The feasibility of estimating the mean pulmonary capillary pressure by simultaneous noninvasive recording of the ECG, the aortic and mitral valve echocardiogram was tested in 50 patients with miscellaneous heart lesions. The Q-MVC-/AVC-E ratio was measured from the onset of the QRS-complex in the ECG, the closure point of the aortic valve, the early diastolic opening of the anterior mitral valve (E-point) and the systolic closure of the mitral valve leaflets on the echocardiogram (C-point). A linear correlation exists between the mean pulmonary artery wedge pressure and the Q-MVC-/AVC-E ratio (n = 50, r = 0.75, p less than 0.001). The echocardiographic derivate index (Q-MVC-/AVC-E) is useful in assessing an elevated left ventricular filling pressure, but the individual data revealed variation in the predicted relation between Q-MVC-/AVC-E and left ventricular end-diastolic pressure. The Q-MVC-/AVC-E ratio is not a useful parameter in predicting left ventricular end-diastolic pressure in patients suffering from a left ventricular aneurysm or an acute transmural myocardial infarction with extensive regional abnormal wall motion. Many criteria such as mitral valve disease, atrial fibrillation, atrioventricular block and left bundle-branch block suggest that the Q-MVC-/AVC-E ratio is of limited clinical value. The left atrial emptying index was measured by using the amplitude of the posterior aortic wall motion occurring in the first third of the passive emptying period.(ABSTRACT TRUNCATED AT 250 WORDS)