POTS - definition, diagnosis and symptoms

[Utsikt]

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.

I’ll ask you this:

What’s the difference between these two patients:
1) OI, fatigue and dizziness when upright, HR increase of 20 bpm when upright
2) OI, fatigue and dizziness when upright, HR increase of 31 bpm when upright

Only the first patient fits the definition of POTS, but in my mind for all intents and purposes these patients are identical. There is no clinical justification that I know of for separating these two patients. Therefore, the concept of POTS is completely unjustified, and should be done away with.

 

[duncan]

A few years back I was in a well regarded ME/CFS study that required a four-day stay in-hospital. Among tests that included constant blood work and a lumbar puncture and a couple MRIs, every few hours I was asked to stand for ten minutes while they checked my HR and BP. They must have checked the latter two at least 20 times during my stay.

When I left I was told I most certainly had POTS. BTW, I am male.

A couple years prior to that, I was tested by a different well-known ME/CFS researcher/clinician. He said I had OI, but as I recall, he also had checked my HR and BP upon standing for ten minutes.

Somehow, somewhere along all these exams I came away with the sense that POTS was a subset of OI, and that OI was a common feature of ME/CFS - but not a pre-requisite - and POTS was simply a less common feature, but that neither was restricted to ME/CFS.

Perhaps the "S" in POTS is ME/CFS sequelae, or Lyme or whatever else symptoms that might make the "S" be misconstrued as integral to POTS.

But I have to agree that simply because we can apply a label to a set of symptoms, even making that label definitional, doesn't necessarily legitimize that set as a valid entity. Or the label.

Having said that, I once went to a cardio who identified my increase of HR and changes in BP whenever he checked me or when I shared those values from other clinicians, as part and parcel of white-coat syndrome. When I pointed out my POTS diagnosis, he shrugged it off.

I fired him. If I'm going to get slapped with dubious diagnostic labels, I will decide which ones.

 

[Peter T]

I have assumed, as with @duncan, that some degree of orthostatic intolerance is very common, or even ubiquitous, in ME/CFS. However we do not have a good way to reliably confirm its presence in milder forms. I suspect for a lot of milder ME/CFS OI of itself does not trigger obvious symptoms but that the amount of time upright contributes to any activity triggering PEM. I guess to measure this would require a complicated equation of activity, positioning and subjective reporting of symptoms.

I feel it would be useful to have a clearer idea of the full spread of orthostatic intolerance related symptoms in ME/CFS including heart rate and blood pressure. Which also raises the question of whether people meeting the diagnostic criteria of POTS have this as a co-morbid condition or as simply one end of the variation of orthostatic related symptoms that are part of ME/CFS. Presumably it would be interesting to see how people who meet the POTS criteria with ME/CFS compare to those who meet the criteria without ME/CFS.