Echocardiographic assessment of ejection fraction in left ventricular hypertrophy

Objective-To investigate the value of Simpson's rule, Teichholz's formula, and recording of mitral ring motion in assessing left ventricular ejection fraction (EF) in patients with left ventricular hypertrophy. Design-Left ventricular ejection fraction calculated by Simpson's rule and by Techholt's formula and estimated by mitral ring motion was compared with values obtained by radionuclide angiography. Setting-Secondary referral centre. Patients-16 patients with left ventricular hypertrophy and a clinical diagnosis of hypertrophic cardiomyopathy or hypertension. Results-Calculation by Teichholz's formula overestimated left ventricular ejection fraction by 10% (p=0.002) and estimation based on mitral ring motion-that is, long axis measurements-underestimated ejection fraction by 19% (p = 0.002), without significant correlation between ring motion and ejection fraction. There was no significant difference between mean values of ejection fraction calculated by Simpson's rule and measured by the reference method, but a considerable scatter about the regression line with a standard error of the estimate of 9.3 EF%. Conclusions-In patients with left ventricular hypertrophy the ejection fraction, calculated by Teichholz's formula or Simpson's rule, is a poor measure of left ventricular function. When mitral ring motion is used for the assessment in these patients the function should be expressed in ways other than by the ejection fraction.