Detection of myocardial fibrosis by speckle-tracking echocardiography: from prediction to clinical applications

New perspectives in the echocardiographic hemodynamics multiparametric assessment of patients with heart failure

International Guidelines consider left ventricular ejection fraction (LVEF) as an important parameter to categorize patients with heart failure (HF) and to define recommended treatments in clinical practice. However, LVEF has some technical and clinical limitations, being derived from geometric assumptions and is unable to evaluate intrinsic myocardial function and LV filling pressure (LVFP). Moreover, it has been shown to fail to predict clinical outcome in patients with end-stage HF. The analysis of LV antegrade flow derived from pulsed-wave Doppler (stroke volume index, stroke distance, cardiac output, and cardiac index) and non-invasive evaluation of LVFP have demonstrated some advantages and prognostic implications in HF patients. Speckle tracking echocardiography (STE) is able to unmask intrinsic myocardial systolic dysfunction in HF patients, particularly in those with LV preserved EF, hence allowing analysis of LV, right ventricular and left atrial (LA) intrinsic myocardial function (global peak atrial LS, (PALS)). Global PALS has been proven a reliable index of LVFP which could fill the gaps "gray zone" in the previous Guidelines algorithm for the assessment of LV diastolic dysfunction and LVFP, being added to the latest European Association of Cardiovascular Imaging Consensus document for the use of multimodality imaging in evaluating HFpEF. The aim of this review is to highlight the importance of the hemodynamics multiparametric approach of assessing myocardial function (from LVFP to stroke volume) in patients with HF, thus overcoming the limitations of LVEF.

Quantifying fetal heart health in gestational diabetes: a new approach with fetal heart quantification technology

Objective

This study aimed to assess the impact of gestational diabetes mellitus (GDM) on fetal heart structure and function using a technique called fetal heart quantification (Fetal HQ), with a focus on mitochondrial dynamics, which employs advanced imaging technology for comprehensive analysis.

Methods

A total of 180 fetuses with normal heart structures, aged 24-40 weeks of gestation, were examined. A 2-3 s cine loop in the standard four-chamber oblique view was captured and analyzed using the speckle-tracking technique with Fetal HQ. Various echocardiographic parameters were evaluated, including four-chamber view (4CV), global spherical index (GSI), global longitudinal strain (GLS), 24-segment spherical index (SI), ventricular fractional area change (FAC), cardiac output (CO), and stroke volume (SV). These parameters were compared between the GDM group and the control group during two gestational periods: 24+0 to 28+0 weeks and 28+1 to 40+1 weeks. Statistical analysis was performed using independent samples t-tests and Mann-Whitney U tests to identify significant differences.

Results

Twenty fetuses from mothers with GDM and 40 from the control group were recruited at 24+0 to 28+0 weeks. At 28+1 to 40+1 weeks, 40 fetuses from mothers with GDM and 80 from the control group were recruited. The fetal left ventricular global longitudinal function was similar between the GDM and control groups. However, compared to the controls, right ventricular function in the GDM group was lower only at 28+1 to 40+1 weeks. In the GDM group, the global spherical index (GSI) was lower than in the control group at 28+1 to 40+1 weeks (1.175 vs. 1.22; p = 0.001). There were significant decreases in ventricular FAC (38.74% vs. 42.83%; p < 0.0001) and 4CV GLS for the right ventricle (-22.27% vs. -26.31%; p = 0.005) at 28+1 to 40+1 weeks.

Conclusion

Our findings suggest that GDM is associated with decreased right ventricular function in the fetal heart, particularly during the later stages of pregnancy (28+1 to 40+1 weeks), compared to fetuses from healthy pregnancies. The Fetal HQ technique represents a valuable tool for evaluating the structure and function of fetal hearts affected by GDM during the advanced stages of pregnancy.

Cardiovascular Structural and Functional Parameters in Idiopathic Pulmonary Fibrosis at Disease Diagnosis

INTRODUCTION

Prevalence of cardiac and vascular fibrosis in patients with Idiopathic Pulmonary Fibrosis (IPF) has not been extensively evaluated.

AIM

In this study, we aimed to evaluate the heart and vessels functional and structural properties in patients with IPF compared to healthy controls. An exploratory analysis regarding disease severity in IPF patients has been done.

