I don't have the full text for this but happened to come across a second abstract which gives a little extra information:
Chronic fatigue syndrome: illness severity, sedentary lifestyle, blood volume and evidence of diminished cardiac function.
Hurwitz BE, Coryell VT, Parker M, Martin P, Laperriere A, Klimas NG, Sfakianakis GN, Bilsker MS.
Clin Sci (Lond). 2009 Oct 19;118(2):125-35.
Behavioral Medicine Research Center, University of Miami, Miami, FL 33136, USA. firstname.lastname@example.org
The study examined whether deficits in cardiac output and blood volume in a CFS (chronic fatigue syndrome) cohort were present and linked to illness severity and sedentary lifestyle.
Follow-up analyses assessed whether differences in cardiac output levels between CFS and control groups were corrected by controlling for cardiac contractility and TBV (total blood volume).
The 146 participants were subdivided into two CFS groups based on symptom severity data, severe (n=30) and non-severe (n=26), and two healthy non-CFS control groups based on physical activity, sedentary (n=58) and non-sedentary (n=32).
Controls were matched to CFS participants using age, gender, ethnicity and body mass.
Echocardiographic measures indicated that the severe CFS participants had 10.2% lower cardiac volume (i.e. stroke index and end-diastolic volume) and 25.1% lower contractility (velocity of circumferential shortening corrected by heart rate) than the control groups.
Dual tag blood volume assessments indicated that the CFS groups had lower TBV, PV (plasma volume) and RBCV (red blood cell volume) than control groups.
Of the CFS subjects with a TBV deficit (i.e. > or = 8% below ideal levels), the mean+/-S.D. percentage deficit in TBV, PV and RBCV were -15.4+/-4.0, -13.2+/-5.0 and -19.1+/-6.3% respectively.
Lower cardiac volume levels in CFS were substantially corrected by controlling for prevailing TBV deficits, but were not affected by controlling for cardiac contractility levels.
Analyses indicated that the TBV deficit explained 91-94% of the group differences in cardiac volume indices.
Group differences in cardiac structure were offsetting and, hence, no differences emerged for left ventricular mass index.
Therefore the findings indicate that lower cardiac volume levels, displayed primarily by subjects with severe CFS, were not linked to diminished cardiac contractility levels, but were probably a consequence of a co-morbid hypovolaemic condition.
Further study is needed to address the extent to which the cardiac and blood volume alterations in CFS have physiological and clinical significance.
PMID: 19469714 [PubMed - indexed for MEDLINE]
CHRONIC FATIGUE SYNDROME: ILLNESS SEVERITY,
SEDENTARY LIFESTYLE, BLOOD VOLUME AND CARDIAC
STRUCTURE AND FUNCTION
Virginia T. Coryell, M.S., Barry E. Hurwitz, Ph.D., Meela Parker,
CCT, RDCS, Pedro Martin, M.D., Psychology, Arthur LaPerriere,
Ph.D., Psychiatry & Behavioral Sciences, University of Miami, Coral
Gables, FL, Nancy G. Klimas, M.D., George N. Sfakianakis, M.D.,
Martin S. Bilsker, M.D., Medicine, University of Miami, Miami, FL
This study evaluated cardiac structure and function in Chronic Fatigue
Syndrome (CFS) and non-CFS subjects, while controlling for CFS
illness severity and sedentary lifestyle.
In addition, we examined
whether differences in total blood volume (TBV) could account for
differences in cardiac outcomes. Study groups were: severe CFS
(n=30), non-severe CFS (n=26), sedentary control (n=30) and nonsedentary
Severe illness in CFS subjects was defined as
>=7 of 10 CFS symptoms, self-rated as moderate or severe, that
persisted for >=6 mos.
Sedentary and non-sedentary physical activity
status were defined, respectively, as a reported energy expenditure of
<=1500 and >=2200 kcals/wk.
Measures were obtained from selfreport
of medical history, fatigue and physical activity, as well as
echocardiography and dual tag blood volume testing.
Among potential covariates, group differences emerged for age and education, and hence
were controlled in analyses.
The analyses showed that the severe CFS
group relative to the non-CFS groups evidenced diminished cardiac
index (CI) due to diminished stroke index (SI; ps<.05) and not to heart
The diminished SI in the severe CFS group was due to
lower end diastolic volume (EDV) and contractility (VCFc; ps<.05),
with no group differences in end systolic volume.
Follow-up analyses showed that the percent difference from ideal TBV was lower in the
severe CFS group than the non-severe and sedentary-control groups
(adjusted meanSE: -6.0%1.3 vs. -1.6%1.3 vs. 6.4%1.8; p<.001).
When these TBV differences were controlled, the group differences in
CI, SI, EDV and VCFc were no longer significant.
Notably, the cardiac measures in CFS subjects did not correlate significantly with reported
Therefore, the findings suggest that although a cardiac function
deficit is more probable in severely-affected CFS persons, it is not
linked to sedentary lifestyle or perceived fatigue, but is largely
accounted for by a deficit in blood volume.