Reproducibility of Cardiopulmonary Exercise Parameters in Patients With Valvular Heart Disease

¹ From the German Heart Centre, Department of Cardiology, Munich, Federal Republic of Germany

Study objectives: To determine the degree of reproducibility of exercise parameters in patients with chronic heart failure. Parameters such as treadmill walking time (TWT), oxygen uptake (VO₂), heart rate, oxygen pulse, minute ventilation (VE) ventilatory equivalents for oxygen uptake (VE/VO₂) and carbon dioxide output (VCO₂), and respiratory quotient at both anaerobic threshold (AT) and peak exercise (PE) each were assessed.

Design: Using the Naughton-Weber protocol, two repeated cardiopulmonary treadmill exercise tests were performed after detailed instructions prior to the first test and on strict adherence to standardized investigational conditions, viz, at the same time of day and at the same ambient temperature, receiving constant medication, and while in a 12-h fasting state.

Patients: The studies were carried out in 17 patients with chronic heart failure due to valvular heart disease considered candidates for intervention because of symptoms. According to Weber's classification of functional capacity, 10 patients were in class A (VO₂ max >20 mL O₂/min/kg), 5 patients were in class B (16 to 20 mL O₂/min/kg), and the remaining 2 were in class C (10 to 16 mL O₂/min/kg).

Measurements: Parameters assessed were TWT, VO₂, heart rate, oxygen pulse, VE and ventilatory equivalents for oxygen (VE/VO₂) and carbon dioxide (VE/VCO₂) both at AT and at PE. To reflect reproducibility, correlation coefficients (r) were calculated.

Results: An excellent reproducibility was found for TWT (r=0.963, p<0.0001), VO₂ at AT in percent of predicted VO₂max (r=0.984, p<0.0001), VO₂ at PE (r=0.996, p<0.0001), heart rate at AT (r=0.943, p<0.0001) and at PE (r=0.928, p<0.0001), oxygen pulse at AT (r=0.980, p<0.001) and at PE (r=0.991, p<0.0001), VE at AT (r=0.949, p<0.0001) and at PE (r=0.912, p<0.0001) as well as VE/VO₂ at AT (r=0.942, p<0.0001) and at PE (r=0.781, p<0.0002) and VE/VCO₂ at AT (r=0.995, p<0.0001) and at PE (r=0.943, p<0.0001), respectively.

Conclusions: On adherence to standardized conditions, an excellent reproducibility existed for TWT, VO₂ (reflecting cardiac output), ventilation, and heart rate as well as derived parameters, rendering cardiopulmonary exercise testing a reliable means of quantification of heart failure as a prerequisite for enabling diagnostic or therapeutic decisions.

Key Words: cardiopulmonary exercise testing • reproducibility • valvular heart disease

Submitted on January 17, 1996
Accepted on April 4, 2007

This article has been cited by other articles:

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