METHODS

We enrolled 50 patients with IPF (at disease diagnosis before antifibrotic therapy initiation) and 50 controls matched for age and gender. Heart was evaluated through echocardiography and plasmatic NT-pro-brain natriuretic peptide that, together with patients' symptoms, allow to define the presence of Heart Failure (HF) and diastolic dysfunction. Vessels were evaluated through Flow Mediated Dilation (FMD - endothelial function) and Pulse Wave Velocity (PWV-arterial stiffness) RESULTS: Patients with IPF had a prevalence of diastolic disfunction of 83.8%, HF of 37.8% and vascular fibrosis of 76.6%. No statistically significant difference was observed in comparison to the control group who showed prevalence of diastolic disfunction, HF and vascular fibrosis of 67.3%, 24.5% and 84.8%, respectively. Disease severity seems not to affect PWV, FMD, diastolic dysfunction and HF.

CONCLUSIONS

Patients with IPF early in the disease course do not present a significant CV fibrotic involvement when compared with age- and sex-matched controls. Bigger and adequately powered studies are needed to confirm our preliminary data and longitudinal studies are required in order to understand the time of appearance and progression rate of heart and vascular involvement in IPF subjects.

Imaging of Cardiac Fibrosis: How Far Have We Moved From Extracellular to Cellular?

Cardiovascular disease is the leading cause of morbidity and mortality worldwide. Myocardial fibrosis plays an important role in adverse outcomes such as heart failure and arrhythmias. As the pathological response and degree of scarring, and therefore clinical presentation varies from patient to patient, early detection of fibrosis is crucial for identifying the appropriate treatment approach and forecasting the progression of a disease along with the likelihood of disease-related mortality. Current imaging modalities provides information about either decreased function or extracellular signs of fibrosis. Targeting activated fibroblasts represents a burgeoning approach that could offer insights prior to observable functional alterations, presenting a promising focus for potential anti-fibrotic therapeutic interventions at cellular level. In this article, we provide an overview of imaging cardiac fibrosis and discuss the role of different advanced imaging modalities with the focus on novel non-invasive imaging of activated fibroblasts.

Arrhythmic mitral valve prolapse: a practical approach for asymptomatic patients

Mitral valve prolapse (MVP) is usually regarded as a benign condition though the proportion of patients with a life-threatening arrhythmic MVP form remains undefined. Recently, an experts' consensus statement on arrhythmic MVP has proposed approaches for risk stratification across the spectrum of clinical manifestation. However, sudden cardiac death may be the first presentation, making clinicians focused to early unmasking this subset of asymptomatic patients. Growing evidence on the role of cardiac imaging in the in-deep stratification pathway has emerged in the last decade. Pathology findings have suggested the fibrosis of papillary muscles and inferobasal left ventricular wall as the malignant hallmark. Cardiac magnetic resonance, while of limited availability, allows the identification of this arrhythmogenic substrate. Therefore, speckle-tracking echocardiography may be a gateway to prompt referring patients to further advanced imaging investigation. Our review aims to summarize the phenotypic features linked to the arrhythmic risk and to propose an image-based algorithm intended to help stratifying asymptomatic MVP patients.

Left ventricular ejection fraction: clinical, pathophysiological, and technical limitations

Risk stratification of cardiovascular death and treatment strategies in patients with heart failure (HF), the optimal timing for valve replacement, and the selection of patients for implantable cardioverter defibrillators are based on an echocardiographic calculation of left ventricular ejection fraction (LVEF) in most guidelines. As a marker of systolic function, LVEF has important limitations being affected by loading conditions and cavity geometry, as well as image quality, thus impacting inter- and intra-observer measurement variability. LVEF is a product of shortening of the three components of myocardial fibres: longitudinal, circumferential, and oblique. It is therefore a marker of global ejection performance based on cavity volume changes, rather than directly reflecting myocardial contractile function, hence may be normal even when myofibril's systolic function is impaired. Sub-endocardial longitudinal fibers are the most sensitive layers to ischemia, so when dysfunctional, the circumferential fibers may compensate for it and maintain the overall LVEF. Likewise, in patients with HF, LVEF is used to stratify subgroups, an approach that has prognostic implications but without a direct relationship. HF is a dynamic disease that may worsen or improve over time according to the underlying pathology. Such dynamicity impacts LVEF and its use to guide treatment. The same applies to changes in LVEF following interventional procedures. In this review, we analyze the clinical, pathophysiological, and technical limitations of LVEF across a wide range of cardiovascular pathologies.

