Clinical science (Lond). 2009 May 26.
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.
This study examined whether deficits in cardiac
output and blood volume in a Chronic Fatigue
Syndrome (CFS) cohort were present and linked to
illness severity and sedentary lifestyle.
Follow-up analyses assessed whether differences
between CFS and control groups in cardiac output
levels were corrected by controlling for cardiac
contractility and total blood volume (TBV).
The 146 participants were subdivided into two CFS
groups based on symptom severity data, severe
(n=30) vs. non-severe (n=26), and two healthy
non-CFS control groups based on physical activity,
sedentary (n=58) vs. non-sedentary (n=32).
Controls were matched to CFS participants using age,
sex, ethnicity and body mass.
Echocardiographic measures indicated that the
severe CFS participants displayed 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
CFS groups had lower TBV, plasma volume (PV) and
red blood cell volume (RBCV) than control groups.
Of the CFS subjects with a TBV deficit (i.e., >/=8%
below ideal levels), the mean +/-SD percent deficit
in TBV, PV and RBCV were 15.4+/-4.0, 13.2+/-5.0,
and 19.1+/-6.3, respectively.
Lower CFS cardiac volume levels were substantially
corrected by controlling for prevailing TBV deficits,
but were not affected by controlling for cardiac
Analyses indicated that the TBV deficit explained
91-94% of the group differences in cardiac volume
Group differences in cardiac structure were offsetting
and hence no differences emerged for LV mass index.
Therefore, the findings indicate that lower cardiac
volume levels, displayed primarily by persons with
severe-CFS, were not linked to diminished cardiac
contractility levels, but were likely a consequence of
a comorbid hypovolemic condition.
Further study is needed to address the extent to
which the CFS cardiac and blood volume alterations
have physiological and clinical significance.
PMID: 19469714 [PubMed - as supplied by publisher]