Evaluation of Left Ventricular Systolic Function by Tissue Doppler Imaging

Lee, Young Joo; Baek, Kwang Je; Lee, Kyeong Ryong; Hong, Dae Young; Kim, Jin Yong

Abstract

PURPOSE: Accurate determination of left ventricular ejection fraction (LVEF) is important in the emergency management of patients with cardiovascular disease. In 10% to 20% of patients, LVEF cannot be accurately determined by 2D echocardiography because of suboptimal endocardial definition on fundamental imaging. Measurement of mitral annular velocity is advantageous because it is not dependent on endocardial definition.
METHODS
One hundred fifty-four consecutive patients with acute dyspnea who visited our emergency medical center from September 2005 to March 2007 were prospectively recruited. Patients with atrial fibrillation, valvular disease and regional wall motion abnormality were excluded. Mitral annular peak systolic velocity was obtained from the medial site with apical 4-chamber view by pulsed wave tissue Doppler imaging. LVEF was calculated by modified Simpson's method for apical 4- and 2-chamber views.
RESULTS
The mean mitral annular peak systolic velocity was 7.2+/-1.8 cm/s (range 2.9 to 12.1), and the mean ejection fraction was 57.9+/-14.6% (range 17.9 to 83.9). The mitral annular peak systolic velocity correlated linearly with the ejection fraction (r=0.72, p<0.001): LVEF = 15+6 x mitral annular peak systolic velocity(%). The optimal cutoff value of mitral annular peak systolic velocity for identifyng LV systolic dysfunction (LVEF <55%) was 6.7 cm/s. At this cutoff value, the sensitivity, specificity, and accuracy were 84%, 85% and 85%, respectively. The area under the receiver operating characteristic curve was 0.91 (95% CI: 0.85-0.96). The intra-observer variability was +/-0.4 cm/s (3%) and the inter-observer variability was +/-0.6 cm/s (5%).
CONCLUSION
Simple measurement of mitral annular systolic velocity by pulsed wave tissue Doppler imaging can be easily applied to patient care and can be used to quantify LVEF accurately and with a high level of reproducibility.