Strain Rate Dobutamine Echocardiography for Prediction of Recovery After Revascularization in Patients With Ischemic Left Ventricular Dysfunction

Coordinate-Independent 3-D Ultrasound Principal Stretch and Direction Imaging

OBJECTIVE

In clinical ultrasound, current 2-D strain imaging faces challenges in quantifying three orthogonal normal strain components. This requires separate image acquisitions based on the pixel-dependent cardiac coordinate system, leading to additional computations and estimation discrepancies due to probe orientation. Most systems lack shear strain information, as displaying all components is challenging to interpret.

METHODS

This paper presents a 3-D high-spatial-resolution, coordinate-independent strain imaging approach based on principal stretch and axis estimation. All strain components are transformed into three principal stretches along three normal principal axes, enabling direct visualization of the primary deformation. We devised an efficient 3-D speckle tracking method with tilt filtering, incorporating randomized searching in a two-pass tracking framework and rotating the phase of the 3-D correlation function for robust filtering. The proposed speckle tracking approach significantly improves estimates of displacement gradients related to the axial displacement component. Non-axial displacement gradient estimates are enhanced using a correlation-weighted least-squares method constrained by tissue incompressibility.

RESULTS

Simulated and in vivo canine cardiac datasets were evaluated to estimate Lagrangian strains from end-diastole to end-systole. The proposed speckle tracking method improves displacement estimation by a factor of 4.3 to 10.5 over conventional 1-pass processing. Maximum principal axis/direction imaging enables better detection of local disease regions than conventional strain imaging.

CONCLUSION

Coordinate-independent tracking can identify myocardial abnormalities with high accuracy.

SIGNIFICANCE

This study offers enhanced accuracy and robustness in strain imaging compared to current methods.

Non-invasive Imaging in Patients With Chronic Total Occlusions of the Coronary Arteries-What Does the Interventionalist Need for Success?

Chronic total occlusion (CTO) of coronary arteries is a common finding in patients with known or suspected coronary artery disease (CAD). Although tremendous advances have been made in the interventional treatment of CTOs over the past decade, correct patient selection remains an important parameter for achieving optimal results. Non-invasive imaging can make a valuable contribution. Ischemia and viability, two major factors in this regard, can be displayed using echocardiography, single-photon emission tomography, positron emission tomography, computed tomography, and cardiac magnetic resonance imaging. Each has its own strengths and weaknesses. Although most have been studied in patients with CAD in general, there is an increasing number of studies with positive preselectional factors for patients with CTOs. The aim of this review is to provide a structured overview of the current state of pre-interventional imaging for CTOs.

Early Diagnosis of Cardiovascular Diseases in Workers: Role of Standard and Advanced Echocardiography

Cardiovascular disease (CVD) still remains the main cause of morbidity and mortality and consequently early diagnosis is of paramount importance. Working conditions can be regarded as an additional risk factor for CVD. Since different aspects of the job may affect vascular health differently, it is important to consider occupation from multiple perspectives to better assess occupational impacts on health. Standard echocardiography has several targets in the cardiac population, as the assessment of myocardial performance, valvular and/or congenital heart disease, and hemodynamics. Three-dimensional echocardiography gained attention recently as a viable clinical tool in assessing left ventricular (LV) and right ventricular (RV) function, volume, and shape. Two-dimensional (2DSTE) and, more recently, three-dimensional speckle tracking echocardiography (3DSTE) have also emerged as methods for detection of global and regional myocardial dysfunction in various cardiovascular diseases and applied to the diagnosis of subtle LV and RV dysfunction. Although these novel echocardiographic imaging modalities have advanced our understanding of LV and RV mechanics, overlapping patterns often show challenges that limit their clinical utility. This review will describe the current state of standard and advanced echocardiography in early detection (secondary prevention) of CVD and address future directions for this potentially important diagnostic strategy.