Signal intensity coefficient as a detector of aortic stenosis-induced myocardial fibrosis and its correlation to the long term outcome

OBJECTIVE

Despite advanced aortic valve replacement techniques, aortic stenosis (AS)-induced irreversible myocardial fibrosis contributes to poorer outcomes. Therefore, in addition to early diagnosis of AS, detecting myocardial fibrosis is crucial for physicians to determine the timing of surgery. The Signal Intensity Coefficient (SIC) was used to detect subtle myocardial deformation. Hence, we aimed to investigate whether SIC correlated with myocardial dysfunction and fibrosis from both clinical and preclinical perspectives.

METHODS

We collected medical records and echocardiography images, including the SIC of patients who underwent surgical aortic valve replacement (AVR) for AS from 2010 to 2015. The endpoint of the study was mortality. Median follow-up period was 80 months.

RESULTS

Among 109 patients, 15 died due to cardiovascular causes. Although SIC decreased in all patients post-AVR, patients with an SIC ≥0.34 before surgeries presented with a higher probability of cardiovascular death. In contrast, changes in the left ventricular (LV) ejection fraction, LV mass index, and LV volume failed to predict outcomes. Similarly, SIC was obtained in mice undergoing aortic banding and debanding surgery for comparison with the degree of myocardial fibrosis. SIC was continuously elevated after aortic banding and declined gradually after debanding surgery in mice. Debanding surgery indicated the regression of aortic banding-induced myocardial fibrosis.

CONCLUSION

Pre-AVR SIC was associated with the risk of cardiovascular death and reflected the degree of myocardial fibrosis. Further investigations are required to study the clinical application of SIC in patients with AS.

Speckle tracking tissue motion mitral annulus displacement to assess early changes in the left ventricle and its association with lung function in patients with chronic obstructive pulmonary disease

OBJECTIVE

To evaluate the early changes in left ventricular (LV) in patients with chronic obstructive pulmonary disease (COPD) by measuring tissue motion mitral annulus displacement (TMAD) and three-dimensional (3D) parameters using speckle tracking imaging (STI), and to explore its correlation with lung function.

METHODS

Forty two COPD patients (GOLD I, GOLD II, GOLD III) and 30 healthy individuals (control group) were included. STI was used to assess the changes in LV structure and systolic function. Receiver operating characteristic (ROC) curves were drawn, and correlations among TMAD parameters, LV systolic function, structural, pulmonary artery systolic pressure (PASP), and lung function were analyzed.

RESULTS

Compared to the control group, COPD patients were able to undergo LV remodeling, with a decrease in the absolute value of global longitudinal strain (GLS) and TMAD, but no significant modification of LVEF. Correlation analysis showed that TMAD was positively related to the absolute value of GLS (r > 0.51, P < 0.01) and predicted forced expiratory volume in the first second (FEV1%) (r > 0.56, P < 0.01), and negatively to PASP (r < -0.52, P < 0.01). The LV posterior wall thickness (LVPWd), relative wall thickness (RWT), end-diastolic volume (LVEDV) and PASP negatively correlated with FEV1%.

CONCLUSION

The LV geometric changes and systolic function impairment in COPD patients were found to correlate with airflow restriction (FEV1%). TMAD aided in detection of early changes in LV systolic function in COPD patients. It negatively correlated with PASP and positively with FEV1%. Moreover, it was more convenient than GLS.

99mTc-HFAPi imaging identifies early myocardial fibrosis in the hypertensive heart

BACKGROUND

This study aimed to explore whether 99mTc-radiolabeled fibroblast activation protein inhibitor (99mTc-HFAPi) imaging can detect early myocardial fibrosis in the hypertensive heart.

METHODS

In the experimental model, spontaneously hypertensive rats (SHRs) and age-matched Wistar Kyoto rats (WKYs) were randomly divided into three groups (8, 16, and 28 weeks). The animals underwent 99mTc-HFAPi imaging and echocardiography. Autoradiography and histological analyses were performed in the left ventricle. The mRNA and protein expression level of the fibroblast activation protein (FAP) and collagen I were measured using quantitative PCR and western blot. In the clinical investigation, a total of 106 patients with essential hypertension and 20 gender-matched healthy controls underwent 99mTc-HFAPi imaging and echocardiography.

