Langsjoen, P H, Langsjoen, P H, Folkers, K · The Clinical investigator · 1993 · DOI
This study looked at heart function in patients with chronic fatigue syndrome (ME/CFS) and compared them to patients with other heart conditions. Researchers found that many of these patients had a specific type of heart problem called diastolic dysfunction—where the heart doesn't relax properly between beats. When patients were given a supplement called CoQ10, their heart function improved and their symptoms got better.
Many ME/CFS patients experience cardiac symptoms including fatigue, chest pain, and palpitations that may relate to diastolic dysfunction—an energy-dependent cardiac process. This study suggests that CoQ10, which plays a critical role in cellular energy production, may improve both cardiac function and symptom severity in ME/CFS patients, potentially offering a therapeutic avenue for this under-treated symptom cluster.
This observational study cannot establish causation or prove that CoQ10 definitively improves diastolic function in ME/CFS; without a placebo control group, improvement could reflect natural history, placebo effect, or concurrent lifestyle changes. The study does not demonstrate that diastolic dysfunction is the primary cause of ME/CFS symptoms, only that it occurs frequently in patients with these symptoms. It also does not identify which ME/CFS patients would most benefit from CoQ10 or provide optimal dosing guidance.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Langsjoen, P H, Langsjoen, P H, & Folkers, K (1993). Isolated diastolic dysfunction of the myocardium and its response to CoQ10 treatment.. The Clinical investigator. https://doi.org/10.1007/BF00226856
BibTeX
@article{mecfsatlas-langsjoen-1993-isolated-diastolic,
author = {Langsjoen, P H and Langsjoen, P H and Folkers, K},
title = {Isolated diastolic dysfunction of the myocardium and its response to CoQ10 treatment.},
journal = {The Clinical investigator},
year = {1993},
doi = {10.1007/BF00226856},
note = {PubMed: 8241699},
url = {https://www.mecfsatlas.com/evidence/langsjoen-1993-isolated-diastolic},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-29. https://www.mecfsatlas.com/evidence/langsjoen-1993-isolated-diastolic
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