In our study we tried to evaluate systolic and diastolic function in patients with chronic heart failure (CHF) by using some echocardiographic parameters and invasively measured pulmonary capillary wedge pressure (PCWP). We studied 19 patients with CHF NYHA II-III at rest, at the end of isometric exercise (handgrip) and during a bicycle stress test. Right heart catheterization and echocardiography were simultaneously performed. We measured exchange of blood gases, end diastolic volume (EDV), end systolic volume (ESV), ejection fraction (EF), peak E velocity, peak A velocity, E/A ratio, deceleration time of E wave (DT), time of mitral regurgitation (MR) and effective filling period of left ventricle (FP). We divided patients according to the median of PCWP at rest into two groups: group A with PCWP< or =11 mmHg (10 pts), group B with PCWP>11 mmHg (9 pts). In group A mean PCWP at rest was 6+/-2 mmHg, during handgrip 12+/-4 mmHg and during bicycle exercise 18+/-6 mmHg. In group B mean values of PCWP were 19+/-6 mmHg, 26+/-11 mmHg and 33+/-5 mmHg, respectively. All values were significantly higher in group B (P<0.01). There was a significant difference in pVO2: in group A 18.8+/-3.5 vs. 14.7+/-3.3 ml/kg per min in group B (P<0.03). No differences between the groups were noticed in EDV, ESV and EF. The E/A ratio in group A was less than 1, in group B greater than 1 with the restrictive pattern. No differences between the groups were observed in MR and FP at rest. During bicycle exercise, MR was significantly longer (284+/-98 vs. 164+/-79 ms; P<0.05) and FP shorter (322+/-99 vs. 421+/-74 ms; P<0.05) in group B than in group A. The functional capacity of patients with CHF is influenced not only by EF and other systolic variables, but also by filling conditions. The duration of effective diastole may be one of the most important of them.