['The relationship between isovolumic left ventricular (LV) relaxation and LV filling pressures remains incompletely explored. If there is a relationship between the rate of early diastolic LV relaxation and LV end-diastolic pressure, this would have important implications concerning both our understanding and, potentially, our treatment of LV diastolic dysfunction.', 'To examine the baseline hemodynamic correlates of LV end-diastolic pressure in patients with both normal and abnormal LV function.', 'The relationships between LV end-diastolic pressure, a variety of hemodynamic parameters (tau, the rate of LV isovolumic relaxation, LV peak positive+dP/dt, LV peak systolic pressure and heart rate), measures of LV end-systolic and end-diastolic volume, and age were determined using regression analysis techniques in 104 patients with normal LV systolic function and 90 patients with an LV ejection fraction of less than 40%.', 'Univariate analysis demonstrated a correlation between tau and LV end-diastolic pressure (r=0.743, P<0.001). There were significant univariate relationships between a number of other hemodynamic variables and LV end-diastolic pressure. A multiple regression model demonstrated that tau made the most important contribution to a model where LV end-diastolic pressure is the dependent variable. LV peak systolic pressure and heart rate also made significant contributions to the model. In 33 of these patients, when LV end-diastolic pressure was reduced using an inferior vena cava occlusion balloon, tau did not change. The acute administration of clonidine (n=11) caused an increase in LV end-diastolic pressure that was closely correlated with an observed increase in tau (r=0.843, P<0.001).'] Is left ventricular isovolumic relaxation a predictor of left ventricular end-diastolic pressure?