The Relationship Between Hemodynamic Responses During Head-Up Tilt Testing and Parameters of Infection in Post-COVID Syndrome, Chronic Fatigue Syndrome, and Late-Stage Lyme Disease. — CFSMEATLAS
The Relationship Between Hemodynamic Responses During Head-Up Tilt Testing and Parameters of Infection in Post-COVID Syndrome, Chronic Fatigue Syndrome, and Late-Stage Lyme Disease.
Milovanovic, Branislav, Markovic, Nikola, Petrovic, Masa et al. · Viruses · 2025 · DOI
Quick Summary
This study examined 1036 patients with post-COVID syndrome, chronic fatigue syndrome, and Lyme disease to understand why they experience dizziness and fainting when standing up. Researchers performed tilt-table tests (where patients lie on a table that tilts upward) and checked for signs of past or ongoing infections through blood tests. They found that patients with evidence of multiple past infections were more likely to have abnormal responses during the tilt test, suggesting that lingering effects from infections may affect the nervous system's ability to control blood pressure and heart rate.
Why It Matters
For ME/CFS patients, this study provides evidence that autonomic dysfunction—a hallmark symptom causing orthostatic intolerance and syncope—may be linked to lingering effects of multiple infections. Understanding this connection could lead to better diagnostic approaches and inform treatment strategies targeting both immune and autonomic components of the disease. The work supports the growing recognition that ME/CFS is a post-infectious condition with a biological basis.
Observed Findings
Lyme disease patients showed the highest prevalence of abnormal tilt test responses and orthostatic hypotension/syncope compared to other groups.
50-65% of PCS and Lyme disease patients were IgM-positive for at least one microorganism, with >10% positive for three or more pathogens.
Antibody status to HSV-1, HHV-6, Coxiella burnetii, Toxoplasma gondii, and Borrelia spp. independently predicted abnormal tilt test outcomes.
Negative IgG antibodies to HSV-1 and VZV were associated with Lyme disease group membership.
Inferred Conclusions
ANS dysfunction in post-infectious syndromes may be driven or perpetuated by persistent or prior infections rather than being solely a direct effect of the acute infection.
Multiple simultaneous or sequential infections may have a cumulative effect on autonomic regulation.
Integrative diagnostic approaches combining hemodynamic testing with comprehensive serological screening may improve identification and stratification of post-infectious syndrome patients.
Remaining Questions
Does the presence of multiple antibodies indicate truly persistent infection, reactivation, or simply prior exposure—and does this distinction affect disease pathophysiology?
Are the observed antibodies directly causing ANS dysfunction, or are they markers of a broader dysregulation of immune and autonomic systems?
What This Study Does Not Prove
This study demonstrates association, not causation—it shows that infection markers correlate with autonomic dysfunction but does not prove that infections directly cause it. Serological positivity (antibody presence) indicates past exposure, not necessarily active or persistent infection driving current symptoms. The cross-sectional design cannot establish whether antibody status precedes, accompanies, or follows the development of ANS dysfunction.
Tags
Symptom:Orthostatic IntoleranceFatigue
Biomarker:AutoantibodiesBlood Biomarker
Phenotype:Infection-TriggeredLong COVID Overlap
Method Flag:PEM Not DefinedNo ControlsMixed Cohort