Impaired blood pressure variability in chronic fatigue syndrome--a potential biomarker.
BACKGROUND
Autonomic dysfunction is common in chronic fatigue syndrome (CFS). This study set out to derive an autonomic biomarker using a comprehensive assessment of heart rate and blood pressure variability.


METHODS
Heart rate and non-invasive continuous blood pressure measurements (task force monitor) at rest and on standing were performed in CFS (Fukuda n = 68) and matched controls (n = 68) to derive high frequency (HF; parasympathetic) and low frequency (LF; sympathetic) heart rate variability (HRV), systolic (SBPV) and diastolic (DBPV) blood pressure variability. Variables of significance were combined using receiver operator curves to explore the diagnostic utility of parameters particularly at rest.


RESULTS
At rest, LF-HRV (sympathetic) was significantly increased in CFS compared to controls, while parasympathetic markers were significantly reduced (P = 0.006). Total DBP spectral power was increased (P = 0.0003) across all domains, with a shift towards sympathetic and away from parasympathetic SBPV (P = 0.05). On standing, overall SBPV response was significantly reduced with reductions in both sympathetic and parasympathetic components of SBPV (all P < 0.0001). Change in LF-DBP and relative balance of LF/HF DBP on standing differed between CFS and controls (P < 0.0001). Using the 85% sensitivity levels, we determined a threshold for three chosen resting BPV parameters of LF DBP >3.185, rest HF DBP >0.86, rest total DBP >7.05. Achieving all of these differentiated between CFS and controls with 77% sensitivity and 53% specificity.


CONCLUSIONS
This study has shown that there are objectively measured abnormalities of blood pressure variability in CFS and that these abnormalities have the potential to be a bedside diagnostic tool.
UK NIHR Biomedical Research Centre in Ageing, Newcastle, UK.
J
J
Frith
P
P
Zalewski
J J
JJ
Klawe
J
J
Pairman
A
A
Bitner
M
M
Tafil-Klawe
J L
JL
Newton
D001341:Autonomic Nervous System / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D016022:Case-Control Studies; D003935:Diagnostic Techniques, Cardiovascular; D015673:Fatigue Syndrome, Chronic / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019095:Point-of-Care Systems; D012372:ROC Curve; D013564:Sympathetic Nervous System / Q000502:physiology