Measuring Tei Index For Assessing Left Ventricular Function In Patients With Myocardial Infarction By Tissue Doppler Imaging

Background And Objective Tei index, which is also named myocardial performance index, is a new Doppler index applied to the evaluation of the whole function of heart. In the animal experiments and human's clinical studies, Tei index is closely correlated with other parameters, such as cardiac output, left ventricular ejective fraction(LVEF), +dp/dt, -dp/dt, etc. Moreover, it is known to be independent of both ventricular geometry and heart rate. At present, Tei index has been gained by blood flow Doppler imaging and can't be measured in one cardiac period. Tissue Doppler imaging (TDI) could overcome the backward of the conventional method. In this study, we evaluated the applicability and usefulness of pulsed-wave tissue Doppler imaging (TDI) as a tool to calculate Tei index. Tei index was measured by TDI in 30 patients with myocardial infarction (MI group) and 48 healthy subjects, comparing with the parameters of left ventricular function from Isotope-angiography. The purposes of this study were: ①To seek the magnitude of the Tei index with TDI in health subjects of different age groups and to analyze the correlation between age and Tei index; ② To compare Tei index by TDI with the parameters of left ventricular systolic function from TDI and Isotope angiography and blood pool imaging in order to assess the feasibility and reliability of Tei index in evaluating left ventricular function.Materials And Methods Thirty MI patients (MI group) and 48 normal persons (NP)were studied with GE-vivid7 ultrasound system. The heart rate, blood pressure and usual echocardiograph parameters of all studied subjects were recorded at rest. The normal subjects were divided into three groups. The echocardiographic parameters include :(D LVEF measured by Simpson's method. (2) Tei index measured by pulse blood Doppler, Tei index was defined as (a-b)/b. a was the interval between end and onset of the mitral inflow, and b was the ejection time of aorta. Tei index by the conventional method was defined as c-Tei. (3) By TDI, a and b, displacements were measured at six different sits in the mitral annulus: posterior septum and lateral wall (apical four chamber views), inferior and anterior wall (apical two chamber views), anterior septum and posterior wall (apical long-axis views). The global left ventricular values were calculated by dividing the sum of these values into six. Mean Tei index by TDI was defined as t-Tei. All MI patients took multiple gated cardiac blood pool imaging examination to obtain LV global ejection fraction (ECT-EF), regional ejection fraction (REF) and peak filling rate (PFR).Results(D The value of t-Tei in the health group was 0.39±0.02,there were not different in six sits of mitral annulus and not different in different ages (p>0.05). There were not different between conventional Tei index and t-Tei(p>0.05).?The value of t-Tei index in the MI group was longer than the health group (0.80±0.29 vs 0.39±0.02,p<0.001), and there are different t-Tei values in different walls ofMI (p<0.05)o(Din all involved, there was a significant correlation between t-Tei and c-Tei( NP: r=0.846,p<0.001; MI: r=0.899,p<0.01)? Meanwhile, the correlation of t-Tei with LVEF(r=-0.797,p<0.001), displacement of mitral annulus (r=-0.475,p<0.05), the correlation of t-Tei with ECT-EF, PFR and the correlation of the regional t-Tei index with REF were good (p<0.01).Conclusion(D The magnitude of the Tei index with TDI in health subjects was 0.32-0.46, the mean value was 0.39±0.02, there were not different in different ages and not differentbetween c- Tei index and t-Tei.(2) The value of t-Tei index in the MI group was longer than the health group, and there are different t-Tei values in different walls of MI. The t-Tei index values at the mitral annulus sits corresponding with MI walls were longer than other sits.?There was a significant correlation between t-Tei and c-Tei. Meanwhile, the correlation of t-Tei with LVEF, displacement of mitral annular, the correlation of t-Tei with ECT-EF, PFR and the correlation of the regional t-Tei index with REF was good. It was indicated that t-Tei index measured by TDI could evaluate left ventricular global function and t-Tei index of different walls could evaluate left ventricular regional systolic function in some degrees. There are clinical applications in evaluating left ventricular global and regional function correctly using Tei index by Tissue Doppler imaging.