Prediction of left ventricular contractile recovery using tissue Doppler strain and strain rate measurements at rest in patients undergoing percutaneous coronary intervention

The aim of the study was to assess the ability of tissue Doppler (TD) deformation analysis at rest to predict left ventricular contractile recovery in patients undergoing percutaneous coronary intervention (PCI). This prospective cohort enrolled 67 patients with segmental wall motion abnormality. Assessment of each segment was performed at rest and during low dose Dobutamine stress echocardiography (DSE) using a 4 point scoring system, TD peak systolic strain (PSS) and peak systolic strain rate (PSSR). The study followed up the patients for contractile improvement after 6 months of successful PCI by echocardiography. Of a 319 dysfunctional segments, 155 (49%) showed contractile recovery and 164 (51%) did not. PSS and PSSR at rest were significantly higher in recovered segments compared to segments without recovery (PSS: -7.27 ± 0.8 Vs. -6.14 ± 0.7%, PSSR: -0.34 ± 0.13 Vs. -0.24 ± 0.1/s. p < 0.0001 both). Similarly, both parameters were significantly higher in the contractile recovery group at follow up (p 0.001). Resting PSSR as well as PSS and PSSR during DSE were significant independent predictors of contractile recovery (p < 0.001 each). For predicting segmental contractile recovery, resting PSSR with a -0.31/s cut-off point had 76% sensitivity and 59% specificity (AUC 0.74), DSE qualitative viability assessment had a sensitivity of 75% and specificity of 77%, DSE PSS with a cut-off point of -9.1% had 74% sensitivity and 63% specificity (AUC 0.77) and DSE PSSR with a cut-off point of -0.72/s had 78% sensitivity and 77% specificity (AUC 0.81). Resting PSSR is a modest predictor of segmental contractile recovery after PCI while PSSR during DSE has a comparable diagnostic performance to subjective wall motion scoring. Recovered segments show improvement of deformation parameters after PCI.

Current and evolving echocardiographic techniques for the quantitative evaluation of cardiac mechanics: ASE/EAE consensus statement on methodology and indications endorsed by the Japanese Society of Echocardiography

Echocardiographic imaging is ideally suited for the evaluation of cardiac mechanics because of its intrinsically dynamic nature. Because for decades, echocardiography has been the only imaging modality that allows dynamic imaging of the heart, it is only natural that new, increasingly automated techniques for sophisticated analysis of cardiac mechanics have been driven by researchers and manufacturers of ultrasound imaging equipment. Several such techniques have emerged over the past decades to address the issue of reader's experience and inter-measurement variability in interpretation. Some were widely embraced by echocardiographers around the world and became part of the clinical routine, whereas others remained limited to research and exploration of new clinical applications. Two such techniques have dominated the research arena of echocardiography: (1) Doppler-based tissue velocity measurements, frequently referred to as tissue Doppler or myocardial Doppler, and (2) speckle tracking on the basis of displacement measurements. Both types of measurements lend themselves to the derivation of multiple parameters of myocardial function. The goal of this document is to focus on the currently available techniques that allow quantitative assessment of myocardial function via image-based analysis of local myocardial dynamics, including Doppler tissue imaging and speckle-tracking echocardiography, as well as integrated back- scatter analysis. This document describes the current and potential clinical applications of these techniques and their strengths and weaknesses, briefly surveys a selection of the relevant published literature while highlighting normal and abnormal findings in the context of different cardiovascular pathologies, and summarizes the unresolved issues, future research priorities, and recommended indications for clinical use.

Current and evolving echocardiographic techniques for the quantitative evaluation of cardiac mechanics: ASE/EAE consensus statement on methodology and indications endorsed by the Japanese Society of Echocardiography

Echocardiographic imaging is ideally suited for the evaluation of cardiac mechanics because of its intrinsically dynamic nature. Because for decades, echocardiography has been the only imaging modality that allows dynamic imaging of the heart, it is only natural that new, increasingly automated techniques for sophisticated analysis of cardiac mechanics have been driven by researchers and manufacturers of ultrasound imaging equipment.Several such technique shave emerged over the past decades to address the issue of reader's experience and inter measurement variability in interpretation.Some were widely embraced by echocardiographers around the world and became part of the clinical routine,whereas others remained limited to research and exploration of new clinical applications.Two such techniques have dominated the research arena of echocardiography: (1) Doppler based tissue velocity measurements,frequently referred to as tissue Doppler or myocardial Doppler, and (2) speckle tracking on the basis of displacement measurements.Both types of measurements lend themselves to the derivation of multiple parameters of myocardial function. The goal of this document is to focus on the currently available techniques that allow quantitative assessment of myocardial function via image-based analysis of local myocardial dynamics, including Doppler tissue imaging and speckle-tracking echocardiography, as well as integrated backscatter analysis. This document describes the current and potential clinical applications of these techniques and their strengths and weaknesses,briefly surveys a selection of the relevant published literature while highlighting normal and abnormal findings in the context of different cardiovascular pathologies, and summarizes the unresolved issues, future research priorities, and recommended indications for clinical use.

