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(minstens) vier subgroepen

op basis van de

dubbele inspanningstest








Volgens een presentatie van Betsy Keller op de recente IACFS-ME conferentie

kunnen we CVS-patiŽnten op basis van de dubbele fietstest in vier groepen indelen:

  1. patiŽnten waarvan de maximale zuurstofopname de tweede dag beduidend lager is (34%) en/of
  2. patiŽnten waarvan de zuurstofopname bij de verzuringsdrempel sterk afneemt (39%) en/of,
  3. patiŽnten die op een andere wijze abnormaal reageren op de dubbele fietstest, en
  4. patiŽnten die bij de tweede inspaningstest vergelijkbaar presteren/niet achteruit gaan (29%)

De vierde groep zou nader onderzocht moeten worden,

wellicht omdat deze CVS-patiŽnten wel normaal reageren op 'revalidatieprogramma's'.




Subsets of ME/CFS patient responses to a 2-day CPET

IACFS/ME Conference, 2016 October 27-30. Fort Lauderdale, Florida.

Betsy Keller.


Betsy Keller,


Department of Exercise and Sport Sciences,

Ithaca College,

318 Center for Health Sciences,


NY 14850





Studies to assess the efficacy of a two-day cardiopulmonary exercise test (2-d CPET) protocol

to identify post-exertion malaise (PEM) in ME/CFS

first revealed that ME/CFS patients often fail to reproduce peak VO2 (VO2peak) during test 2

due to PEM provoked with test 1.


Subsequent research indicated that a subset of patients

failed to reproduce VO2 at ventilatory/anaerobic threshold (VAT),

but did reproduce VO2peak,

suggesting that responses to exertion may distinguish subsets of patients.


Identifying subsets of ME/CFS patient responses to exertion

would enable us to further explore other potential correlates,

such as metabolic markers or bacterial microbiome of the gut.





To classify the responses of ME/CFS patients to a 2-d CPET protocol

to determine if ME/CFS patients demonstrate subsets of responses

in addition to failure to reproduce VO2peak or VO2@VAT.





Responses to a 2-d CPET protocol were evaluated for 94 ME/CFS patients.


Patient responses were evaluated based on failure to reproduce VO2peak or VO2@VAT,

as well as failure to respond normally with regard to

autonomic parameters (heart rate, blood pressure), ventilatory parameters,

as well as cases that reproduced CPETs within normal variation.





Of 97 cases,

34% comprised a subset of responders that failed to reproduce VO2peak, and

39% failed to reproduce VO2@VAT within normal variation.


Additionally, subsets were also described by

autonomic anomalies (43%), ventilatory anomalies (47%), and

normal reproduction of CPETs (29%).


Membership in more than one subset by several cases explained

the sum total of all subsets greater than 100%.





Assessment of PEM using the 2-d CPET protocol

should consider abnormal responses to exertion that extend

beyond VO2peak or VO2@VAT and

consider disruption of autonomic and ventilatory responses

as indicators of inappropriate recovery, or PEM, following exertion.


Additionally, patients diagnosed with ME/CFS

who reproduce the 2-day CPET within normal parameters

may describe a unique subset that requires further study.


Preliminary data will be discussed

which indicates that this subset may correspond with other prognostic indicators.