Variability of postural orthostatic tachycardia in patients with myalgic encephalomyelitis and orthostatic intolerance
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Central nervous system dysfunction with myalgic encephalomyelitis (ME) has been suggested as the main cause of chronic fatigue syndrome. Fluctuation of the symptom severity and hierarchy is a characteristic feature in ME patients. The characteristics of the sympathetic activation may differ between the “good days” and “bad days” in them. Twenty-four ME patients with orthostatic intolerance underwent a conventional 10-min active standing test and echocardiography both on a “good day” and a “bad day”, defined according to the severity of their symptoms. The mean heart rate at rest was significantly higher on the “bad days” than on the “good days”. During the standing test on a “bad day”, 5 patients (21 %) failed to maintain an upright posture for 10 min, whereas on a “good day” all the 24 patients maintained it. Postural orthostatic tachycardia (POT) (increase in heart rate ≥30 beats/min) or severe POT (heart rate ≥120 beats/min) was observed on the “bad days” in 10 patients (43 %) who did not suffer from the severe tachycardia on the “good days”, suggesting the exaggerated sympathetic nervous activation. In contrast, POT did not occur or severe POT was attenuated on the “bad days” in 5 patients (21 %) who developed POT or severe POT on the “good days”, suggesting the impaired sympathetic activation. Echocardiography revealed significantly lower mean values of both the left ventricular end-diastolic diameter and stroke volume index on the “bad days” compared with the “good days”. In conclusion, in ME patients with orthostatic intolerance, the exaggerated activation of the sympathetic nervous system while standing appears to switch to the impaired sympathetic activation after the system is loaded with the additional accentuated stimuli associated with the preload reduction.
KeywordsChronic fatigue syndrome Myalgic encephalomyelitis Orthostatic intolerance Postural orthostatic tachycardia Sympathetic nervous system
I would like to thank Ms. Takako Miwa for her technical help. This work was supported in part by JSPS KAKENHI GRANT Number 15H00649.
Compliance with ethical standards
Conflict of interest
The author declares that there is no conflict of interest.
This study is in compliance with the standards in the 1964 Declaration of Helsinki and its later amendments.
- 4.Carruthers BM, van de Sande MI, DeMeirleir KL, Klimas NG, Broderick G, Mitchell T, Staines D, Powles ACP, Speight N, Vallings R, Bateman L, Baumgarten-Austrheim B, Bell DS, Carlo-Stella N, Chia J, Darragh A, Jo D, Lewis D, Light AR, Marshall-Gradisbik S, Mena I, Mikovits JA, Miwa K, Murovska M, Pall ML, Stevens S (2011) Myalgic encephalomyelitis: international consensus criteria. J Int Med 270:327–338CrossRefGoogle Scholar
- 15.Schiller NB, Shah PM, Crawford M, DeMaria A, Devereux R, Feigenbaum H, Gutgeseaell H, Reichek N, Sahn D, Schnittinger I, Silverman N, Tajik J, the American Society of Echocardiography, Committee on Standards, Subcommittee on Quantification of Two-Dimensional Echocardiograms (1989) Recommendations for the quantification of the left ventricle by two-dimensional echocardiography. J Am Soc Echocardiogr 2:358–367CrossRefPubMedGoogle Scholar