[Cardiopulmonary exercise test and heart rate variability in patients with congestive heart failure who underwent physical rehabilitation].

Physical rehabilitation of patients with heart diseases is a well-known therapeutical method used in patients with heart failure. However there is no consensus regarding rehabilitation program for these patients. The aim of this study was to assess tolerance of physical exercise and parameters of heart rate variability in patients with chronic heart failure who were exercised using different models of training. 42 patients (mean age 55.9 +/- 8.2) with chronic heart failure (NYHA class II and III) were included into this study. They were divided randomly into three groups, each number 14 patients: group A--patients who were trained according to model with progressive increase of workload, group B--patients with interval training, and group C--patients who were not trained at all. The study groups did not differ in average age, BMI, NYHA class, or pharmacological treatment. All patients from groups A and B were rehabilitated during six months, 3 times per week for 1.0 hour each time. All patients were submitted to the following examinations before and after six months of training: echocardiography, cardiopulmonary exercise test and 24-hour ECG recording with evaluation of time-domain HRV parameters. In groups A and B we observed an improvement in exercise capacity, which was more pronounced in group A. This improvement was observed as increase in total exercise time when compared with group B and C (839.1 +/- 98.3 sec vs 472.4 +/- 39.7 sec vs 347.92 +/- 61.0 sec respectively at p < 0.0001), and increase in workload (6.28 +/- 0.8 MET vs 3.9 +/- 0.2 MET vs 2.6 +/- 0.63 MET respectively in the study groups). We also found improved cardiopulmonary exercise test. After six months we observed significant differences in all parameters between group A and C, and in VO2max between group B and C (16.5 +/- 1.9 vs 14.1 +/- 1.9 ml/kg/min, p < 0.01) and in VE/VCO2 (37.8 +/- 4.2 vs 40.4 +/- 6.7 l/min, p < 0.01). After 6 months we also found significant differences between group A and B in HRV parameters which reflect total activity of the autonomous system (SDNN--174.0 vs 96.0 at p < 0.0001; SDANNI--138.1 vs 83.2 at p < 0.0001) and between group A and group C (174.0 vs 78.4, p < 0.0001). In parameters that reflect parasympathetical activity of the autonomous system there were significant changes between group A and group B (rMSSD--42.5 vs 24.7 at p < 0.001, pNN50 18.5 vs 4.2, p < 0.001) and between group A and group C (rMSSD--42.5 vs 16.7 at p < 0.001, pNN50 18.5 vs 4.2 at p < 0.001). Regular exercise training in patients with chronic heart failure, using especially the progressive increase of workload, improves exercise capacity without any negative influence on systolic and diastolic function parameters of the left ventricle. In these patients we may also observe beneficial changes in HRV parameters.