title: Postural orthostatic tachycardia syndrome is an under-recognized condition in chronic fatigue syndrome.
abstract: BACKGROUND
  It has been suggested that postural orthostatic tachycardia syndrome (POTS) be considered in the differential diagnosis of those with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). Currently, measurement of haemodynamic response to standing is not recommended in the UK NICE CFS/ME guidelines.
  
  
  OBJECTIVE
  To determine prevalence of POTS in patients with CFS/ME.
  
  
  METHODS
  Observational cohort study.
  
  
  METHODS
  Fifty-nine patients with CFS/ME (Fukuda criteria) and 52 age- and sex-matched controls underwent formal autonomic assessment in the cardiovascular laboratory with continuous heart rate and beat-to-beat blood pressure measurement (Task Force, CNSystems, Graz Austria). Haemodynamic responses to standing over 2 min were measured. POTS was defined as symptoms of orthostatic intolerance associated with an increase in heart rate from the supine to upright position of >30 beats per minute or to a heart rate of >120 beats per minute on standing.
  
  
  RESULTS
  Maximum heart rate on standing was significantly higher in the CFS/ME group compared with controls (106 +/- 20 vs. 98 +/- 13; P = 0.02). Of the CFS/ME group, 27% (16/59) had POTS compared with 9% (5) in the control population (P = 0.006). This difference was predominantly related to the increased proportion of those in the CFS/ME group whose heart rate increased to >120 beats per minute on standing (P = 0.0002). Increasing fatigue was associated with increase in heart rate (P = 0.04; r(2) = 0.1).
  
  
  CONCLUSIONS
  POTS is a frequent finding in patients with CFS/ME. We suggest that clinical evaluation of patients with CFS/ME should include response to standing. Studies are needed to determine the optimum intervention strategy to manage POTS in those with CFS/ME.
authors.affiliation: Northern CFS/ME Clinical Network, Equinox House, Silver Fox Way, Cobalt Business Park, Newcastle upon Tyne.
authors.forename: A
authors.initials: A
authors.lastname: Hoad
authors.forename: G
authors.initials: G
authors.lastname: Spickett
authors.forename: J
authors.initials: J
authors.lastname: Elliott
authors.forename: J
authors.initials: J
authors.lastname: Newton
mesh_terms: D000328:Adult; D001794:Blood Pressure; D016022:Case-Control Studies; D015331:Cohort Studies; D015673:Fatigue Syndrome, Chronic / Q000150:complications / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D054972:Postural Orthostatic Tachycardia Syndrome / Q000175:diagnosis* / Q000453:epidemiology; D015995:Prevalence