ME/CFS Pathophysiology Investigated by Invasive Cardiopulmonary Exercise Testing and Autonomic Function Testing, 2023, Squires, ..Systrom et. al.

[voner]

ME/CFS Pathophysiology Investigated by Invasive Cardiopulmonary Exercise Testing and Autonomic Function Testing.

J. Squires 2, K. Wichmann Madsen 2, M.C. Stovall 2, S. Al-Zayer 2, W. Xiao 3, C.-J. Chang 3, P. Novak 1, D.M. Systrom 2,

https://doi.org/10.1164/ajrccm-conference.2023.207.1_MeetingAbstracts.A2996

This appears tp be a poster of an abtract of an upcoming session apparently at an American Thoracic Society meeting. There is a paywall and the abstract/poster is in image form only at this website. Pehaps someone else can find a way to get a pdf or something? Anyway, here is the website:

https://www.atsjournals.org/doi/epd...ce.2023.207.1_MeetingAbstracts.A2996?role=tab

 

[Hutan]

Conference abstract
Introduction: Mechanisms underlying exercise and orthostatic intolerance in myalgic encephalomyelitis/chronic
fatigue syndrome (ME/CFS) have been uncovered by invasive cardiopulmonary exercise testing (iCPET) and
autonomic function testing (AFT), but the relationships between the two are not known. This study aims to determine
if there is overlap of cardiovascular and respiratory pathophysiology in patients who have undergone both
tests.

Methods: Between January 2017 and April 2022, 62 patients were identified with a contemporary iCPET and
AFT. Key variables from the iCPET included peak oxygen uptake (pVO2), cardiac output (pQc), right atrial pressure
(pRAP), and systemic oxygen extraction (Ca-vOy/Hgb) at peak exercise. Key variables from the autonomic testing
included epidermal and sweat gland small fiber neurite density, electrochemical skin conductance, and change in
heart rate (AH) and end tidal carbon dioxide (AETCO2) from supine to upright during the tilt table test
(TTT).

Results: All 62 patients demonstrated preload failure (pRAP < 6.5mmHg). Of this group, 54 patients (87.1%) fulfilled NAM criteria for ME/CFS, with 32 testing positive (59.3%) for small fiber neuropathy (SFN) using either morphological and/or functional testing. Significant correlations were found between pVOg and both AH (r=-0.439. P<0.05) and AETCO, (r=0.474, P<0.05) during TTT. The same tilt table variables were found to be significantly correlated with pQc (r=-0.365, P<0.05 and r=0.351, P<0.05) from the iCPET. It should be noted that 8 of the ME/CFS SFN patients (25%) fulfilled diagnostic criteria for postural orthostatic tachycardia syndrome (POTS) based on the tilt table test.

Conclusion: Decreased oxygen uptake and cardiac output at peak exercise during iCPET correlated with a greater change in heart rate and ETCO from supine to upright during TTT. There appears to be significant overlap of cardiopulmonary pathophysiology in ME/CFS underlying exercise and orthostatic symptoms.

 

[Hutan]

The OMF webpage about this or related research by this team gives some information
e.g.

Two forms of heart failure identified in ME/CFS patients: preload failure and poor oxygen extraction.

Preload failure consistently shows a reduced max VO2 (~80%) (VO2 max: maximum amount of oxygen your body can utilize during exercise) along with a reduced right atrial pressure (RAP).

The poor oxygen extraction patients routinely also show a reduced max VO2 (~80%) and unexpectedly high pO2 in the mixed venous blood (pav O2).

The first form suggests an autonomic dysregulation and the second form may suggest either mitochondrial oxidation or peripheral shunting dysfunction.

 

[Sid]

Decreased oxygen uptake and cardiac output at peak exercise during iCPET correlated with a greater change in heart rate and ETCO from supine to upright during TTT.

Turned out to not be fear of standing after all!

 

[voner]

I am about 1/2 way through watching watching this video by Dr Systrom and I find it quite a quite good summary of his groups activities up to the point of the video which was in the late December 2022.

here is the info…

Recording:
Transcript: https://www.cdc.gov/me-cfs/pdfs/SEC-transcript-December-2022-508.pdf
Slideshow: https://www.cdc.gov/me-cfs/pdfs/sec-sy

I got some of the info from a @Tom Kindlon post in this thread on this forum:

https://www.s4me.info/threads/usa-c...ngagement-and-communication-calls.248/page-13

I am impressed. He really seems to be trying to dig deep and tease out subsets of patients and trial pharmecuticals on them. He discusses his thoughts on small fiber neuropathy, preload failure, mitochondrial myopathy, etc.

 

[voner]

Here is a screenshot from the talk Dr. Systrom gave in this video (unpublished data). He says that in the patients with “pre-load failure”, 87% met the qualification for ME/CFS and of those patients Patients that they sampled with a two location small fiber neuropathy biopsy (one tests the sweat gland neuropathy), almost 2/3 (62.9%) of those patients had small fiber autonomic neuropathy…