| Abstract: |
Tissue Doppler echo is introduced (IDE) to quantify cardiac wall motion and it applies the Doppler principles to record tissue velocities. The blood moves at higher velocities compared with myocardium. IDE obtained by adjusting the ultrasound machine with low pass filter and low gain settings.The mitral annulus moves towards the apex during LV contraction and moves back toward the base during LV filling & left atrial filling. On the application of IDE on the mitral annulus, there are two positive waves of myocardial shortening recorded in systole; S I wave representingthe phase of isometric contraction & S 2 wave occurs due to ventricular shortening during L V ejection. Two negative waves of diastole Ea is that of isovolumic relaxation and Aa that of atrial contraction.During L V relaxation, Ca ++ ions, which induce contraction, when they are released into the cytoplasm, are taken up into the sarcoplasmic reticulum resulting in active relaxation of LV (elastic recoil).Mitral inflow is dependent on multiple interrelated factors, including rate, extent of ventricular relaxation, suction, atrial and ventricular compliance, mitral valve entrance and left atrial pressure. These factors have confounding effect on mitral inflow, L~ft atrial pressure and consequently PCWP. Among several Doppler measures, E/ A ratio & IVRT have significant relations with PCWP.We therefore attempted to correct for the effect of L V relaxation on IVRT by using T E-Iio time interval, based on onset of early transmitralannular wave but in impaired left ventricular filling the peak ofEa occurs after that of transmitral early diastolic velocity E.So patients with severe mitral stenosis were studied with conventional Doppler echo, IDE and estimate PCWP through equation:-IVRTPCWP= [0.9 x SBPJ x e32+0.7(TE_Ea)and PMBV was done and measure PCWP invasively by catheter pre and post PMBV as possible and LAP also measured as can as possible by right sided heart catheterization & compare the correlation between PCWP & conventional Doppler echo measures with PCWP & IDE measures correcting with IVRT (Doppler). Then, compare the estimated PCWP & measured PCWP pre PMBV and post PMBV .We found that several Doppler measures derived from mitral inflow are related well to PCWP including IVRT , E/A ratio and EDT.IVRT with T ii-Eo , IVRT with Tau are well related to PCWP formore characterization of PCWP to estimate it through the equation that depend on IVRT & Tau or IVRT & T E-EQ’can be easily obtained to estimate PCWP and the TDE modality becomes superior in estimating PCWP through the described equation.We concluded that ratio ofIVRTI T h-Ea and the ratio ofIVRT/Doppler derived Tau were more accurate than IVRT alone when correlated with PCWP. Accordingly, TOE might be a clinically applicable, noninvasive and accurate method for estimation of PCWP pre and post PMBV.
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