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Sad news: PC-POTS Update Results from the Phase 2 ALPHA study of efgartigimod in post-COVID-19-mediated postural orthostatic tachycardia syndrome (PC-POTS) show that treated patients had no clinically meaningful improvement compared to placebo on the total Malmö POTS symptom (MaPS) score and...

Thanks!

Yes that is probably an issue and your own measurements show that very clearly: there seems to be a large inter-individual variability: one day you have increases with 45, other times only 11 bpm. Some argued that orthostatic tachycardia measurements during standing or tilt testing are a bit...

@Nightsong Do you know of any studies that measured the prevalence of POTS among OI patients? For example: clinics that report the % of POTS in the patients with OI that get referred to them. I found this one paper that says that only 19% of their OI patients fulfilled POTS criteria. Patients...

I think the conclusion is more that POT may not be relevant to the symptoms POTS patients experience. Orthostatic tachycardia seems to have a very weak relationship with orthostatic symptoms.

No did not work but thanks anyway. SNT Gatchaman kindly helped me out.

Yes unfortunately, they do not report how many students had more than 40 bpm HR changes as that would give an indication of the current threshold. They only report the median (20) range (-15 + 61) and 2.5% (-1) and 97.5% (48) quartiles and mention that 23% had a HR increase of more than 30 bpms...

Thanks, it all seems to point to the same researcher: Phillip A. Low at the Mayo Clinic. Phillip A. Low, M.D. - Doctors and Medical Staff - Mayo Clinic

Same finding here: 9 of the 15 controls (60%) had an HR increase that was higher than 30 bpm after 10 minute passive tilt table testing. With a 10 minute standing test, 5 (33%) met the POT criterium. They proposed to increase the HR cutoff to 37 bpm which resulted in a sensitivity of 40% and a...

I suspect that study forms the justification for the > 40 bpm threshold for children, even though it showed that 5% of healthy controls had a HR increase higher than 42 bpm. The study not included healthy controls but also more than 600 children who were referred with diagnoses of orthostatic...

This abstract from a German study did 10 repeated tests and found that it did not lead to stable results. Intra- and interindividual reproducibility of heart rate variations in the tilt-table test - PubMed (nih.gov)

Thanks to @SNT Gatchaman for helping me out. In the study they had a control group of 20 men and 21 women aged 20 to 50 years. For the control group they report that "between the second and third minute of tilt, HR increased by 20.1 ± 8.9 bpm in men versus 14.8 ± 8.1 bpm in women." So it seems...

Thanks but I actually meant the 1993 Schondorf-Low paper where POTS was first defined: Idiopathic postural orthostatic tachycardia syndrome An attenuated form of acute pandysautonomia? Ronald Schondorf, PhD, MD, and Phillip A. Low, MDAUTHORS INFO & AFFILIATIONS January 1993 issue 43 (1_part_1)...

Thanks for the useful references @Nightsong Found some other ones too: Orthostatic heart rate does not predict symptomatic burden in pediatric patients with chronic orthostatic intolerance - PubMed (nih.gov) Orthostatic intolerance without postural tachycardia: how much dysautonomia? -...

Thanks. Does anyone have access to this paper? Haven't been able to find it online.

Where does the idea that >30bpm increase during tilt testing is pathologic came from? Does anyone know how this threshold was justified or where it was first used?

There were 252 participants in this study of which 123 in the age group of 18-29 (where POTS diagnosis is common). They only did 5 instead of 10 minute testing but don't think that would impact the conclusion (one would expect the HR increase to be even higher with 10 minute testing). Half of...

There are more of these. Plan to write a blog post about it to summarize the main findings. Might have important implications for POTS and OI research in ME/CFS.

Think I've more or less found what I was looking for: Normal versus abnormal: What normative data tells us about the utility of heart rate in postural tachycardia - PubMed (nih.gov) The authors did 5 minute tilt table testing in a sample of the general population and found that POT was quite...

Looks like a highly problematic article, suggesting the opposite of what actually should be done to help patients. It refers to the Cochrane review (Larun et al.) to argue that GET is beneficial and to the PACE trial to argue that pacing is not (they suggest the term should be abandoned)...