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JOURNAL
OF
SPORTS SCIENCE &
MEDICINE
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Research
article
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QUANTIFICATION OF THE IMPAIRED CARDIAC OUTPUT RESPONSE TO EXERCISE IN HEART FAILURE: APPLICATION OF A NON-INVASIVE DEVICE |
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Jonathan Myers1  ,
Pradeep Gujja2, Suresh Neelagaru3, Leon Hsu1
and Daniel Burkhoff4 |
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1Cardiology Division, Veterans Affairs Palo Alto Health Care System and Stanford University, Palo Alto, CA, 2Texas Tech University of Health Sciences, Amarillo, Texas, 3Lonestar Arrythmia and Heart Failure Center, Amarillo, Texas, 4Columbia University, New York, USA |
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© Journal of Sports Science and Medicine (2009) 8, 344 - 351 |
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| ABSTRACT | |||
| An impaired cardiac output (CO) response to exercise is a hallmark
of chronic heart failure (CHF), and the degree to which CO is impaired is
related to the severity of CHF and prognosis. However, practical methods
for obtaining cardiac output during exercise are lacking, and what constitutes
and impaired response is unclear. Forty six CHF patients and 13 normal subjects
underwent cardiopulmonary exercise testing (CPX) while CO and other hemodynamic
measurements at rest and during exercise were obtained using a novel, non-invasive,
bioreactance device based on assessment of relative phase shifts of electric
currents injected across the thorax, heart rate and ventricular ejection
time. An abnormal cardiac output response to exercise was defined as achieving
< 95% of the confidence limits of the slope of the relationship
between CO and oxygen uptake (VO2). An impaired CO slope identified
patients with more severe CHF as evidenced by a lower peak VO2,
lower peak CO, heightened VE/VCO2 slope, and lower oxygen uptake
efficiency slope. CO can be estimated during exercise using a novel bioreactance
technique; patients with an impaired response to exercise exhibit reduced
exercise capacity and inefficient ventilation typical of more severe CHF.
Non- invasive measurement of cardiac performance in response to exercise
provides a simple method of identifying patients with more severe CHF and
may complement the CPX in identifying CHF patients at high risk. Key words: Heart failure, cardiac output, oxygen uptake, exercise testing. |
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