Personalized echocardiography: clinical applications of advanced echocardiography and future directions

Future cardiology practice will be increasingly individualized, and thus to maintain its central role, echocardiography must keep pushing to expand the boundaries of real-time data acquisition from tissue and fluid motion, and yet still provide efficient and timely data analysis that leads to succinct, clear clinical recommendations tailored to each person in our care. In this article, recent efforts to expand echocardiography techniques into an era of increasingly personalized cardiology, including advances in color-coded tissue Doppler, 3D echocardiography and complex exercise stress echocardiography are described. The common metric for success in each of these efforts is the development of robust and institutionally supportable echocardiography protocols for specific cardiology disease populations that currently may be underdiagnosed and/or undertreated. The common result in each case should be the creation of new guidelines that can supplement the current standard protocols advocated by professional echocardiography organizations.

Is detection of hibernating myocardium necessary in deciding revascularization in systolic heart failure?

Although the prognosis of systolic heart failure, also called heart failure with reduced ejection fraction, has improved with advances in therapy, the prognosis remains poor in patients who become refractory to such therapies. That cardiac transplantation improves the quality of life and survival of such patients has been established, but it is available to a very small number of patients. Thus, newer pharmacologic and nonpharmacologic therapies for patients with refractory systolic heart failure are being explored. Because chronic ischemic heart disease is the most common cause of systolic heart failure, potential exists for revascularization therapy. Although revascularization can be performed with low procedural mortality, improvement in left ventricular function, relief of symptoms, and long-term prognosis appear to be related to the presence and extent of viable ischemic hibernating myocardium. In conclusion, the detection of hibernating myocardium is highly desirable before revascularization treatment is undertaken.

The Myoblast Autologous Grafting in Ischemic Cardiomyopathy (MAGIC) Trial

Background— Phase I clinical studies have demonstrated the feasibility of implanting autologous skeletal myoblasts in postinfarction scars. However, they have failed to determine whether this procedure was functionally effective and arrhythmogenic.

Methods and Results— This multicenter, randomized, placebo-controlled, double-blind study included patients with left ventricular (LV) dysfunction (ejection fraction ≤35%), myocardial infarction, and indication for coronary surgery. Each patient received either cells grown from a skeletal muscle biopsy or a placebo solution injected in and around the scar. All patients received an implantable cardioverter-defibrillator. The primary efficacy end points were the 6-month changes in global and regional LV function assessed by echocardiography. The safety end points comprised a composite index of major cardiac adverse events and ventricular arrhythmias. Ninety-seven patients received myoblasts (400 or 800 million; n=33 and n=34, respectively) or the placebo (n=30). Myoblast transfer did not improve regional or global LV function beyond that seen in control patients. The absolute change in ejection fraction (median [interquartile range]) between 6 months and baseline was 4.4% (0.2; 7.3), 3.4% (−0.3; 12.4), and 5.2% (−4.4; 11.0) in the placebo, low-dose, and high-dose groups, respectively ( P =0.95). However, the high-dose cell group demonstrated a significant decrease in LV volumes compared with the placebo group. Despite a higher number of arrhythmic events in the myoblast-treated patients, the 6-month rates of major cardiac adverse events and of ventricular arrhythmias did not differ significantly between the pooled treatment and placebo groups.

Conclusions— Myoblast injections combined with coronary surgery in patients with depressed LV function failed to improve echocardiographic heart function. The increased number of early postoperative arrhythmic events after myoblast transplantation, as well as the capability of high-dose injections to revert LV remodeling, warrants further investigation.

Assessment of left ventricular function by cardiac ultrasound

Our understanding of the physical underpinnings of the assessment of cardiac function is becoming increasingly sophisticated. Recent developments in cardiac ultrasound permit exploitation of many of these newer physical concepts with current echocardiographic machines. This review will first focus on the current approach to the assessment of cardiovascular hemodynamics by cardiac ultrasound. The next focus will be the assessment of global cardiac mechanics in systole and diastole. Finally, relationships between the cardiac structure and regional myocardial function, and the way regional function can be quantified by ultrasound, will be presented. This review also discusses the clinical impact of echocardiography and its future directions and developments.