Page 18 of the Overview for the Canadian Consensus Criteria (CCC), under the subheading: "Chronic orthostatic intolerance", says "Use tilt table test
or monitor the pulse and blood pressure while standing. Note: This monitoring must be done with caution and someone standing beside the patient." (my bolding)
https://www.mefmaction.com/images/stories/Overviews/ME-Overview.pdf
The CCC Overview also references this study re impedance cardiograph testing:
Am J Med Sci. 2003 Aug;326(2):55-60.
Abnormal impedance cardiography predicts symptom severity in chronic fatigue syndrome.
Peckerman A1,
LaManca JJ,
Dahl KA,
Chemitiganti R,
Qureishi B,
Natelson BH.
Author information
1
Department of Neurosciences, CFS Cooperative Research Center, University of Medicine and Dentistry of New Jersey, Newark, NJ, USA.
apeckerm@njneuromed.org
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.
https://www.ncbi.nlm.nih.gov/pubmed/12920435
Page one of the Overview, under "Natural Course" says: " Objective postural cardiac output abnormalities correlate with symptoms severity and reactive exhaustion."
I understand that the impedance cardiograph can indicate cardiac output. However, I believe the usual way to do this test is just supine.
Some researchers have done this test both supine, and then compare the patient's results to when they are standing while using the impedance cardiograph.
The comparison between supine results and standing may be quite revealing of cardiac function.