Can anaerobic threshold be used as an end-point for therapeutic trials in heart failure?

Cohen-Solal, A; Jf, Aupetit; Guéret, Pascal; Kolsky, H; Zannad, F.

doi:10.1093/oxfordjournals.eurheartj.a060482

Cited by 25 publications

(11 citation statements)

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“…This is thought to be due to erratic respiration25 and delayed peripheral metabolic changes23 in patients with CHF. Poor inter-observer reproducibility and bias arise because of the multiple methods used to calculate the anaerobic threshold 22. Attempts to eradicate this problem using computerised techniques have proved unsuccessful.…”

Section: Discussionmentioning

confidence: 99%

The role of exercise testing in the evaluation and management of heart failure

Wright

Tan

1999

Postgraduate Medical Journal

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SummaryThe clinical syndrome of heart failure has been investigated so extensively that it may now almost be regarded as a metabolic disorder. Although an initial insult reduces cardiac pump eYcacy, the resultant physiological response culminates in complex neurohormonal dysfunction. This has created confusion and prevented the acceptance of a universal definition of cardiac failure. With much current research concentrating on the pharmacological modification of neuroendocrine imbalance, it is easy to lose sight of the fundamental principles behind heart failure management, namely, to improve cardiac function. In attempting to achieve this, the issues of morbidity and mortality must be addressed jointly; they are not mutually exclusive entities. Discrepant results between mortality studies and changes in exercise capacity have undermined the value of exercise testing. Because a treatment enhances longevity we should not ignore its eVect on symptomatic status, and likewise we should not discard a therapy, which improves function because adverse events result in occasional premature deaths. Informed patient choice must exist.Historically, exercise testing has been quintessential in our understanding and evaluation of heart failure. Peak oxygen consumption remains the best overall indicator of symptomatic status, exercise capacity, prognosis and hospitalisation.Unfortunately, muddling of surrogate and true end-points has confused many of these issues. Improved comprehension may be gained by applying the concept of cardiac reserve which has been described in a variety of heart conditions and used in cardiac failure patients to provide an indication of prognosis and functional capacity.

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Section: Discussionmentioning

confidence: 99%

The role of exercise testing in the evaluation and management of heart failure

Wright

Tan

1999

Postgraduate Medical Journal

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“…However, these techniques are not always successful [16] and show inter-observer variation. Confirming adequacy using a predetermined threshold for peak RER is therefore helpful in standardizing interpretation of therapeutic trials and whenever several centres (and therefore several observers) are involved.…”

Section: Clinical Significance Of Oscillations In Rermentioning

confidence: 99%

Impact of periodic breathing on measurement of oxygen uptake and respiratory exchange ratio during cardiopulmonary exercise testing

et al. 2002

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Metabolic exercise testing is valuable in patients with chronic heart failure (CHF), but periodic breathing may confound the measurements. We aimed to examine the effects of periodic breathing on the measurement of oxygen uptake ( V*O(2)) and respiratory exchange ratio (RER). First, we measured the effects of different averaging procedures on peak V*O(2) and RER values in 122 patients with CHF undergoing cardiopulmonary exercise testing. Secondly, we studied the effects of periodic breathing on V*O2) and RER in healthy volunteers performing computer-guided periodic breathing. Thirdly, we used a Fourier analysis to study the effects of periodic breathing on gas exchange measurements. The first part of the study showed that 1 min moving window gave a mean peak V*O(2) of 13.8 ml.min(-1).kg(-1) for the CHF patients. A 15 s window gave significantly higher values. The difference averaged 1.0 ml.min(-1).kg(-1) ( P <0.0001), but varied widely: 41% of subjects showed a difference greater than 1.0 ml.min(-1).kg(-1). RER values were also higher by an average of 0.09 ( P <0.0001); in 20% of subjects the difference was greater than 0.10. In the second part of the study, we found artefactual elevations of peak V*O(2) (without averaging) of 2.9 ml.min(-1).kg(-1) ( P <0.01) and of peak RER of 0.13 ( P <0.001), which were still significant when 30 s averaging was applied [delta(peak V*O(2))=1.8 ml.min(-1).kg(-1), P <0.01; deltaRER=0.08, P <0.001]. The third, theoretical, part of the study showed that values of carbon dioxide output and V*O(2) oscillate with different phases and amplitudes, resulting in oscillations in their ratio, RER. Averaging over 15 s or 30 s can be expected to give only 10% or 36% attenuation respectively. Thus periodic breathing causes variable artefactual elevations of measured peak V*O(2) and RER, which can be attenuated by using longer averaging periods. Clinical reports and research publications describing peak V*O(2) in CHF should be accompanied by details of the averaging technique used.

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“…The first is the increase in the socalled ventilatory equivalent for oxygen (VE/VO 2 ) with a constant ventilatory equivalent for CO 2 (VE/VCO 2 ) and second an increase in end-expiratory oxygen pressure with a constant end-expiratory pressure for CO 2 . However, VO 2 at anaerobic threshold is rarely utilized by itself to quantify exercise capacity but, more often, is used as an accessory tool to confirm the value of peak VO 2 [15]. As an alternative to anaerobic threshold the calculation of the VO 2 when the respiratory ratio (VCO 2 /VO 2 ) became = 1 has been proposed [15] but this is not the anaerobic threshold.…”

Section: Protocols and Measurementsmentioning

confidence: 99%

“…However, VO 2 at anaerobic threshold is rarely utilized by itself to quantify exercise capacity but, more often, is used as an accessory tool to confirm the value of peak VO 2 [15]. As an alternative to anaerobic threshold the calculation of the VO 2 when the respiratory ratio (VCO 2 /VO 2 ) became = 1 has been proposed [15] but this is not the anaerobic threshold.…”

Section: Protocols and Measurementsmentioning

confidence: 99%

Evolving Role of Cardiopulmonary Exercise Testing in Heart Failure and Cardiac Transplantation

Agostoni¹,

Guazzi²

2002

Clinical Exercise Testing

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Heart failure (HF) is a multiorgan syndrome and the cardiopulmonary exercise test (CPET) provides an overall assessment of functional capacity and prognosis. From a prognostic point of view, useful information is obtained from peak VO 2 and VE/VCO 2 slope. These are independent predictors of survival in patients with HF and can be combined with other prognostic elements. Furthermore, CPET allows to identify the organ which is most responsible for HF severity and to target therapy on. Indeed, the following are classical aspects of CPET in HF: (a) reduction in workload achieved, (b) reduction in peak exercise VO 2 , (c) reduction in VO 2 at anaerobic threshold, (d) reduction in VO 2 /work rate relationship, (e) reduction in oxygen pulse, (f) reduction in rest to peak heart rate differences, (g) reduction in tidal volume at peak exercise and anaerobic threshold, (h) increase in VE/VCO 2 slope, (i) reduction in expiratory flow reserve and (l) increase in peak exercise functional respiratory capacity.

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Can anaerobic threshold be used as an end-point for therapeutic trials in heart failure?

Cited by 25 publications

References 0 publications

The role of exercise testing in the evaluation and management of heart failure

The role of exercise testing in the evaluation and management of heart failure

Impact of periodic breathing on measurement of oxygen uptake and respiratory exchange ratio during cardiopulmonary exercise testing

Evolving Role of Cardiopulmonary Exercise Testing in Heart Failure and Cardiac Transplantation

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