The aim of the present study was to examine the nailfold capillary morphology and dynamics in treated chronic heart failure (CHF) in relation to parameters of left ventricular structure and function. Twenty patients with CHF class II according to the New York Heart Association underwent a capillaroscopic examination at the finger nailfold using a computerized videophotometric system (Capiflow®) at rest and after 1 min arterial occlusion. Study parameters ere number, length and diameter of the capillaries as well as capillary blood velocity (CBV). Further experiments included echocardiography and determination of left ventricular ejection fraction by Tc scintigraphy. Nailfold capillaries in established CHF are enlarged and the CBV is dramatically decreased. The reactive hyperemic response to 1 min arterial occlusion is attenuated. CBV correlates positively with left ventricular ejection fraction (r = 0.61, p = 0.01) and inversely with left ventricular end-diastolic (r = -0.56, p = 0.04) and end-systolic (r = -0.69, p = 0.01) diameters. The time-to-peak flow after 1 min arterial occlusion is positively related (r = 0.68, p < 0.05) to the duration of CHF. Our data indicate that finger microcirculation in CHF deteriorates as a function of the severity and duration of heart failure