A decrease in left ventricular (LV) systolic function is accompanied by a decrease in maximal relaxation velocity in LV long-axis direction, but is it also accompanied by a decrease in right ventricular (RV) long-axis function? To study this 35 consecutive patients were examined by echocardiography. Ejection fraction (LVEF) and mitral annulus motion (MAM) were used as indices of LV systolic function and tricuspid annulus motion (TAM), that is the systolic shortening in RV long-axis direction, was used as an index of RV systolic long-axis function. In the same way the maximal relaxation velocity in LV long-axis direction, that is the maximal diastolic velocity of MAM (MDV MAM), has been suggested as an index of LV diastolic function the maximal diastolic velocity of TAM (MDV TAM) can be supposed to be an index of RV diastolic function measuring the maximal relaxation velocity in the RV long-axis direction. A significant positive correlation was found between MDV TAM and MAM (r = 0·64, P<0001) and LVEF (r = 0·54, P = 0·001) and between TAM and the two studied indices of LV systolic function, with the highest correlation to MAM (r = 0·68, P<0·001) and the lowest to LVEF (r = 0·57, P<0·001). Thus, a decrease in LV systolic function is accompanied by a decrease in both systolic and diastolic RV long-axis function, findings that probably are due to the close anatomical connection between the ventricles and to changes that occur in afterload of the RV secondary to LV systolic dysfunction.