De groep van Hurwitz en Klimas hebben de hartfunktie en het bloedvolume

van ME/CVS-patiënten en "inaktieve mensen" onderzocht en vergeleken.

Daarbij werden ME/CVS-patiënten op basis de ernst van hun klachten

in twee groepen ingedeeld: "zware"en "lichte gevallen" (zie tabel hieronder).

Opvallend is dat de "zware gevallen" vrijwel allemaal te maken karakteristieke ME-

klachten (post-exertional malaise, zwakte, spierpijn en neurokognitieve problemen).

Table 2 Characteristics and symptoms are presented for Chronic Fatigue Syndrome/CFS groups, subdivided by reported illness severity

Iemand werd ingedeeld als zwaar geval als hij/zij minstens 7 CVS-klachten had.

Het totale bloedvolume, het plasmavolume en het rode bloedcellen-volume

van "zware gevallen" zijn kleiner dan die van lichte gevallen",

die op zijn beurt weer kleiner zijn dan die van "inaktieve mensen" (tabel 4).

Table 4 Mean/±SE values of blood volume measures, adjusted for age and education

* p < .10, ** p < .05, *** p < .01, **** p < .001;

De lagere slagindex, het lagere hart-minuut-volume en het lagere slagvolume (tabel 3) wordt volgens de auteurs vrijwel volledig verklaard door het lagere bloedvolume.

en niet door de lagere kontraktiliteit (samenstrekkingskracht van de hartspier)

Volgens de onderzoekers wijkt de zuurstofopname niet af van "inaktieve mensen"

[hetgeen betekent dat één fietstest niet volstaat om de ME/CVS te objektiveren, FT].

Dit duidt er volgens de onderzoekers op dat het lage bloedvolume etc.

géén gevolg zijn van "dekonditionering" (inaktiviteit, "luiheid").

Voorts is het opmerkelijk dat de auteurs opmerken dat Miwa en kollega's in 2008

(klik hier) bij 61% van de ME/CVS-patiënten een "klein hart-syndroom" konstateerden.

En ik altijd maar denken dat ik een groot hart had...

Table 3 Mean/±SE values for measures of cardiac function and structure, adjusted for age and education

ME/CVS een medisch onverklaarbaar symdroom?

Het enige wat ik onverklaarbaar is,

is het feit dat "vermoeidheidsexperts" ME/CVS de feiten blijven negeren.

Begrippen

Kontraktiliteit (Contractility):

Vermogen van het hart zich te kunnen samentrekken, klik hier.

Slagvolume (Stroke Volume, SV):

De hoeveelheid bloed per samentrekking (hartslag);

bedraagt 50 tot 100mL en is afhankelijk van de preload of voorbelasting,

de afterload of nabelasting en de kontractiliteit van de ventrikels, klik hier of hier.

Slagindex (Stroke Index, SI):

Slagvolume gekorrigeerd naar grootte van een persoon (grootte in cm2).

Hart-minuut-volume (Cardiac Output, CO):

hartslagen per minuut * slagvolume, klik hier.

Hartslagindex (cardiac index, CI):

Cardiac Output gekorrigeerd naar grootte van een persoon (grootte in cm2).

Lichaamsvaatweerstand (Systemic Vascular Resistance/SVR):

Weerstand die het bloed ondervindt bij de circulatie door de bloedvaten, vasokon- striktie/vaatvernauwing doet SVR stijgen, vasodilatatie doet SVR dalen, klik hier.

Totaal bloedvolume (TBV),

Plasmavolume (PV) en

Rode bloedcellen-volume (RBCV: bloed - plasma).

Citaten

More recently, others reported that CFS patients had greater prevalence of small heart syndrome, defined via chest roentgenogram as a cardiothoracic ratio ≤42%; 61% of CFS compared with 24% of control subjects had small heart syndrome [Miwa, 2008].

...

Indeed, when direct blood volume measurements were performed, subnormal plasma blood volume/PV and red blood cell volume/RBCV has been observed respectively in 53% and 84% of the severely affected CFS patients, and 63% of these persons displayed low total blood volume/TBV [Streeten en Bell, 1998].

...

Study-eligible ... subjects:

8   were not being treated in the 3 months preceding study entry with medications

     having a cardiovascular, metabolic, autonomic, immune, or endocrine effect;

10 presented no electrocardiogram/ECG arrhythmias associated with tachycardia,

     bradycardia/<50 bpm, heart block or myocardial infarction;

11 were not pregnant and had no intention to become pregnant;

...

When cardiac contractility was controlled, the lack of significant correction in cardiac volume measures (CI, SI, EDV) indicated that these CFS functional differences were unlikely related to contractility. Similarly, the finding that the sedentary-control subjects, did not display a decrement in cardiac volume level, suggests that the lower cardiac volume level in the CFS subjects was not likely due to deconditioning. This conclusion is supported by the observation that the CFS groups displayed a similar aerobic capacity deficit as the sedentary-control group. Moreover, the aerobic capacity deficit did not correlate significantly with the decrement in cardiac volume in these subjects.

...

... the TBV deficit accounted for 91-94% of the group differences in cardiac volume. Therefore, it is probable that the decrement in CFS cardiac volume is secondary to a hypovolemic condition, rather than due to a primary cardiac functional abnormality. However, without a demonstration that blood volume treatment provides a resolution of the cardiac abnormalities, such a conclusion cannot be made with certainty.

...

... there was a trend toward greater SVR in the severe-CFS subjects, which may have played a role in stimulating the observed cardiac wall thickening. Alternatively, given that CFS onset is often linked with recent infection and CFS patients tend to show an elevated prevalence of bacterial and/or viral infections, one possible source of the wall thickness differences may be infection. Human herpesvirus-6 (HHV-6), human parvovirus B19 (PVB19), and combined PVB19/HHV-6 are frequently found on cardiac biopsy in viral myocarditis patients. In addition, some evidence suggests that these viruses may trigger and perpetuate fatigue syndromes in non-CFS and CFS patients. However, we are not aware of any reported cases of viral myocarditis in CFS patients.

Chronic fatigue syndrome: illness severity, sedentary lifestyle, blood volume and evidence of diminished cardiac function.

Clin Sci/Lond. 2009 May 26. [Epub ahead of print]

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 contractility.

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 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]

doi:10.1042/CS20090055