Tissue Doppler imaging a new prognosticator for cardiovascular diseases

Tissue Doppler imaging (TDI) is evolving as a useful echocardiographic tool for quantitative assessment of left ventricular (LV) systolic and diastolic function. Recent studies have explored the prognostic role of TDI-derived parameters in major cardiac diseases, such as heart failure, acute myocardial infarction, and hypertension. In these conditions, myocardial mitral annular or basal segmental (Sm) systolic and early diastolic (Ea or Em) velocities have been shown to predict mortality or cardiovascular events. In particular, those with reduced Sm or Em values of <3 cm/s have a very poor prognosis. In heart failure and after myocardial infarction, noninvasive assessment of LV diastolic pressure by transmitral to mitral annular early diastolic velocity ratio (E/Ea or E/Em) is a strong prognosticator, especially when E/Ea is > or =15. In addition, systolic intraventricular dyssynchrony measured by segmental analysis of myocardial velocities is another independent predictor of adverse clinical outcome in heart failure subjects, even when the QRS duration is normal. In heart failure patients who received cardiac resynchronization therapy, the presence of systolic dyssynchrony at baseline is associated with favorable LV remodeling, which in turn predicts a favorable long-term clinical outcome. Finally, TDI and derived deformation parameters improve prognostic assessment during dobutamine stress echocardiography. A high mean Sm value in the basal segments of patients with suspected coronary artery disease is associated with lower mortality rate or myocardial infarction and is superior to the wall motion score.     

Tissue Doppler imaging: clinical topics for the new millenium.

INTRODUCTION: Tissue Doppler imaging is an echocardiographic technique that allows the selective visualization and quantification of myocardial signals. Its aim is to complement the conventional Doppler study, adding more and better information on specific topics of cardiovascular diseases. During the first seven years of the technique, much scientific work was produced and some clinical applications of the method have emerged. CLINICAL APPLICATIONS: I--non ischemic heart disease: The technique has been widely used in diastology, in hypertrophic cardiomyopathy, in heart transplant patients and in arrhythmology. II--ischemic heart disease: The quantitative assessment of regional diastolic and systolic function makes the technique very promising during stress echocardiography and during percutaneous transluminal coronary angioplasty. CONCLUSIONS: In 2000, tissue Doppler echocardiography is still a young, exciting and promising technique. Despite the fact that much has already been done, there is still a long way to go, implying a great amount of time and personal investment. How often do we feel that we are building a small part of the future?     

Tissue Doppler imaging for predicting outcome in patients with cardiovascular disease

PURPOSE OF REVIEW: Tissue Doppler imaging is being increasingly used for assessing global ventricular function in systole and diastole, and for quantifying regional wall motion abnormalities both in systolic heart failure with mechanical dyssynchrony and ischemic heart disease. Its use as a predictive tool is recent and the authors review publications relating to this aspect. RECENT FINDINGS: Peak early diastolic mitral annular velocity is a powerful predictor of outcome in a variety of cardiovascular conditions and adds incremental value to clinical parameters and standard mitral Doppler inflow velocities. Tissue Doppler imaging can also predict the development of hypertrophic cardiomyopathy in asymptomatic individuals carrying the genetic mutation even before the onset of overt left ventricular hypertrophy. In addition, the standard deviation of the time to peak systolic velocity is a good marker of mechanical asynchrony and can predict reverse remodeling. It may also be useful in identifying individuals with ischemic heart disease and regional wall motion abnormalities who have an adverse outcome. SUMMARY: Tissue Doppler imaging is a powerful new echocardiographic tool that is now becoming the standard for assessing ventricular function in a variety of situations and diseases.     

Tissue Doppler imaging in coronary artery diseases and heart failure

Recent studies have explored the prognostic role of TDI-derived parameters in major cardiac diseases, such as coronary artery disease (CAD) and heart failure (HF). In these conditions, myocardial mitral annular systolic (S') and early diastolic (E') velocities have been shown to predict mortality or cardiovascular events. In heart failure non invasive assessment of LV diastolic pressure by transmitral to mitral annular early diastolic velocity ratio (E/E') is a strong prognosticator, especially when E/E' is > or =15. Moreover, other parameters derived by TDI, as cardiac time intervals and Myocardial Performance Index, might play a role in the prognostic stratification in CAD and HF. Recently, a threedimensional (3-D) TDI imaging modality, triplane TDI, has become available, and this allows calculation of 3-Dvolumes and LV ejection fraction. We present a brief update of TDI.     

