Myocardial longitudinal motion by tissue velocity imaging in the evaluation of patients with myocardial infarction

Cardiac remodeling in patients with primary aldosteronism

OBJECTIVE

To evaluate the morpho-functional changes of the myocardium in patients with primary aldosteronism (PA).

DESIGN

An observational study in a university referral center for blood pressure diseases.

PATIENTS

Twenty- three patients with PA, 24 patients with essential hypertension (EH), and 15 normotensive controls (C) underwent conventional echocardiography with integrated backscatter (IBS) and tissue Doppler imaging (TDI) analysis. The corrected IBS (C-IBS) values and the systo-diastolic variation of IBS (CV-IBS) were performed at both interventricular septum and the posterior wall levels. TDI myocardial systolic (Sm), early diastolic (Em), and late diastolic (Am) velocities of both left ventricular walls were also determined.

RESULTS

In PA patients, septal and posterior wall CV-IBS were significantly lower than C (p<0.0001) and EH patients (p<0.001). In EH, CV-IBS was significantly lower than C (p<0.001). Patients with PA exhibited lower Sm, lower Em, and higher Am, and a subsequently reduced Em/Am ratio than C (p<0.001 for all) and EH (p<0.01 for all) at interventricular septum and lateral wall levels. In the latter, Sm, Em, and Em/Am ratio were lower and Am was higher than C (p<0.001 for all). In PA and EH patients, CV-IBS at both septum (r=-0.66, p<0.001) and posterior wall levels (r=-0.67, p<0.001) and Sm peak of both septum (r=-0.52, p<0.001) and lateral wall (r=-0.55, p<0.001) were inversely related to plasma aldosterone.

CONCLUSIONS

Patients with PA showed myocardial wall remodeling characterized by increased myocardial fibrosis and early left ventricular systodiastolic function abnormalities.

Sample volume positioning in colour-coded Doppler myocardial imaging: effect of systolic and diastolic tracking

To date, Doppler myocardial imaging (DMI) is no longer an intriguing new research tool only, but is rather on the verge of becoming a routinely used diagnostic method in adult and pediatric cardiology. Clinical studies have proven its diagnostic relevance for global left and right ventricular function. Concerns about reliability and reproducibility of DMI functional analysis, however, rely on lacking standards for the acquisition and analysis of DMI parameters. This study focuses on the effect of sample volume positioning during the cardiac cycle on the absolute myocardial velocities. Our hypothesis was that systolic sample volume placement leads to altered diastolic measurements, and diastolic placement vice versa to altered systolic measurements, when compared with continuous systolic and diastolic tracking. The effect of tracking on intra- and interobserver variability was a second endpoint of the study. Twenty healthy women underwent color-coded Doppler myocardial imaging. Clips of three heart cycles were stored in digital format for off-line analysis, administering sector angles of approximately 30 degrees and a mean frame rate of 280 frames per second. Using the Echopac software (GE, Germany), the sample volume was positioned immediately below the atrioventricular valvar annulus within the basal segments of the right and left ventricular free wall and the interventricular septum. Three conditions were investigated: conventional end-systolic or end-diastolic placement of the Doppler probe, or continuous tracking to the ideal position during systole or diastole. Descriptive statistics, intra and interobserver variabilities and Bland-Altman analyses were performed. Tracking revealed higher values of early diastolic myocardial velocities compared with measurements during systolic sample volume placement only, and higher systolic myocardial velocities, preejection acceleration and late diastolic myocardial velocities using diastolic sample volume placement. Inter and intraobserver reproducibility improved remarkably with the new procedure with the exception of isovolumic acceleration (IVA), which could not be reproduced satisfactorily at all. In summary, tracking is a promising method that helps to improve reproducibility of DMI-derived myocardial velocities. It helps to minimize the effect of changing myocardial velocities during the natural longitudinal cardiac movement, and should be considered as standard method during DMI.

