Abnormal impedance cardiography predicts symptom severity in chronic fatigue syndrome

Abstract

ABSTRACT: Background: Findings indicative of a prob-lem with circulation have been reported in patients with chronic fatigue syndrome (CFS). We examined this pos-sibility by measuring the patient’s cardiac output and assessing its relation to presenting symptoms. Methods: Impedance cardiography and symptom data were col-lected 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 con-trol 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 associ-ation 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 implica-tions and pathogenetic mechanisms. KEY INDEXIN