Tissue Doppler and strain imaging: a new tool for early detection of cardiac amyloidosis

Using traditional echocardiography, the diagnosis of cardiac amyloidosis (CA) is often only possible in advanced stage when recommended therapies may have adverse effects. The aim of our study was to evaluate whether additional information can be derived from Tissue and strain Doppler imaging (TDI and SDI). Forty patients with systemic amyloidosis and 24 healthy subjects underwent traditional, tissue and strain Doppler echocardiography. Patients were classified having CA if mean wall thickness (mT), was half of the sum septum and posterior wall thickness, was ≥12 mm. The following parameters were evaluated: peak early diastolic velocity (Em) as index of ventricular relaxation, mitral E-wave to Em ratio (E/Em) as index of left ventricular (LV) filling pressure and mean LV strain peak curves (mSt) as global long-axis contraction index. In non cardiac amyloidosis (NCA), both Em and mSt were lower than in age matched controls (p < 0.01, p < 0.05, respectively) and higher than in CA (p < 0.01 and p < 0.01, respectively). Both Em and mSt were related to mT (p < 0.001). A significant (p < 0.01) nonlinear relation was observed between plasma terminal of pro B-natriuretic peptide and mT, Em, E/Em and mSt. TDI and SDI are able to detect amyloid myocardial involvement in such an early stage that cannot be evidenced by using traditional echocardiography.     

Tissue Doppler imaging for the pre-clinical diagnosis of cardiomyopathy.

This editorial refers to "Tissue Doppler imaging detects early asymptomaticmyocardial abnormalities in a dog model of Duchenne's cardiomyopathy"by V. Chetboul on page 1934 Duchenne muscular dystrophy is an important cause of cardiomyopathyin children and adolescents and is caused by mutations in thegene coding for the protein dystrophin [1]. Dystrophin participatesin linking the sarcomere to the sarcolemma and extracellularmatrix and plays a role in cell signalling [2]. The diseaseis characterised by skeletal and cardiac myopathies. Becauseit is inherited as an X-linked recessive disorder,     

Tissue Doppler imaging and strain Doppler imaging as modalities for predicting clinical improvement in patients receiving biventricular pacing.

BACKGROUND: The purpose of this study was to determine the utility and efficacy of tissue Doppler imaging (TDI) and strain Doppler imaging (SDI) for evaluating ventricular synchrony and function, and for predicting the long-term clinical improvement in patients undergoing biventricular pacing (BVP). METHODS AND RESULTS: TDI and SDI were performed before and <1 month after initiating BVP in 17 patients with advanced heart failure. An intraventricular conduction delay between the left ventricular (LV) septal and lateral walls was measured by TDI. The average LV strain (LV-strain) was calculated from data obtained at the center of 6 regions of the LV (base and mid-point between the basal and apical portions, and the mid-point between these 2 points on the septal and lateral walls). During a 23+/-7 month follow-up period, 12 patients improved clinically and did not require re-hospitalization for heart failure (responder group), but the remaining 5 did not improve (nonresponder group). Before BVP, the intraventricular conduction delay was greater in the responder group than in the nonresponder group (p<0.01), but after BVP, it did not differ between the 2 groups. LV-strain improved after BVP in the responder group but not in the nonresponder group (p<0.05). CONCLUSION: A high intraventricular conduction delay before BVP and decreased strain shortly after BVP may predict long-term clinical improvement in patients undergoing this treatment.     

Tissue Doppler imaging in Fabry disease

PURPOSE OF REVIEW: The development of effective enzyme replacement/enhancement therapy makes of clinical relevance considering Fabry disease in the differential diagnosis of patients with hypertrophic cardiomyopathy. In particular the opportunity to significantly modify the clinical progression of the disease has reinforced the need for early diagnosis of Fabry cardiomyopathy. RECENT FINDINGS: The study with tissue Doppler of Fabry patients with endomyocardial biopsy-proven cardiac involvement showed a reduction of both diastolic and systolic myocardial velocities recorded at septal and lateral corners of mitral annulus. Tissue Doppler abnormalities were present not only in patients with left ventricular hypertrophy but also in younger patients with normal cardiac wall thickness and represent the first sign of myocardial damage. Furthermore tissue Doppler studies have been shown useful in detecting cardiac involvement in female carriers with no systemic manifestations of Fabry disease. In patients already submitted to enzyme-replacement therapy tissue Doppler and strain rate imaging represent useful noninvasive tools in assessing treatment efficacy. SUMMARY: Tissue Doppler imaging can provide early detection of cardiac involvement in Fabry disease and represents the most accurate and sensitive noninvasive tool for the diagnosis of myocardial dysfunction and for the assessment of cardiac improvement during enzyme replacement therapy. The detection of tissue Doppler abnormalities in female carriers may represent a hint for an invasive assessment of cardiac involvement.     

