The pathogenesis of acute pulmonary edema in idiopathic dilated cardiomyopathy (IDC) is not completely understood. Because pulse-wave tissue Doppler imaging (TDI) allows a direct comparison between systolic as well as diastolic wall motion velocities, we tested the hypothesis that acute pulmonary edema is caused by both systolic and diastolic failure. We prospectively studied 65 patients. Forty patients had IDC (group 1), 15 of whom had recent-onset pulmonary congestion (group 1a, New York Heart Association [NYHA] functional classes III and IV) and 25 of whom were in clinically stable condition without signs of pulmonary congestion (group 1b, NYHA I and II). All of these patients were restudied after 3, 7, and 45 days. Groups 1a and 1b were compared with 25 subjects without evidence of heart disease (group 2). Peak systolic wall motion velocity (Vs), peak wall motion velocity of the early (Ve), and late (Va) filling waves were measured by TDI; mitral inflow pattern was determined by pulse-wave Doppler and left ventricular (LV) ejection fraction (EF) by 2-dimensional echocardiography. In those patients without pulmonary edema (controls and group 1b, n = 50), we found a positive correlation between LVEF and Vs (r = 0.72, p <0.001) and between LVEF and Ve (r = 0.79, p <0.001). Early diastolic wall motion velocity always exceeded peak systolic wall motion velocity (Ve/Vs ratio >1). In patients with IDC with recent-onset pulmonary congestion (group 1a), Ve was significantly lower compared with group 1b (3.5 +/- 0.2 vs 4.9 +/- 0.4 cm/s, p <0.01, Ve/Vs ratio <1). Clinical improvement was paralled by a gradual increase in Ve (3.5 +/- 0.2 to 6.8 +/- 0.3 cm/s, p <0.01) but not in Vs or LVEF. Thus, in patients with IDC acute pulmonary edema is exclusively caused by diastolic rather than systolic failure.