Measurement of Left Ventricular Ejection Fraction by Real Time 3D Echocardiography in Patients with Severe Systolic Dysfunction: Comparison with Radionuclide Angiography

AIM: Measurement of left ventricular ejection fraction (LVEF) using real time 3D echocardiography (3DE) has been performed in subjects with preserved or modestly reduced systolic function. Our aim was to evaluate this technique in the subset of patients with severe systolic dysfunction. METHODS AND RESULTS: Consecutive patients with LVEF less than 0.35 at two-dimensional echocardiography were included. LVEF obtained by 3DE was compared to the value measured by radionuclide angiography (RNA). Real time full-volume 3DE was performed, with offline semiautomated measurement of LVEF using dedicated software (Cardioview RT, Tomtec) by a single observer blinded to the results of RNA. A total of 50 patients were evaluated, of whom 38 (76%, 27 males, age 69 +/- 13 years) had a 3DE of sufficient quality for analysis. LVEF for this group was 0.21 +/- 0.07 using 3DE and 0.27 +/- 0.08 using RNA. The agreement between the two techniques was rather poor (r = 0.49; P < 0.001; 95% limits of agreements of -0.20 to 0.09). Truncation of the apex was observed in 6 of 38 (16%) patients. CONCLUSION: In patients with severe systolic dysfunction, 3DE shows poor agreement for measurement of LVEF as compared to RNA. There may be underestimation of up to 20% in absolute terms by 3DE. Accordingly, the two methods are not interchangeable for the follow-up of LV function. A limitation of 3DE may, at least in part, be related to the incomplete incorporation of the apical region into the pyramidal image sector in patients with dilated hearts.