Autonomic modulation and cardiac contractility in vasovagal syncope

BACKGROUND

Previous studies proposed as one of the main mechanisms involved in neurally mediated syncope, the stimulation of ventricular mechanoreceptors as the final trigger for vagal discharge.

OBJECTIVES

This study aimed to verify the presence of a sympathetic driven increase of cardiac contractility before vasovagal syncope.

METHODS

We studied 23 patients with recurrent syncope. All underwent a 60 ° tilt with pharmacologic challenge (sublingual spray nitrate). Two conditions were used to assess autonomic activity by heart rate variability analysis: in a supine position after 5 min of rest and after 15 min of tilt. Simultaneously, cardiac contractility was quantified by tissue-Doppler echocardiography at the base of the free walls of left ventricle. The peak myocardial velocities during systole (Sw) and late diastole (Aw) were considered.

RESULTS

Passive tilt induced a significant increase of the low frequency component (LF) as well as a decrease of the high frequency component (HF) in positive patients (LF: from 49 ± 18 to 65 ± 18 nu, p<0.05; HF: from 41 ± 21 to 26 ± 16 nu, p<0.05). Tissue-Doppler showed a similar increase in Sw in both positive and negative patients but showed a significant decrease of Aw in syncopal subjects (p<0.005).

CONCLUSIONS

Our results do not show an increase in ventricular contractility before tilt-induced syncope, or in presence of a valuable increase of sympathetic activity. Instead, we observe a reduction of atrial contractility, which may be a contributory component in the pathogenesis of vasovagal syncope.

Severe tricuspid regurgitation shows significant impact in the relationship among peak systolic tricuspid annular velocity, tricuspid annular plane systolic excursion, and right ventricular ejection fraction

OBJECTIVES

Peak systolic mitral annular velocities correlate with left ventricular ejection fraction (EF) regardless of mitral regurgitation severity. Peak systolic tricuspid annular velocity (RV-Sm) and tricuspid annular plane systolic excursion (TAPSE) are used to assess right ventricular (RV) EF (RVEF). We investigated whether tricuspid regurgitation (TR) affects the relationship among RV-Sm, TAPSE, and RVEF.

METHODS

Patients (n = 625) underwent echocardiography and Doppler tissue studies. Left ventricular EF and RVEF were estimated by Simpson's rule. Because of confounding, we excluded patients with diseases that influence mitral annular motion or left ventricular function. We finally enrolled 225 patients: 125 with mild TR, 50 with moderate TR, and 50 with severe TR. Forty study patients (20 with mild TR, 10 with moderate TR, and 10 with severe TR) received radionuclide ventriculography.

RESULTS

The RVEF estimated by Simpson's method correlated strongly to that estimated by the radionuclide method (r = 0.793, r2 = 0.629, P < .0001). With mild or moderate TR, RV-Sm correlated well to RVEF (mild TR group: r = 0.765, r2 = 0.59, P < .0001; moderate TR group: r = 0.756, r2 = 0.57, P < .0001). RV-Sm had no significant correlation to RVEF in patients with severe TR (r = 0.212, r2 = 0.05, P = .167). Over a range of TR severities, the relationship between TAPSE and RVEF showed a similar trend to that between RV-Sm and RVEF.

CONCLUSION

Severe TR has a significant impact on the relationship between RV-Sm and RVEF and between TAPSE and RVEF. TAPSE and RV-Sm in patients with severe TR show poor correlation to RVEF. When applying Doppler tissue method or TAPSE to assess RV function, severe TR is a significantly confounding factor.

