Determination of mean pulmonary capillary pressure by a noninvasive technique.

The feasibility of estimating the mean pulmonary capillary pressure (PCP) by simultaneous noninvasive recording of the ECG, phonocardiogram, and mitral valve echocardiogram was tested in 36 patients with miscellaneous heart lesions. The recordings were made in close sequence with direct measurement of PCP by a catheter. The interval from the onset of the QRS complex to the echocardiographic point C of mitral valve closure (Q-C) and the time from the aortic valve closure sound to the E point of the mitral echocardiogram (A2-E) were measured. The difference between these two intervals exhibited a good linear correlation with the PCP. A better correlation was found between the ratio (Q-C)/(A2-E) and the PCP, which is potentially useful in the noninvasive determination of PCP in several forms of heart disease.