Difference in the diastolic left ventricular wall motion velocities between aortic and mitral regurgitation by pulsed tissue Doppler imaging

Echocardiographic Assessment of Left Ventricular Function in Healthy Horses and in Horses with Heart Disease Using Pulsed-Wave Tissue Doppler Imaging

Background

Assessment of left ventricular (LV) function by tissue Doppler imaging (TDI) is not well established in horses with heart disease.

Objectives

To describe the use of pulsed‐wave (PW) TDI for the assessment of LV function, establish reference intervals, investigate effects of mitral regurgitation (MR), aortic regurgitation (AR), and primary myocardial disease (MD), and provide proof of concept for the use of PW TDI in Warmblood horses with heart disease.

Animals

Thirty healthy horses, 38 horses with MR, 25 with AR, 8 with MD.

Methods

Echocardiograms were retrospectively analyzed. Reference intervals were calculated. PW TDI indices of healthy horses and horses with MR, AR, and MD were compared by one‐way ANOVA and Dunnett's test.

Results

A complete set of PW TDI variables could be obtained in 94 of 101 horses. Variables corresponding to isovolumic intervals were most difficult to measure. Valvular regurgitation influenced variables describing isovolumic contraction and ejection. Horses with MD had significantly shortened ET_m (−118.5 [−154.1 to −82.9] ms; mean difference [95% CI of difference of means]), increased PEP_m/ET_m (0.11 [0.05 to 0.17]), prolonged IMP_m (0.28 [0.18 to 0.37]), increased S₁ (8.9 [5.2 to 12.6] cm/s), and decreased E₁ (−2.6 [−4.7 to −0.5] cm/s), E_m (−14.2 [−19.9 to −8.5] cm/s), and E_m/A_m ratio (−1.6 [−2.6 to −0.6]).

Conclusions and Clinical Importance

Pulsed‐wave TDI might be useful for detection of LV dysfunction in horses with primary MD. The clinical value of TDI in horses with MR and AR remains uncertain.

Dynamic myocardial velocity changes between phases of the cardiac cycle

The purpose of this study was 1. to define relationships between myocardial velocities according to phases and the range of dynamic phasic changes in controls using tissue Doppler echocardiography (TDE); 2. to compare the usefulness of dynamic changes vs. peak velocities alone on controls and patients. Peak velocity changes between phases were studied by colour M-mode TDE in the posterior wall from pre-ejection to systole (ejectional wall velocity increase) and from ejection to early diastole (early diastolic wall velocity increase) in 17 age-matched controls and a group of 30 patients with dilated cardiomyopathies (CMy) consisting of ischaemic (14) and nonischaemic (16) CMy with similar clinical and echocardiographic presentations. Systolic were correlated with early diastolic peak velocities (r = 0.79 p < 0.0001). Velocity values were significantly lower in patients than in controls (p < 0.001) as well as dynamic ejectional (p = 0.02) and early diastolic (0.03) increases. Dynamic changes were closely similar to controls (74 +/- 7%, 46 +/- 14%) in nonischaemic CMy (66 +/- 18%, 39 +/- 10% NS, respectively), but markedly reduced in ischaemic CMy (28 +/- 59%, and 26 +/- 31%, p = 0.005 and p = 0.06 vs. nonischaemic CMy, respectively). Of patients with ischaemic CMy, 78% had an ejectional increase < 40% and/or an early diastolic increase < 25%. Thus, correlation exists between systolic and early diastolic velocities. Normal range of dynamic changes was defined in an elderly population. Results suggest that velocity dynamics might be more informative than peak velocities alone to show left ventricular dysfunction.

Analysis of the myocardial velocities in patients with mitral stenosis

BACKGROUND

Pure mitral stenosis (MS) affects left-ventricular performance as a result of myocardial and functional factors. We planned this study to evaluate the effect of MS on right- and left-ventricular functions using Doppler tissue imaging (DTI).

METHODS

A total of 46 patients with an established diagnosis of MS (mean age: 41 +/- 11 years), and 40 age-matched healthy individuals (mean age: 40 +/- 9 years) were included in this study. Echocardiography equipped with DTI function was performed on each participant. The mitral valve area was measured. Myocardial velocities were recorded at 4 different sites (septum, lateral, anterior, and inferior) of the left ventricle, and the right-ventricular free wall annulus by DTI. The positive systolic velocity when the mitral and tricuspid ring moved toward the cardiac apex, and 2 negative diastolic velocities when the mitral annulus moved toward the base away from the apex (1 during the early phase of diastole and another in the late phase of diastole [A(m)]) were measured. The early diastolic velocity/A(m) ratio was calculated for each wall. The mean of systolic and diastolic myocardial velocities of the left ventricle was calculated. Patients with pure MS were compared with healthy participants, and the relationship of DTI variables with mitral valve area was evaluated.

RESULTS

The myocardial velocities of the left ventricle indicating left-ventricular function were found to be significantly lower in patients with pure MS. Right-ventricular annulus velocities, on the other hand, were similar in both groups. A significant positive correlation could be established between mitral valve area and mean positive systolic velocity, A(m) of the left ventricle, and right-ventricular A(m) (r = 0.50, P <.001; r = 0.48, P =.001; r = 0.45, P =.002, respectively), whereas a significant negative correlation (r = -0.42, P =.004) was established for right-ventricular early diastolic velocity/A(m) ratio.