Right Heart Function in Scleroderma: Insights from Myocardial Doppler Tissue Imaging

To use Doppler tissue imaging to evaluate heart function and to predict rehospitalization rate in progressive systemic sclerosis, we studied 40 patients (limited in 24 patients, diffuse in 16 patients) with chest roentgenography, pulmonary function test, routine echocardiography, and myocardial Doppler tissue. Another 45 volunteers without any sign of heart failure served as the control group. Significant difference of echocardiographic parameters was found in peak transmitral early diastolic velocity, right ventricular (RV) ejection fraction (EF) (RVEF), pulmonary artery systolic pressure, and Doppler tissue parameters of the RV and septum (peak transmitral early diastolic velocity, P = .012; RVEF, P < .0001; pulmonary artery systolic pressure, P < .0001). The parameters derived by pulsed wave Doppler tissue decreased in RV, including peak systolic myocardial velocity (Sm), early diastolic velocity, late diastolic velocity, and myocardial performance index. RVEF and left ventricular EF were estimated by Simpson's method. RV-Sm could be used to identify RV failure. Receiver operating characteristic area under the curve for RV-Sm was 0.935. RV-Sm less than 11 cm/s indicted RVEF less than 40% with sensitivity of 87% and specificity of 86%. Contrary to expectation, pulmonary artery systolic pressure was not so well correlated with RV function. The frequency of admission was reverse correlated with decrement of RV-Sm in patients with RV-Sm less than 12 cm/s. We conclude that in progressive systemic sclerosis, RV systolic dysfunction is common and appears to be a result of pulmonary hypertension, disturbance of myocardial microcirculation, and myocardial fibrosis. Pulmonary hypertension was not well correlated with RV dysfunction; it suggested pulmonary hypertension was not the only cause of RV failure. Primary right heart involvement was the other possible cause. By myocardial Doppler tissue imaging, we can predict the frequency of hospitalization; it suggests simultaneous involvement of heart, skin, lung, and other organs. RV-Sm more than 12 cm/s predicted a decreased likelihood of readmission to the hospital.

Contribution of decreased atrial function in the pathogenesis of neurally mediated syncope

One of the most important mechanisms proposed in the pathogenesis of neurally mediated syncope considers the stimulation of myocardial mechanoreceptors as the final trigger leading to reflex hypotension and bradycardia. The aim of our study was to analyze the modifications of systolic and diastolic velocities of the left ventricle by tissue Doppler echocardiography, during the upright tilt test, to confirm the presence of an increased ventricular contractility before syncope. We evaluated 47 patients (mean age 43 years) with unexplained syncope and 13 healthy subjects. Three echocardiographic recordings were collected: at baseline, during the initial 5 minutes of the test, and after 15 minutes of tilt. The upright tilt test was positive in 28 patients. During the test, all of them had a similar, significant, progressive reduction of left ventricular end-diastolic volume, left atrial area, and left atrial volume. In contrast, the left ventricular ejection fraction showed an early, more pronounced decrease in those with positive tests. By tissue Doppler echocardiography, the systolic waves remained almost unchanged, and the early filling waves decreased similarly in those with positive or negative findings and the controls. In contrast, the atrial filling waves showed a significant decrease only in patients with positive tests. In conclusion, our study did not find increased ventricular contractility before syncope. In contrast, a decreased atrial contribution to ventricular filling characterized patients with positive upright tilt test results, which, we postulate, may be an important contributory factor to vasovagal syncope.

Right Heart Function in Systemic Lupus Erythematosus: Insights from Myocardial Doppler Tissue Imaging

The purpose of this study was to use Doppler tissue imaging to evaluate heart function and to investigate the correlation between Doppler imaging and pulmonary artery systolic pressure (PASP) and right ventricular (RV) ejection fraction (EF) in patients with systemic lupus erythematosus (SLE). Standard echocardiography and 2-dimensional and color Doppler imaging were used to assess cardiac function in patients given the diagnosis of SLE (n = 40) and healthy control subjects (n = 45). Half of the patients with SLE also presented with pulmonary hypertension (PH). Significant differences in PASP and RV EF (RVEF) were found between the control and SLE groups. The peak systolic velocity of tricuspid annulus was significantly lower in patients with SLE than in the control group. The calculated myocardial performance index of the RV, septum, and left ventricular lateral wall were significantly higher in patients with SLE than in the control group. Bivariate correlation analysis revealed a significant correlation among PASP, RVEF, and systolic tricuspid annular velocity. There was a significant correlation between each of these 3 parameters and the 6-minute walk distance in patients with SLE. Patients with SLE and PH had a significantly shorter 6-minute walk distance than patients with SLE without PH. Furthermore, in patients with SLE and PH, RVEF and systolic tricuspid annular velocity were lower than in the control subjects and patients with SLE without PH. Patients with SLE and PH had a longer isovolumic relaxation time and a higher myocardial performance index of RV than those without PH. Finally, by simple linear regression analysis, we found a significant positive relation between RVEF and systolic tricuspid annular velocity, but a negative relationship between PASP and systolic tricuspid annular velocity. These findings demonstrate that in patients with SLE, systolic tricuspid annular velocity determined by echocardiography and Doppler imaging can be used to assess RV function and PASP. Furthermore, systolic tricuspid annular velocity reflects exercise tolerance in patients with SLE and the length of the isovolumic relaxation time represents the progression of PH.

