Orthostatic Intolerance in Long-Haul COVID after SARS-CoV-2: A Case-Control Comparison with Post-EBV and Insidious-Onset ME/CFS Patients 2022 Visser

Abstract
Background: As complaints of long-haul COVID patients are similar to those of ME/CFS patients and as orthostatic intolerance (OI) plays an important role in the COVID infection symptomatology, we compared 14 long-haul COVID patients with 14 ME/CFS patients with a post-viral Ebstein-Barr (EBV) onset and 14 ME/CFS patients with an insidious onset of the disease.

Methods: In all patients, OI analysis by history taking and OI assessed during a tilt test, as well as cerebral blood flow measurements by extracranial Doppler, and cardiac index measurements by suprasternal Doppler during the tilt test were obtained in all patients.

Results: Except for disease duration no differences were found in clinical characteristics. The prevalence of POTS was higher in the long-haul patients (100%) than in post-EBV (43%) and in insidious-onset (50%) patients (p = 0.0002). No differences between the three groups were present in the prevalence of OI, heart rate and blood pressure changes, changes in cerebral blood flow or in cardiac index during the tilt test.

Conclusion: OI symptomatology and objective abnormalities of OI (abnormal cerebral blood flow and cardiac index reduction during tilt testing) are comparable to those in ME/CFS patients. It indicates that long-haul COVID is essentially the same disease as ME/CFS.

https://www.mdpi.com/2227-9032/10/10/2058/htm

 

POTS being more common in the long Covid group is pretty unexpected. I wonder what could explain this?

Maybe Covid is causing POTS at a higher rate than other viruses for some reason. Anecodotally, I hear of a lot of long haulers with POTS or POTS-like symptoms.

 

There is a clear trend I can see in Long Covid of POTS being especially severe initially and improving over time for most, so this is not surprising. Now if only someone could learn something out of this, what changes over time instead of the usual single-points-in-time.

 

I'm not sure this is important. POTS is (somewhat arbitrarily) defined in adults as a sustained elevation of heart rate with orthostatic challenge of 30 bpm or more. Historically this was something objectively measurable to correlate with the patients' subjective symptoms of orthorstatic intolerance (dizziness, nausea, fainting etc). More recently this group has used Doppler ultrasound to show that the key cardiovascular finding is reduced cerebral blood flow — present in all POTS and the majority of ME and LC. They showed that this reduction in cerebral blood flow can be present in some even without significant HR and BP changes.

Spoiler: Sidebar

Additionally, there is a sex difference in the cardiovascular system: females are more likely to compensate against gravity via tachycardia, males by increased stroke volume and peripheral resistance. I think much of this is due to body size, with the extreme end of this being babies and small children (either sex) who can't increase stroke volume so push their heart rates very high when sick.

In this paper, they say:

Mean/SDs from their table 2.



Group 1 (LC) had a mean +34 HR delta. Group 2 (EBV-ME) had a mean +26 HR delta. Group 3 (insidious-ME) were +30.

So maybe no meaningful difference here. If there is a genuine difference (and to @rvallee's point) then maybe an explanation for LC being more "POTSy" relates to the associated vasculopathy and endothelial dysfunction, making vascular compensations harder to achieve and so relying on increased heart rate to boost cardiac output?

The LC patients were all <2 years duration, but the MEs were over 10 years longer, so some cardiovascular compensations may have developed.

 

This difference in POTS prevalence looks like it might have been down to length of illness. See this new paper from the same team:

Long-Haul COVID Patients: Prevalence of POTS Are Reduced but Cerebral Blood Flow Abnormalities Remain Abnormal with Longer Disease
https://www.s4me.info/threads/long-...ith-longer-disease-duration-2022-visse.30108/