Estimation of left ventricular size by echocardiography.

A comparison of echocardiography with angiocardiography in estimating left ventricular dimensions was undertaken in ₅o patients. Angiographic data were derived from biplane Elema films, and echocardiography was used to measure the distance from the endocardial surface of the posterior wall of the left ventricle to the posterior surface of the interventricular septum. Left ventricular volume, calculated as the cube of the echo- cardiographic dimension, was related to that derivedfrom angiography (r= o 9I, standard error of the estimate 6i ml). In 32 patients, duplicate determinations of both angiographic and echocardiographic measurements were available, allowing the experimental error of each to be estimated. In this group, the echocardiographic dimension was shown to be similar in magnitude to, but not identical with, the mean minor axis measured by angiography. Lack offit between the two methods occurred in patients in whom left ventricular cavity shape was abnormal. There were also significant differences between the two measurements at end-systole and enddiastole, and between patients in atrialfibrillation compared with those in sinus rhythm. Comparison ofresidual values in the same patient between observed and predicted dimensions at end-systole and end-diastole showed a significant relation between the two.