Early detection of cardiac dysfunction in patients with anorexia nervosa by tissue Doppler imaging

BACKGROUND

Cardiac damage is a major complication of chronic starvation. The aim of this study was to evaluate the changes of left ventricular function in patients with anorexia nervosa by means of pulsed tissue Doppler imaging.

METHODS

A total of 20 females (age 22.4+/-4.3 years) with overt anorexia nervosa, 20 matched healthy thin females with body mass index < 19 kg/m2 and 20 matched healthy normal-weight females underwent both standard echocardiography and tissue Doppler imaging. Myocardial systolic wave (Sm) and early (Em) and atrial (Am) diastolic waves were measured on the basal lateral segment and the basal interventricular septum from the apical four-chamber view.

RESULTS

When compared with control groups, the anorexia nervosa group showed lower left ventricular mass (p < 0.0001), lower Sm peak of both lateral wall (6.5+/-0.9 vs. 9.4+/-2.1 and vs. 9.5+/-1.9 cm/sec, p < 0.001) and septum (5.6+/-1.5 vs. 8.6+/-1.6 and vs. 8.8+/-1.5 cm/sec, p < 0.001), and comparable Em, Am and Em/Am ratio. The ratio between transmitral peak E and Em was significantly greater in anorexic patients than in controls (lateral wall: 8.1+/-0.1 vs. 6.8+/-0.2 and vs. 6.9+/-0.2, p < 0.001; septum: 10.8+/-0.4 vs. 8.8+/-0.5 and vs. 8.8+/-0.3, p < 0.001). No differences were observed between thin and normal-weight females. In the anorexia nervosa group, S(m) peak was significantly related to left ventricular mass indexed, at both septum (r = 0.55, p < 0.02) and lateral wall (r = 0.49, p < 0.03) levels.

CONCLUSIONS

These results show that anorexia nervosa is associated with left ventricular systolic dysfunction, which is related with the reduction of cardiac mass. Tissue Doppler imaging can give useful information in the identification of regional left ventricular dysfunction, in addition to traditional parameters.

Feasibility of color doppler tissue velocity imaging for assessment of regional timing of left ventricular longitudinal movement

OBJECTIVE--The feasibility of color Doppler tissue velocity imaging (c-TVI) with a high time resolution of 10 ms for simultaneous measurement of the temporal characteristics of regional left ventricular (LV) tissue velocities at different LV sites was examined. Methods and results--In 20 subjects with structurally normal hearts, inter- and intraobserver agreement and the beat-to-beat variation were tested in c-TVI profiles from basal and mid-LV segments of the interventricular septum (IS) and of the lateral free wall (LFW). For peak tissue velocities a mean error of less than 1 cm/s was demonstrated. For systolic regional LV velocity time difference, the mean error was +/- 5 ms, with the best agreement when sampling from basal LV sites. For diastolic regional LV velocity time differences, the mean error was +/- 12 ms. The longitudinal LV movement pattern demonstrated a pattern of incremental tissue velocity from basal to mid-LV, and from IS to LFW sites. Conclusion--The c-TVI method has acceptable inter- and intraobserver agreement and is sufficiently accurate to disclose regional time aspects of LV contraction and relaxation.

