P874Myocardial performance index in patients with left ventricular systolic dysfunction: conventional method versus Doppler tissue imaging


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Abstract

Background: Left ventricular systolic and diastolic dysfunction are the underlaying mechanisms of CHF. Isolated analysis of either mechanism may not be reflective of overall cardiac dysfunction. Myocardial performance (Tei) index has been described which may be more effective for analysis of global cardiac dysfunction than systolic and diastolic measures alone.Objectives: To compare myocardial performance index measured by conventional Doppler and myocardial performance index measured by Pulsed wave Doppler tissue imaging (PWDTI) in normal subjects and in patients with left ventricular systolic dysfunction.Patients & methods: The study comprised 50 patients with left ventricular ejection fraction (LVEF) < 50 % & 20 age & sex matched healthy volunteers as a control group. Conventional echocardiography was done to estimate LVEF by Simpson's rule and LV diastolic filling patterns by assessment of mitral inflow using pulsed wave Doppler (PWD) examination. Tei index was calculated conventionally by measurement of time intervals with PWD and with PWDTI as the average at the four mitral annular sites.Results: MPI was significantly higher in patients than control subjects both by conventional method (0.48±0.08 vs. 0.34±0.04, p <0.0001) & PWDTI (0.73±0.1 vs. 0.40±0.02, p <0.0001). MPI measured by PWDTI (MPI-DTI) showed a stronger negative & more significant correlation with LVEF than conventionally measured MPI in both control group (r = -0.7, p <0.001 & r = -0.47, p < 0. 05, respectively) and in patients group (r = -0.36, p < 0. 05 & r = -0.019, p > 0.05 respectively). The correlation between MPIDTI & MPI measured by conventional method was stronger in control group compared to patients group (r = 0.6, p < 0.05 & r = 0.035, p > 0.05, respectively). The cutoff points of MPI for prediction of LVEF < 50%, was (0.47 with 94% sensitivity & 90% specificity for MPIDTI) & (0.37 with 85% sensitivity & 84 % specificity for MPI measured by conventional method).Conclusion: PWDTI provides a simple, rapid, accurate & more reproducible tool for calculation of MPI in comparison to the conventional method. By overcoming the limitation of the conventional method, (MPI-DTI) is considered an effective tool for expression of LV function.

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