Overview of stem cells and imaging modalities for cardiovascular diseases.

Stem cell therapy is emerging as a promising approach to treat heart diseases. Considerable evidence from experimental studies and initial clinical trials suggests that stem cell transplantation promotes systolic function and prevent ventricular remodeling. However, the specific mechanisms by which stem cells improve heart function remain largely unknown. In addition, interpreting the long-term effects of stem cell therapy is difficult because of the limitations of conventional techniques. The recent development of molecular imaging techniques offers great potential to address these critical issues by noninvasively tracking the fate of the transplanted cells. This review offers a focused discussion on the use of stem cell therapy and imaging in the context of cardiology.     

Tissue Doppler imaging in the normal fetus

Tissue Doppler imaging is a new non-invasive method that derives measurements of relaxation velocities directly from the myocardium. This approach to studying myocardial velocities offers the potential for quantitative assessment of diastolic ventricular function. Data on myocardial tissue velocities in normal fetuses have not been established. We measured motion velocities of the left ventricular posterior wall, right ventricular anterior wall, interventricular septum along the long axis in 30 normal fetuses aged 19-38 weeks gestation (mean, 26.3+/-6.0 weeks). In all fetuses, peak myocardial velocities during early diastole (EW) and atrial contraction (AW) waves were recorded. The mean values for EW, AW, and E/AW of left ventricle were 5.4+/-1.7, 7.0+/-1.4 cm/s, and 0.77+/-0.19, respectively, and those of right ventricle were 5.5+/-1.5, 7.8+/-1.5 cm/s, and 0.70+/-0.14, respectively. The EW(4.1+/-1.0 cm/s) and the AW (5.3+/-0.8 cm/s) of the interventricular septum were significantly lower than those of the left and right ventricular walls (P<0.01). The EW and E/AW of the left ventricular wall increased significantly with increasing gestational age (r=0.81 and 0.85, respectively, P<0.01). Similar changes were observed in the myocardial velocities of the right ventricular wall. The EW and E/AW of the interventricular septum also increased significantly with age (r=0.63 and 0.78, respectively, P<0.01). However, AW of the interventricular septum showed little changes. In both ventricles, there were significant correlations between tissue Doppler E/AW and pulsed Doppler E/A (LV, r=0.56; and RV, r=0.60, P<0.01). Assessment of myocardial tissue velocities in fetuses is feasible with tissue Doppler imaging. Age-related alterations in tissue Doppler velocities may suggest age-related maturational changes in diastolic function.     

Tissue Doppler imaging for the diagnosis of coronary artery disease

PURPOSE OF REVIEW: Tissue Doppler imaging (TDI) is a diagnostic method that provides quantitative data about myocardial function. The present review discusses the most recent developments in the application of TDI in coronary artery disease. RECENT FINDINGS: The most widely used TDI modality is velocity imaging, and systolic function is measured as peak velocity during LV ejection. Several recent studies show that TDI measurements during the LV isovolumic phases provide unique information regarding myocardial dysfunction. Since velocity imaging is confounded by influence from velocities in other segments, the TDI-based modalities strain- and strain rate imaging (SRI) have been introduced to measure regional shortening fraction and shortening rate, respectively.Velocity imaging during stress echocardiography has been validated clinically and appears equivalent, but not superior to conventional visual assessment of grey scale images. Potentially, more comprehensive evaluation that includes the use of SRI may improve the diagnostic power of TDI further. Preliminary reports suggest that TDI may have an important role in the assessment of viability in acute coronary occlusion, but this needs to be demonstrated in appropriately designed clinical trials. SUMMARY: At the present time tissue Doppler velocity imaging can be recommended for clinical use, especially the pulsed mode. Strain rate imaging may be useful as additional imaging, but needs further refinement before it is ready for routine clinical use.     

Endothelial progenitor cells: a new target for the prevention of cardiovascular diseases.

Endothelial progenitor cells (EPCs) are circulating precursor cells that have been implicated recently in vascular and cardiac regeneration. There is an ongoing discussion on the immunocytological definition of EPCs, based on various surface markers, and currently different cell types are included in the term 'EPC'. This review summarizes the mechanisms that influence function, survival, mobilization and differentiation of EPCs. Furthermore, there are several reports on the clinical use of EPCs for the treatment of cardiovascular diseases. We have focused specifically on the influence of physical activity on EPC function.     