Distribution of left ventricular longitudinal peak systolic strain and impact of low frame rate

The myocardium has complex 3-D motion that is frequently described using ultrasound (US) Doppler techniques that are limited to recording velocities in one dimension only. Studies using 3-D tagged magnetic resonance show that the myocardium has strain components with varying angles throughout the myocardium. Despite this, there seems to be a belief that the left ventricular longitudinal strain distribution should be homogeneous. When measuring myocardial strain, there are several parameters for the clinician to decide on, one of them being recording frame rate. The current study aims to further investigate the alleged homogeneity of the longitudinal myocardial strain distribution and to discover the impact that the frame rate has on these measurements. Myocardial strain was measured in 43 healthy individuals at different frame rates. Analysis of variance results clearly demonstrate that the strain is not uniformly distributed over the wall; there seems to be an increasing strain from apex toward the base. However, subjects exist with different distributions; thus, it is not possible to conclude that certain strain patterns are normal. Reduced frame rate had a highly significant impact on the measured strain results and it is seen that, at low frame rates, the strain values were reduced.

Instantaneous assessment of left ventricular midwall mechanics with tissue Doppler tracking technique

BACKGROUND

Left ventricular (LV) systolic function is better characterized by midwall mechanics in patients with LV hypertrophy than by endocardial LV function, and the midwall mechanics is an independent predictor of prognosis. However, a complex calculation is currently required to assess it, and it is not routinely assessable in clinical practice. Tissue Doppler imaging enables tracking of a point within the LV wall though a cardiac cycle; we tested our hypothesis that the tissue Doppler tracking technique provides an instantaneous and reliable evaluation of midwall mechanics.

METHODS

LV M-mode echocardiogram was recorded in 18 subjects with conventional echocardiography and with tissue Doppler imaging. The midwall shortening was calculated from the data obtained with conventional echocardiography for the comparison with that measured with the tissue Doppler tracking technique. The tissue Doppler-determined midwall shortening correlated well with conventionally calculated value (r=.84, P<.0001), and their difference was small irrespective of absolute value of the midwall shortening.

CONCLUSIONS

The midwall mechanics can be instantaneously and accurately evaluated with the tissue Doppler tracking technique.

Application of tissue Doppler imaging in cardiology

Tissue Doppler imaging (TDI) is a new echocardiographic technique employing the Doppler principle to measure the velocity of myocardial segments and other cardiac structures. It is well suited for the measurement of long-axis ventricular function. Impairment of longitudinal myocardial fiber motion is a sensitive marker of early myocardial dysfunction and ischaemia, and TDI might therefore become an important tool in routine echocardiography. The technique allows truly quantitative measurement of regional myocardial function both at rest and during stress echocardiography. TDI has great potential in the diagnosis of diastolic left ventricular dysfunction, overcoming the load-dependence of conventional Doppler techniques. Right ventricular function, intracardiac and pulmonary artery pressures, transplant rejection and intraventricular dyssynchrony can also be assessed. This article reviews the current and evolving applications of TDI in cardiology.

Tissue Doppler, strain, and strain rate echocardiography for the assessment of left and right systolic ventricular function

Tissue Doppler (TDE), strain, and strain rate echocardiography are emerging real time ultrasound techniques that provide a measure of wall motion. They offer an objective means to quantify global and regional left and right ventricular function and to improve the accuracy and reproducibility of conventional echocardiography studies. Radial and longitudinal ventricular function can be assessed by the analysis of myocardial wall velocity and displacement indices, or by the analysis of wall deformation using the rate of deformation of a myocardial segment (strain rate) and its deformation over time (strain). A quick and easy assessment of left ventricular ejection fraction is obtained by mitral annular velocity measurement during a routine study, especially in patients with poor endocardial definition or abnormal septal motion. Strain rate and strain are less affected by passive myocardial motion and tend to be uniform throughout the left ventricle in normal subjects. This paper reviews the underlying principles of TDE, strain, and strain rate echocardiography and discusses currently available quantification tools and clinical applications.

