title: Abnormal impedance cardiography predicts symptom severity in chronic fatigue syndrome.
abstract: BACKGROUND
  Findings indicative of a problem with circulation have been reported in patients with chronic fatigue syndrome (CFS). We examined this possibility by measuring the patient's cardiac output and assessing its relation to presenting symptoms.
  
  
  METHODS
  Impedance cardiography and symptom data were collected from 38 patients with CFS grouped into cases with severe (n = 18) and less severe (n = 20) illness and compared with those from 27 matched, sedentary control subjects.
  
  
  RESULTS
  The patients with severe CFS had significantly lower stroke volume and cardiac output than the controls and less ill patients. Postexertional fatigue and flu-like symptoms of infection differentiated the patients with severe CFS from those with less severe CFS (88.5% concordance) and were predictive (R2 = 0.46, P < 0.0002) of lower cardiac output. In contrast, neuropsychiatric symptoms showed no specific association with cardiac output.
  
  
  CONCLUSIONS
  These results provide a preliminary indication of reduced circulation in patients with severe CFS. Further research is needed to confirm this finding and to define its clinical implications and pathogenetic mechanisms.
authors.affiliation: Department of Neurosciences, CFS Cooperative Research Center, University of Medicine and Dentistry of New Jersey, Newark, NJ, USA. apeckerm@njneuromed.org
authors.forename: Arnold
authors.initials: A
authors.lastname: Peckerman
authors.forename: John J
authors.initials: JJ
authors.lastname: LaManca
authors.forename: Kristina A
authors.initials: KA
authors.lastname: Dahl
authors.forename: Rahul
authors.initials: R
authors.lastname: Chemitiganti
authors.forename: Bushra
authors.initials: B
authors.lastname: Qureishi
authors.forename: Benjamin H
authors.initials: BH
authors.lastname: Natelson
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology*; D002307:Cardiography, Impedance / Q000379:methods / Q000706:statistics & numerical data; D015673:Fatigue Syndrome, Chronic / Q000175:diagnosis* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012044:Regression Analysis