is POTS, they include >30 bpm increase in the criteria, and treatments are initiated purely based on their ability to lower HR.

We are discussing POTS not POT. Clearly the tachycardia is associated with the syndrome but I don't hold the position that the tachycardia causes the various symptoms. Some may take that position, but not me. I don't think we are in a position to know what role the elevation in rate has other than it can be uncomfortable.

Your position seems to be that POTS is a unhelpful category that should be done away with. I am simply arguing that there is a collection of symptoms that includes tachycardia on standing which should be given a name. I think this category can have some overlap with collections of symptoms like ME/CFS. However, I think a separate category is warranted because symptoms like acrocyanosis and a heart rate that continues to rise with standing are not present in all with ME/CFS. There are also people with POTS that do not have PEM and I think we can do better than lumping them these individuals into a general category of OI.

I just looked at the old tilt table studies and they are all over the place. Still if we assume that 5 or 10% of the healthy population has a HR increase on standing of 30 bpm, if say 50% of people with POTS like symptoms (OI + some extra stuff) had that same heart increase that still means that it is somehow related. I don't know what that number actually is, but it is almost certainly higher than 5 or 10%.

Before I developed OI symptoms, I am convinced that my heart rate did not go up 50 bpm with standing. I was an athletic person who often tracked HR and did not notice such an increase. Of course I never did a TTT but I think I would have noticed some change on standing if my HR had always been like it is now. Perhaps the development of my OI symptoms and the HR increase are unrelated and just happened at the same time, but I am sure you can understand why I would be skeptical having experienced that.

Heart rate and blood pressure are going to play some role in happens when we stand. The body has to compensate for the effects of gravity. I just don't see why having a category of people that experience OI symptoms and have HR increases is a issue. It provides an opportunity to try and figure out why the heart rate is going up and whether lowering HR is useful.

 

[Jonathan Edwards]

Your position seems to be that POTS is a unhelpful category that should be done away with. I am simply arguing that there is a collection of symptoms that includes tachycardia on standing which should be given a name.

I can see your argument here but for me it is a pragmatic issue that in this case fails to be convincing as much because of muddled clinical practice and advice as biology.

Take the situation for Reiter's syndrome. We have a cluster of overlapping features and categories in this area:


Features:
synovitis of a few joints
keratoderma rash
conjunctivitis
urethritis
psoriasis
spondylitis
nail dystrophy
STI
dysentery
HLA-B27

Categories:
Reiter's syndrome
Post-infective arthritis
Spondarthritis
Autoinflammatory disease
Inflammatory arthritis
Seronegative oligoarthritis
psoriatic arthritis

We talk about all of these without any need for categories to be mutually exclusive. Some of them are (psoriasis and keratoderma). Others are overlapping layers.

POTS might be a useful layer, picking out persistent fatigue and tachycardia-associated OI without PEM. But in the above lists there are terms we do not need or use - nail dystrophy syndrome, keratoderma arthritis... because, despite covering associations just like the others, they are not the most helpful ways to stratify.

My understanding is that there are people with POT associated with severe OI who do not have PEM but my impression is that they tend not to have that much persistent fatigue. I know of someone like this. I also suspect that almost all of these are women (as in the study). I do not know the history but it would make sense if the association of POT and severe OI on its own was called POTS. The trouble comes when the usual band of private physicians start claiming that everything is associated with everything and that people with POTS have persistent fatigue and of course are hypermobile and have mast cell activation syndrome. Most of these people seem to turn out to have ME/CFS with OI for other reasons, but that is probably selection bias.

I am doubtful that there is enough of an association between POT/OI and all the other stuff to justify the wider use of POTS. And the wider use is being invoked because claims are made for changes in broader QOL issues.

I think there are three concepts here POT, POT/OI and POTS. POT/OI is of importance but I am not convinced the others are helpful.