[Reproducibility of spiro-ergometric exercise test parameters in patients with heart failure]

The aim of the study was to determine the degree of reproducibility of parameters of cardiopulmonary exercise (CPX) tests in patients with chronic heart failure (HF).

We investigated 30 patients (7 women, 23 men) with ages ranging from 44 to 68 and a mean age of 56 +/- 14.5 years with HF due to dilated cardiomyopathy (5 patients) and coronary artery diseases (25 patients). The mean ejection fraction was 24 +/- 6.2%. All the patients were symptomatically stable during the preceding 4 weeks. After a preliminary test, the patients underwent two treadmill CPX tests using modified Naughton protocol with a 1-week interval between tests. CPX tests were performed at the same time of the day, using the same equipment and the patients were receiving constant medication. The reproducibility was assessed for: Rest heart rate (HRrest), oxygen uptake at the anaerobic threshold (VO2AT) and peak exercise (VO2peak), carbon dioxide production (VCO2peak), ventilatory equivalent of carbon dioxide (VE/VCO2peak) and oxygen (VE/VO2peak), end-tidal partial pressure for carbon dioxide (PETCO2peak), exercise time (T) and respiratory exchange ratio (RER).

The reproducibility was found for all analyzed parameters of CPX tests: HRpeak (p < 0.0001), VO2AT (p < 0.0001), T (p < 0.001), HRpeak (p < 0.0001), VO2peak (p < 0.0001), VO2peak%N (p < 0.0001), VE/VCO2peak (p < 0.0001), VE/VO2peak (p < 0.0001), PETCO2peak (p < 0.0001), RER (p < 0.004).

On adherence to standardized conditions, an excellent reproducibility exists for the most important parameters of cardiopulmonary exercise tests. CPX tests provide a useful and objective method of assessing functional capacity and diseases progression in patients with heart failure.