CONCLUSION

This first study where pure MS was evaluated by DTI shows that MS affects left-ventricular performance on long axis. The results indicate that the decrease in left-ventricular performance is caused by both functional and myocardial factors.

Tissue Doppler imaging for the assessment of left ventricular systolic and diastolic functions

Doppler tissue imaging is a technique that allows recording of the low Doppler shift frequencies of high energy generated by the ventricular walls motion that are purposely filtered out in standard Doppler blood flow studies. Doppler tissue imaging can be performed with the use of pulsed Doppler, color two-dimensional Doppler, and color M-mode Doppler. Pulsed Doppler tissue imaging offers a high temporal resolution and therefore can be appropriately used for analysis of temporal relation between myocardium systolic and diastolic velocity waves. Color two-dimensional Doppler provides a good spatial resolution that permits differentiation of the velocity profiles between subendocardial and subepicardial layers but is limited by its poor temporal resolution. M-mode color-coded tissue imaging is characterized by a high spatiotemporal resolution, but sampling is only performed on a single line. Both two-dimensional and M-mode color-coded tissue imaging require specific modification of the current ultrasound machines. The present article reviews how Doppler tissue imaging may contribute to the noninvasive assessment of systolic and diastolic myocardial functions.

Alternative Echocardiographic Methods to Assess Left Ventricular Diastolic Function

The standard noninvasive method to assess left ventricular diastolic function has been pulsed Doppler echocardiographic recordings of mitral inflow early diastolic (E) and atrial (A) filling velocities and the ratio of E to A, in combination with isovolumic relaxation and deceleration times. Pulmonary venous inflow velocities (systolic, diastolic, and atrial reversal) are used to assess left atrial and left ventricular end-diastolic pressures. These measurements are influenced by changes in preload, including left ventricular end-diastolic pressure, left atrial or pulmonary capillary wedge pressure, and left ventricular volumes. Newer methods such as tissue Doppler imaging (TDI) of the mitral annulus and color M-mode recording of left ventricular diastolic flow propagation (FP) have now evolved as additional techniques for detecting abnormalities in left ventricular diastolic function that can complement the standard pulsed Doppler echocardiography methods. Both TDI and color M-mode flow FP appear to offer distinct advantages as relatively load-independent measures of diastolic function. TDI can be used for measurement of regional diastolic myocardial velocities at the mitral annulus, and it is particularly useful in identifying abnormalities of left ventricular diastolic relaxation or estimation of left ventricular filling pressures. Color M-mode FP can be used for quantification of abnormalities of left ventricular relaxation and diastolic filling characteristics of the left ventricle.

Tissue Doppler imaging: a useful echocardiographic method for the cardiac sonographer to assess systolic and diastolic ventricular function

Tissue Doppler imaging (TDI) has evolved to become a useful noninvasive method that can complement other echocardiographic techniques in the assessment of left ventricular myocardial velocities in a variety of clinical conditions. Color 2-dimensional and color M-mode TDI are used for quantification of systolic myocardial velocities during myocardial ischemia at rest and with pharmacologic stress testing. Spectral pulsed TDI can provide measurements of regional systolic and diastolic myocardial velocities, and it is particularly useful in the identification of abnormalities of left ventricular diastolic relaxation. This review summarizes the clinical applications of TDI to promote understanding of its utility in the evaluation of left ventricular myocardial function.

In vitro validation of tissue Doppler left ventricular regional wall velocities by using a novel balloon phantom

To investigate the validity and accuracy of tissue Doppler imaging (TDI) using a novel balloon phantom, validation of TDI myocardial velocity measurements has been carried out indirectly from conventional M-mode images. However it is not a true and independent gold standard. We described a new TDI validation method by using a specially developed left ventricular balloon model mounted in a water bath and constructed using two pear-shaped balloons. It was connected to a pulsatile flow pump at 8 stroke volumes (50-85 ml/beat). The displacement and velocity of the balloon walls were recorded simultaneously by video imaging and TDI on a GE-Vingmed System Five with a 5 MHz phased array probe at the highest frame rates available. Conventional M-mode and 2-D imaging verified that our balloon model mimicked the shape and wall motion of left ventricle. There was a good correlation and agreement between the maximum video excursion of the anterior and posterior walls of the phantom and the results of the temporal integration of digital distance data by TDI (Anterior wall: r = 0.97, SEE = 0.24 mm, mean +/- s = 0.04 +/- 0.24 mm; Posterior wall: r = 0.95, SEE = 0.22 mm, mean +/- s = 0.03 +/- 0.24 mm). Analysis of the velocity profile by the TDI method showed that the velocity at each measured point was correlated well with the velocity obtained from the video images (Anterior wall: r = 0.97, SEE = 0.30 mm, mean +/- s = -0.04 +/- 0.28 mm; Posterior wall: r = 0.97, SEE = 0.30 mm, mean +/- s = 0.04 +/- 0.28 mm). Our balloon model provided a new independent method for the validation of TDI data. This study demonstrated that the present TDI system is reliable for measuring wall motion distance and velocity.