Longitudinal ventricular function: normal values of atrioventricular annular and myocardial velocities measured with quantitative two-dimensional color Doppler tissue imaging

OBJECTIVE

Quantitative 2-dimensional color Doppler tissue imaging is a new method to reveal impairment of left ventricular (LV) and right ventricular (RV) longitudinal function, which is a potential marker of early myocardial disease. The aim of this study was to obtain normal values for atrioventricular annular and regional myocardial velocities using this method.

METHODS

A total of 123 healthy patients (age range: 22 to 89 years) underwent echocardiography including color Doppler tissue imaging using a scanner (Vivid 5, GE Vingmed, Horten, Norway) with postprocessing analysis (Echopac 6.3, GE Vingmed). Regional myocardial velocities were measured at 12 LV segments in 3 apical views and 2 segments of the free RV wall. Mitral annular velocities from 6 sites, and tricuspid annular velocities at its lateral site, were also assessed. At each site, systolic (S(m)), early diastolic (E(m)), and late diastolic (A(m)) velocities were measured, and the E(m)/A(m) ratio was calculated.

RESULTS

Patients were classified into 4 groups aged 20 to 39, 40 to 59, 60 to 79, and >/=80 years. Mitral annular velocity and regional LV myocardial S(m) and E(m) progressively decreased with age. A(m), whereas low in the youngest age group, increased significantly in patients more than 40 years of age. The E(m)/A(m) ratio gradually declined with aging. There were no differences between age groups in S(m) measured at the tricuspid annulus and free RV wall, but the pattern of age-related changes of diastolic velocities and E(m)/A(m) ratio was the same as in the LV. Slight but significant sex-related differences were observed in middle-aged groups. The intraobserver and interobserver reproducibility was highest for atrioventricular annular velocities.

CONCLUSIONS

A progressive decrease in S(m) reveals a decline in longitudinal systolic LV function with age, whereas systolic RV function remains unaffected. Atrioventricular annular velocity and regional E(m) decrease with aging in both ventricles, suggesting a deterioration in the diastolic properties of the myocardium, whereas A(m) increases from middle age implying a compensatory augmentation of atrial function. The study results can be used as reference data for the quantitative assessment of longitudinal LV and RV function in patients with cardiac disease.

Myocardial tissue velocity reduction is correlated with clinical neurologic severity in myotonic dystrophy

About 15% of patients with myotonic dystrophy (MD) die of ventricular arrhythmias, but few have documented left ventricular (LV) dysfunction and heart failure. This study prospectively evaluated a group of patients with MD without known heart failure to assess whether there is subclinical impairment of LV contractility using conventional 2-dimensional echocardiography and tissue Doppler imaging, and to correlate any abnormalities found with the degree of neurologic severity and cytosine-thymine-guanine trinucleotide repeat length. Twenty-two patients with MD without known heart failure were evaluated and compared with 22 healthy, age-matched controls. The patients with MD and control subjects did not differ with respect to LV ejection fraction (60 +/- 5% vs 60 +/- 4%, respectively, p = 0.86). However, peak systolic velocities were significantly lower in subjects with MD compared with controls in the basal lateral (6.1 +/- 2.6 vs 8.2 +/- 2.0 cm/s, p <0.005), basal septal (5.0 +/- 1.1 vs 6.3 +/- 1.1 cm/s, p <0.0003), and mitral annulus-lateral segments (7.6 +/- 1.9 vs 9.2 +/- 1.9 cm/s, p = 0.007). Mean LV velocities were also lower in subjects with MD (6.2 +/- 1.3 vs 7.5 +/- 1.1 cm/s, p <0.002). In subjects with MD, the peak systolic velocities correlated inversely with neurologic severity (r = -0.51, p = 0.014) but not with trinucleotide repeat length. In conclusion, patients with MD without known heart failure were found to have reduced myocardial tissue velocities; the degree of velocity reduction correlated with their neurologic severity.

