Naschitz, Jochanan E, Slobodin, Gleb, Sharif, Dauod et al. · European journal of internal medicine · 2008 · DOI
This study found that ME/CFS and fibromyalgia, two conditions that seem similar on the surface, actually show different patterns on heart tests. People with ME/CFS had shorter QT intervals on their electrocardiogram (a measure of heart electrical activity) and had more dramatic blood pressure and heart rate changes during a tilting test compared to people with fibromyalgia. These differences suggest the two conditions may be distinct disorders rather than variants of the same illness.
This research suggests ME/CFS and fibromyalgia are pathophysiologically distinct disorders, which could support separate diagnostic and treatment approaches. Identifying objective cardiac biomarkers like shortened QTc could help clinicians differentiate between these overlapping conditions and inform future diagnostic criteria and research stratification.
This study does not prove that QTc shortening causes ME/CFS symptoms or that it is the primary pathological mechanism. The findings are correlational in a small, female-only cohort and cannot be generalized to male patients with ME/CFS or fibromyalgia, nor do they explain why these cardiac differences occur. The cross-sectional design prevents determination of whether these cardiac changes are present at disease onset or develop over time.
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
Naschitz, Jochanan E, Slobodin, Gleb, Sharif, Dauod, Fields, Madeline, Isseroff, Hillel, Sabo, Edmond, et al. (2008). Electrocardiographic QT interval and cardiovascular reactivity in fibromyalgia differ from chronic fatigue syndrome.. European journal of internal medicine. https://doi.org/10.1016/j.ejim.2007.08.003
BibTeX
@article{mecfsatlas-naschitz-2008-electrocardiographic-interval,
author = {Naschitz, Jochanan E and Slobodin, Gleb and Sharif, Dauod and Fields, Madeline and Isseroff, Hillel and Sabo, Edmond and Rosner, Itzhak},
title = {Electrocardiographic QT interval and cardiovascular reactivity in fibromyalgia differ from chronic fatigue syndrome.},
journal = {European journal of internal medicine},
year = {2008},
doi = {10.1016/j.ejim.2007.08.003},
note = {PubMed: 18395162},
url = {https://www.mecfsatlas.com/evidence/naschitz-2008-electrocardiographic-interval},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-25. https://www.mecfsatlas.com/evidence/naschitz-2008-electrocardiographic-interval
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