Tissue Doppler imaging for the evaluation of patients with hypertrophic cardiomyopathy

PURPOSE OF REVIEW: To discuss the role of tissue Doppler imaging for assessing regional myocardial function in patients with proven or suspected hypertrophic cardiomyopathy and review its application in clinical practice for diagnosis, estimation of filling pressures, and monitoring of treatment. RECENT FINDINGS: Patients with hypertrophic cardiomyopathy have very abnormal systolic and diastolic myocardial function, even if global systolic function of the left ventricle appears normal. Regional function is most abnormal in walls that are markedly hypertrophied, but it is also abnormal in segments that are not affected by hypertrophy, and it is depressed in patients who have a mutation for hypertrophic cardiomyopathy but have not yet developed clear phenotypic changes. Genetic diagnosis remains difficult especially in sporadic cases, due to the very large number of mutations that have been identified; the hypertrophy may represent a nonspecific compensatory response to any mutation that impairs myofibrillar function. Subclinical changes especially affect long-axis ventricular function, and tissue Doppler imaging is the most sensitive test to identify reduced velocities of long-axis shortening and early diastolic lengthening of the left ventricle, prolonged contraction and relaxation times, and reduced strain in affected segments, both in patients with hypertrophy and in asymptomatic subjects with mutations. It can also discriminate well between hypertrophic cardiomyopathy and athlete's heart, and can be used with standard echocardiographic measurements to estimate left ventricular filling pressure or to monitor treatment. SUMMARY: Tissue Doppler imaging can now be usefully incorporated into the routine echocardiographic study of patients with proven or suspected hypertrophic cardiomyopathy.     

Tissue Doppler imaging to assess left ventricular dyssynchrony and resynchronization therapy.

We describe the use of tissue Doppler imaging to assess left ventricular dyssynchrony and subsequent resynchronization in a patient with end-stage heart failure undergoing cardiac resynchronization therapy.     

Tissue Doppler imaging and the quantification of myocardial function

Tissue Doppler imaging (TDI) has recently been introduced in clinical echocardiography. Most widely used are tissue velocity maps, in which the velocity of moving tissue is calculated relative to the transducer from the Doppler shift and displayed as colour-encoded velocity maps in either M-mode or two-dimensional image formats (Doppler velocity mode). This allows detection and quantification of dyssynergic areas of the myocardium. Additionally, the velocities may be studied with pulsed wave-tissue Doppler sampling (PW-TDS) which displays the velocity of a selected myocardial region versus time with high temporal resolution. Less often used, are tissue acceleration maps which display acceleration or velocity change of subsequent frames as different colours (Doppler acceleration mode). These maps may find application in clinical electrophysiology. Another TDI modality is tissue energy imaging, which is based on the integration of the power spectrum of the Doppler signals from the tissue. This technique provides maps of Doppler energy which are represented as colour brightness. Such maps offer potential for the study of myocardial perfusion. TDI modalities have promise to become clinically useful for quantifying myocardial function.     

Tissue Doppler imaging detects early asymptomatic myocardial abnormalities in a dog model of Duchenne's cardiomyopathy.

AIMS: Early diagnosis of Duchenne's dilated cardiomyopathy remains a challenge for conventional echocardiography. We sought to determine whether tissue Doppler imaging (TDI) could detect early alteration in myocardial function in a dog model of Duchenne muscular dystrophy, i.e. the Golden Retriever Muscular Dystrophy (GRMD). METHODS AND RESULTS: Myocardial function was assessed by TDI in 20 dogs with normal conventional parameters of systolic function (eight controls and 12 GRMD, 25+/-11 weeks) without knowledge of the genotype. M-mode TDI was recorded from a short-axis view for measurement of endocardial and epicardial velocities and myocardial velocity gradient (MVG) within the posterior wall. Controls and GRMD dogs were comparable regarding left ventricular fractional shortening (37+/-2 vs 42+/-3%, p=ns). Conversely, TDI showed, in all GRMD dogs, a dramatic decrease in systolic MVG (0.8+/-0.1 vs 2.9+/-0.3 s(-1), p<0.0001) and early diastolic MVG (2.3+/-2.2 vs 10.8+/-1.1 s(-1), p<0.0001). This MVG alteration was related to a significant decrease in endocardial velocities in GRMD whereas epicardial velocities were comparable in the two groups. CONCLUSION: These results show that TDI is more sensitive than conventional echocardiography in detecting pre-clinical myocardial abnormalities before occurrence of left ventricular dilation and dysfunction. TDI should be part of the screening techniques for the early diagnosis of cardiomyopathy.