Acute reductions in ventricular myocardial tissue velocities after direct current cardioversion of atrial fibrillation

BACKGROUND

Cardioversion by direct current (DC) and other methods can cause atrial "stunning." There are case reports of acute pulmonary edema after DC cardioversion, but whether acute ventricular dysfunction is a general consequence of DC cardioversion is unknown. We have investigated whether DC cardioversion acutely affects myocardial velocity assessed by Doppler tissue imaging.

METHODS

40 patients (30 with atrial fibrillation and 10 with atrial flutter) undergoing elective DC cardioversion underwent transthoracic echocardiography with Doppler tissue imaging before and immediately after cardioversion, and after follow-up. Peak systolic velocity was derived for 6 ventricular segments using Doppler tissue imaging.

RESULTS

Immediately after DC cardioversion of atrial fibrillation, peak systolic velocity decreased in basal lateral (4.3 +/- 2.0-3.3 +/- 1.7 cm/s, P <.001), mitral annulus-septal (3.8 +/- 1.0-3.5 +/- 0.9, P <.05), mitral annulus-lateral (4.9 +/- 1.6-4.1 +/- 1.7, P <.001), and tricuspid annular (7.8 +/- 2.0-7.0 +/- 1.2, P <.03) segments, even though left ventricular ejection fraction was unchanged. In contrast, for the atrial flutter group there were no significant changes in peak systolic velocity in any segment post-DC cardioversion. Follow up studies were performed after sustained in sinus rhythm in both atrial fibrillation and atrial flutter groups. For both groups, increased peak systolic velocity was found in all 6 segments on follow-up (all P <.05).

CONCLUSIONS

DC cardioversion causes subclinical, acute reversible reduction in left ventricular peak systolic velocity in patients with atrial fibrillation. The causes of this reduction in myocardial contractile velocity and the circumstances in which acute dysfunction become clinically significant warrant further investigation.

Specific tissue Doppler predictors of preserved systolic and diastolic left ventricular function after an acute anterior myocardial infarction

The degree of left ventricular (LV) dysfunction determines the outcome of patients suffering an acute anterior myocardial infarction (AAMI). Many recent studies have utilized tissue Doppler echocardiography (TDE) parameters in the assessment of LV function. We sought to investigate whether some variables easily obtained from TDE profiles of mitral annulus corners would predict a relatively preserved LV global function traditionally assessed with ejection fraction (EF) and deceleration time (DT), within the acute phase of AAMI. Included were 50 consecutive patients with a first AAMI. Standard echocardiography and TDE of mitral annulus were performed within 36 hours of admission. Pulsed wave sample volumes were set at the septal, lateral, anterior, and inferior corners of the mitral annulus. Preserved LV function was defined as an EF > 40% together with a DT > or = 140 ms and < 220 ms. An inferior annular systolic velocity of > 7.5 cm/s predicts preserved global left ventricular function with a sensitivity of 81% and specificity of 71%. An anterior mitral annular early diastolic velocity of > 8cm/s had a sensitivity of 69% and specificity of 85%. When these two velocities both exceed the limits above, such a combined index yielded a sensitivity of 69%, specificity of 94%, and an overall diagnostic accuracy of 86% for the estimation of preserved LV global function. The parameters derived from TDE profiles of inferior and anterior mitral annulus comers provide valuable information to predict preserved global left ventricular function during the early period of AAMI.

