Estimation of rate of left ventricular pressure rise by Doppler echocardiography: its hemodynamic validation

A New Echocardiographic Index for Assessing Left Ventricular Function and Mechanism of Mitral Regurgitation and Its Relation to Other Echocardiographic Indices

OBJECTIVE

Mitral regurgitation (MR) is a progressive disease of the mitral valve, which can be primary or functional. The assessment of left ventricular function in MR is still troublesome. In this study, we evaluated the validity of a new parameter, total dt, in patients with MR.

METHODS

Forty patients with severe MR constituted the study group. According to the transesophageal echocardiographic evaluation, the patients were dichotomized into two groups: (1) Primary MR; n = 21, (2) Functional MR; n = 19. The total dt was defined as the sum of time intervals from 1 msto 3 ms (positive dt) and from 3 ms to 1 ms (negative dt) on the CW Doppler recording of MR jet. It was compared to other indices of left ventricular function and left ventricular geometry, including ejection fraction, fractional shortening, myocardial performance index, coaptation distance, left ventricular volume and diameter, sphericity index, and parameters of diastolic function.

RESULT

The total dt correlated with myocardial performance index, coaptation distance, and sphericity index. It could differentiate between primary and functional MR with an area under curve of 0.878, followed by myocardial performance index with 0.860. The total dt > 104 ms was 79% sensitive and 81% specific for discrimination.

CONCLUSION

The total dt is useful for assessing left ventricular function and also for differentiating primary MR from functional MR.

Noninvasive assessment of left ventricular isovolumic contraction and relaxation with continuous wave Doppler aortic regurgitant velocity signals: an in vivo validation study

The purpose of this study was to provide fundamental in vivo validation of a method with the use of aortic regurgitant (AR) jet signals recorded with continuous wave (CW) Doppler for assessing left ventricular (LV) isovolumic contraction and relaxation. Preliminary studies have suggested that analysis of CW Doppler AR velocity signals permits the estimation of LV positive and negative dP/dt. We studied 19 hemodynamically different states in 6 sheep with surgically induced chronic aortic regurgitation. CW AR velocity spectra and high-fidelity LV and aortic pressures were recorded simultaneously. Rates of LV pressure rise and fall (RPR and RPF) were calculated by determining the time interval between points at 1 m/s and 2.5 m/s in the deceleration and acceleration slopes of the CW Doppler AR velocity envelope (corresponding to a pressure change of 21 mm Hg). RPR and RPF calculated by CW Doppler analysis for each state were compared with the peak positive dP/dt and negative dP/dt, obtained from the corresponding high-fidelity LV pressure curve, respectively. The LV peak positive and negative dP/dt derived by catheter ranged from 817 to 2625 mm Hg/s and from 917 to 2583 mm Hg/s, respectively. Multiple regression analysis showed that Doppler RPR correlated well with catheter peak positive dP/dt (r = 0.93; mean differences, -413 +/- 250 mm Hg/s). There was also good correlation and agreement between Doppler RPF and the catheter peak negative dP/dt (r = 0.89; mean difference, -279 +/- 239 mm Hg/s). Both Doppler-determined RPR and RPF underestimated their respective LV peak dP/dt. CW Doppler AR spectra can provide a reliable noninvasive estimate of LV dP/dt and could be helpful in the serial assessment of ventricular function in patients with aortic regurgitation.

Rates of left ventricular isovolumic pressure rise and fall from the aortic regurgitation velocity signal: description of the method and validation in human beings

BACKGROUND

Aortic regurgitation results from a pressure gradient across the aortic valve during left ventricular (LV) isovolumic relaxation, LV filling, and isovolumic contraction periods. Assuming the applicability of the simplified Bernoulli equation to this pressure-flow relation and constancy of aortic pressure during LV isovolumic relaxation and contraction periods, one can theoretically obtain estimates of the rates of LV isovolumic pressure fall and rise (deltaP/delta t) from the aortic regurgitation (AR) velocity signal.

METHODS AND RESULTS

Mitral regurgitation (MR) and AR signals were recorded by using the continuous wave Doppler technique in 26 patients with combined mitral and aortic regurgitant lesions. The LV negative deltaP/delta t was obtained by dividing the time taken for the AR velocity to rise from 1 m/sec to 2.5 m/sec into 21 mm Hg, which is the estimated LV pressure drop between these points. In a similar fashion, the LV positive deltaP/delta t was obtained between 2.5 m/sec and 1 m/sec of the fast decelerating portion of the AR signal. The LV negative deltaP/delta t by the AR method ranged from 420 to 3500 mm Hg/sec and correlated well with that obtained by the MR method obtained in a blinded fashion (r = 0.95, p < 0.0001). The mean (SD) difference between the two methods was 30 (129) mm Hg/sec. Similarly, the LV positive deltaP/delta t by the AR method (range 420 to 2625 mm Hg/sec) correlated closely with that obtained by the MR method (r = 0.93, p < 0.0001), with the mean (SD) difference between the two methods being 38 (138) mm Hg/sec.

CONCLUSIONS

Preliminary data presented in this study indicate the feasibility of obtaining a reliable estimate of LV positive and negative deltaP/delta t from the AR velocity profile. Thus the examination of the AR signal may give valuable insights into both LV systolic and diastolic functions.

Accurate noninvasive estimation of left ventricular end-diastolic pressure: comparison with catheterization

We evaluated the accuracy of a new Doppler-based method using the mitral regurgitant velocity at the time of aortic valve opening for the noninvasive estimation of left ventricular end-diastolic pressure. Sixty unselected patients were studied immediately before routine catheterization. Invasive left ventricular end-diastolic pressure was obtained using a fluid-filled pig-tail catheter. Noninvasive estimation of left ventricular pressure at aortic valve opening was taken as systemic diastolic pressure using an automated cuff. Noninvasive left ventricular end-diastolic pressure was calculated as diastolic blood pressure--4 x (mitral regurgitant velocity at aortic opening)2. Those making noninvasive determinations were blinded to catheterization results. An adequate mitral regurgitant Doppler recording was obtained in 24 patients (40%). In patients with a left ventricular end-diastolic pressure greater than 15 mm Hg the yield was 65%. Left ventricular end-diastolic pressures ranged from 4 mm Hg to 30 mm Hg. Bland and Altman analysis revealed no systematic bias and close agreement was found, with individual discrepancies not exceeding 5 mm Hg.

Newer Doppler measures of left ventricular diastolic function

Left ventricular (LV) diastolic dysfunction is an important cause of heart failure, and recent advances in the application of Doppler techniques allow a semiquantitative assessment of LV diastolic performance. This review discusses the use of Doppler echocardiography in the comprehensive assessment of LV diastolic function and performance in terms of the normal mitral and pulmonary venous flow profiles, their physiologic basis, and alterations in diseased states. There is also a discussion on the newer aspects of mitral flows such as relative durations of mitral A and pulmonary vein AR waves, E- and A- wave propagation inside the LV with their hemodynamic correlates, and derivation of ventricular dP/dt and Tau from the mitral regurgitation velocity profile. Analysis of these flow profiles and the other Doppler measures alluded to above allow one to make a fairly precise hemodynamic assessment of a patient in terms of left atrial pressure, LV relaxation and stiffness and the profile of LV diastolic pressure in terms of pre- 'a' wave and 'a' wave pressures and ventricular end-diastolic pressure.