Echocardiographic left ventricular volume determination by direct measurements of the major and minor axes.

Major and minor axes of the left ventricle were measured by single beam echocardiography in ten cardiac patients and the measurements and calculated volumes by formula V=pi/6 D2 were compared with the angiocardiographic estimates. There was a favorable correlation between echocardiographic and angiocardiographic major axis dimention (r=0.79), left end-diastolic volume (r=0.96), and ejection fraction (r=0.81). On the contrary, left end-diastolic volume calculated by formula V=D3 was less correlated with angiocardiographic estimates (r=0.93) and the former had a tendency to overestimate the volumes where D exceeded 6.5 cm. These data indicate that in cases with markedly enlarged left ventricle, the use of formula V=pi/6 D2L is a more accurate predictor of volumes than formula V=D3.