Relationship between noninvasive reperfusion criteria and pulsed-wave tissue Doppler parameters in patients with acute myocardial infarction receiving thrombolytic therapy

Several studies have proven that noninvasive reperfusion criteria (NRC) have prognostic significance in patients receiving thrombolytic therapy (TT) after acute myocardial infarction (acute MI). In this study, we investigated the relationship between NRC and pulsed tissue Doppler (PTD) parameters in patients receiving TT after acute MI, and the role of PTD in the management and follow-up of patients with acute MI. The study group(n= 41)was divided into four subgroups defined as: anterior and posterior MI, with or without NRC. In the first PTD measurements (2-3 days after acute MI), all acute MI patients had significantly smaller peak systolic (S-wave) velocity in all evaluated segments and longer Q-Speak durations (time elapsed from the inscription of the Q-wave on the surface ECG to the peak of the S-wave in PTD) as compared with control patients(n= 22; P < 0.001 for both). Among the diastolic parameters, the E/A ratio was significantly smaller in the study group compared with the control group(P < 0.001). Among the patients who had received TT in the first 2 hours, those patients who had NRC displayed significantly higher peak S-wave values in all evaluated segments than those without NRC(P < 0.05). The second PTD study (4-5 weeks after acute MI), revealed that the difference between the systolic PTD parameters of the noninfarcted regions of the study and control groups disappeared. Infarct-related segments, however, displayed significant improvement only in patients having NRC. There was a significant positive correlation between the mean mitral annular S-wave velocity and left ventricular ejection fraction(r = 0.59, P < 0.001). In conclusion, a significant relationship was observed between the PTD parameters and the NRC, which are known to have prognostic significance.

Diastolic response during dobutamine stress echocardiography evaluated by a tissue velocity imaging technique is a sensitive indicator for diagnosing coronary artery disease

BACKGROUND

Tissue velocity imaging (TVI) is a new method that measures regional myocardial velocities on the basis of color Doppler myocardial imaging principles.

METHODS

To diagnose coronary artery disease (CAD) objectively by evaluating left ventricular diastolic responses during dobutamine stress echocardiography (DSE) with TVI, we performed DSE in 22 healthy participants and 28 patients with angina pectoris without wall-motion abnormality at rest. Before and during DSE, we measured the differences of time intervals from the R wave on electrocardiogram to the peak of early diastolic myocardial velocity in the same cardiac cycle between basal segments and midsegments in the septal (dT-S) and inferior (dT-I) walls by TVI.

RESULTS

During DSE, dT-S in patients with left anterior descending CAD and dT-I in patients with right CAD were prolonged compared with that in healthy participants (both P <.01). The localization of the segments with a dT-S or dT-I during low-dose (10 microg/kg/min) dobutamine infusion of >32 milliseconds allowed the correct identification of the stenosed vessel in 87% of 23 patients for whom DSE was performed with the TVI technique before coronary angiography.

CONCLUSIONS

The analysis of regional left ventricular diastolic responses to dobutamine stress using TVI was useful for the objective diagnosis of CAD.

Apical tissue tracking echocardiography for characterization of regional left ventricular function: comparison with magnetic resonance imaging in patients after myocardial infarction

OBJECTIVE

The purpose of this study was to characterize the normal pattern of apical tracking and to investigate whether tissue tracking imaging is more useful for evaluation of regional left-ventricular function than noncontrast harmonic echocardiography in patients after myocardial infarction.

BACKGROUND

Left ventricular longitudinal shortening plays an important role in cardiac contraction, and can be evaluated online by a new Doppler tissue imaging method.

METHODS

We included 40 healthy participants and 40 patients after myocardial infarction. They underwent tissue tracking imaging and noncontrast harmonic imaging by an experienced and an inexperienced observer. Diagnostic accuracy of semiquantitative evaluation of left ventricular function was compared using magnetic resonance imaging as reference method.

RESULTS

Velocity-time integrals decreased from basal to apical segments in healthy participants. Tissue tracking imaging has a higher diagnostic sensitivity than noncontrast imaging for the diagnosis of regional wall-motion abnormalities (expert, 78% vs 97%, P <.01; beginner, 63% vs 91%, P <.001), whereas specificity remained unchanged (expert, 99% vs 97%, not significant; beginner, 91% vs 92%, not significant).

CONCLUSIONS

Tissue tracking imaging is feasible and evaluates regional systolic myocardial function quantitatively with high diagnostic accuracy compared with magnetic resonance imaging in patients after myocardial infarction, and is more accurate than noncontrast harmonic echocardiography.

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.