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?
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.
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.
I was responding to a question about POT there, not POTS.
Where?
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.
That might be, but POTS is not it.
I disagree. If it’s just an increased probability it’s far too loosely connected.
Most patients didn’t have a HR increase of >30.
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.
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.
Good.
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.
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.
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.
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.
ME is not an appropriate label for the disease for the reasons you mention.
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.
Yes fair enough. It might not be the best way to stratify, but given the relevance of HR to standing it seems at least reasonable and worth considering. I do think that there is some connection between POTS above average fatigue. But I don't know if that is a part of the syndrome or a result of having an elevated heart rate which itself can be tiring.