Non-invasive estimation of pulmonary capillary wedge (PCW) pressure by an echophonocardiographic technique is reported. The ratio of time interval from the Q-wave to the C-point (echocardiogram) (Q-C) and from aortic closing (A2) to the E-point (A2-E) correlated well with the measured PCW pressure (r = 0.89; P = 0.001). When these two intervals were subtracted (A2-E)-(Q-C) the correlation was r = -0.90 (P = 0.001).