Orthostatic Intolerance in Adults Reporting Long COVID Symptoms Was Not Associated With Postural Orthostatic Tachycardia Syndrome, 2022, Ann Monaghan

In this observational cross-sectional study, we investigated predictors of orthostatic intolerance (OI) in adults reporting long COVID symptoms.

Participants underwent a 3-min active stand (AS) with Finapres® NOVA, followed by a 10-min unmedicated 70° head-up tilt test. Eighty-five participants were included (mean age 46 years, range 25–78; 74% women), of which 56 (66%) reported OI during AS (OIAS). OIAS seemed associated with female sex, more fatigue and depressive symptoms, and greater inability to perform activities of daily living (ADL), as well as a higher heart rate (HR) at the lowest systolic blood pressure (SBP) point before the first minute post-stand (mean HRnadir: 88 vs. 75 bpm, P = 0.004). In a regression model also including age, sex, fatigue, depression, ADL inability, and peak HR after the nadir SBP, HRnadir was the only OIAS predictor (OR = 1.09, 95% CI: 1.01–1.18, P = 0.027). Twenty-two (26%) participants had initial (iOH) and 5 (6%) classical (cOHAS) orthostatic hypotension, but neither correlated with OIAS.

Seventy-one participants proceeded to tilt, of which 28 (39%) had OI during tilt (OItilt). Of the 53 who had a 10-min tilt, 7 (13%) had an HR increase >30 bpm without cOHtilt (2 to HR > 120 bpm), but six did not report OItilt. In conclusion, OIAS was associated with a higher initial HR on AS, which after 1 min equalised with the non-OIAS group. Despite these initial orthostatic HR differences, POTS was infrequent (2%). ClinicalTrials.gov

https://www.frontiersin.org/articles/10.3389/fphys.2022.833650/full

 

I know I'm a broken record, but I still think its a mistake to indiscriminately refer to OI in ME and LC as POTS, when I don't think it is in many cases.

That's not to say it isn't sometimes POTS either. But there are other forms of OI, too, and the type in ME might be unique ME.

All it does is convince researchers to look at one thing again and again, often with the same results. (That may also be incurious researchers not trying to dig deeper for nuance, of course.)

My worry is that when studies show no association, like this, that it merely reaffirms that it's not an issue at all, rather than the alternative (that it's something else instead).

 

They should be considered syndromes of orthostatic intolerance, some are nonneurogenic, with no direct signs of autonomic nervous system disease.

Very difficult to find doctors that recognize the symptoms, let alone treat them.

 

Well said.

 

At one point there was no doubt I had POTS, the blood pressure and heart rate changes were really clear. Nowadays however I don't qualify for POTS, I just have OI and its completely different its based on how long I am upright its more a fatigue impact that gradually degrades my bodies ability to put blood pressure into my brain.

 

I think their protocol is decreasing the chances of positive tilt table test for both POTS, because they had that 5 minutes active stand test just before hand. Moreover, just before the TTT they only rest their patients 5 minutes

They said that 15% of their cohort is already on anti-hypertensive and 15% on beta- blockers. That is a problem.

It is unclear how many are working full time.

Edit to add: it would have been interesting to do a carotid doppler to compare with the work of Peter Rowe and colleagues.

 

Ten minutes seems like a rather short time frame for a tilt test.

I thought that at least 30 minutes was more usual? And I remember in the 1990s the recommendation from Dr. Rowe at Johns Hopkins was 45 minutes.

A 10 minute tilt table test might be long enough to find what they call "classic OH" in the paper (a drop in blood pressure very early on). But it will miss the delayed drop in blood pressure experienced by some ME/cfs patients (and probably in some subset of Long COVID patients).

I don't know if that delayed drop in blood pressure is still called neurally mediated hypotension, neurally mediated syncope, neurocardiogenic syncope, or what. But the symptoms are felt for quite a while before the severe drop in blood pressure (and possible faint). For me (two different tilt table tests) that drop in blood pressure happened somewhere in the 20 - 30 minute range.

I have only skimmed the paper, and I may be missing something important, but I wanted to post some thoughts. Maybe someone can add more to this.