RESULTS

In-vivo and in-vitro autographic images demonstrated diffusely enhanced 99mTc-HFAPi uptake in the SHR heart starting at week 8, before irreversible collagen deposition. The mRNA and protein levels of FAP in SHRs began to increase from week 8, whereas changes in collagen I levels were not detected until week 28. In the clinical investigation, even in hypertensive patients with normal diastolic indicators, normal left ventricular geometry, and normal global longitudinal strain (GLS), the prevalence of increased 99mTc-HFAPi uptake reached 34, 41, and 20%, respectively, indicating that early fibrogenesis precedes structural and functional myocardial abnormalities.

CONCLUSION

In hypertension, 99mTc-HFAPi imaging can detect early fibrotic process before myocardial functional and structural changes.

Cardiac Fibrosis in heart failure: Focus on non-invasive diagnosis and emerging therapeutic strategies

Heart failure is a leading cause of mortality and hospitalization worldwide. Cardiac fibrosis, resulting from the excessive deposition of collagen fibers, is a common feature across the spectrum of conditions converging in heart failure. Eventually, either reparative or reactive in nature, in the long-term cardiac fibrosis contributes to heart failure development and progression and is associated with poor clinical outcomes. Despite this, specific cardiac antifibrotic therapies are lacking, making cardiac fibrosis an urgent unmet medical need. In this context, a better patient phenotyping is needed to characterize the heterogenous features of cardiac fibrosis to advance toward its personalized management. In this review, we will describe the different phenotypes associated with cardiac fibrosis in heart failure and we will focus on the potential usefulness of imaging techniques and circulating biomarkers for the non-invasive characterization and phenotyping of this condition and for tracking its clinical impact. We will also recapitulate the cardiac antifibrotic effects of existing heart failure and non-heart failure drugs and we will discuss potential strategies under preclinical development targeting the activation of cardiac fibroblasts at different levels, as well as targeting additional extracardiac processes.

Speckle-Tracking Echocardiography Predicts Adverse Left Ventricular Remodeling After Valve Replacement in Rheumatic Mitral Stenosis

Background

Rheumatic mitral stenosis(RMS) may leads to left ventricular remodeling (LVR), which can persist even after valve surgery. Identifying markers for early structure and function in patients with rheumatic heart disease who are at risk for adverse LVR after surgery can help determine the optimal timing of intervention. This study aimed to investigate whether preoperative parameters of global left ventricular long-axis strain (LVGLS) and mechanical discretization (MD) could predict postoperative adverse LVR.

Methods

A total of 109 adult patients with RMS and 50 healthy controls were enrolled in this study. Baseline clinical features, conventional echocardiography results, LVGLS, and MD were compared between the two groups. Pre- and post-surgery echocardiography measurements were collected, and adverse LVR was defined as a>15% increase in left ventricular end-diastolic volume or >10% decrease in left ventricular ejection fraction. Binary regression analysis was used to determine independent predictors of poor left ventricular remodeling.

Results

The variables associated with adverse LVR in this study were LVGLS (P<0.001, odds ratio: 1.996, 95% CI: 1.394-2.856) and MD (P=0.011, odds ratio: 1.031, 95% CI: 1.007-1.055). The poorly reconstructed group had lower absolute values of LVGLS and higher MD than the healthy control group and the non-poorly reconstructed group. A LVGLS cutoff of -15.0% was the best predictor for patients with poorly reconstructed LVR (sensitivity: 75.7%; specificity: 100.0%; AUC: 0.93), and a MD cutoff of 63.8ms was the best predictor (sensitivity: 63.8%; specificity: 98.6%; AUC: 0.88).

Conclusion

Speckle tracking echocardiography has potential value for predicting the progression of adverse LVR and for identifying non-responders among patients with RMS undergoing surgery.

Highlighting Fibroblasts Activation in Fibrosis: The State-of-The-Art Fibroblast Activation Protein Inhibitor PET Imaging in Cardiovascular Diseases

Fibrosis is a common healing process that occurs during stress and injury in cardiovascular diseases. The evolution of fibrosis is associated with cardiovascular disease states and causes adverse effects. Fibroblast activation is responsible for the formation and progression of fibrosis. The incipient detection of activated fibroblasts is important for patient management and prognosis. Fibroblast activation protein (FAP), a membrane-bound serine protease, is almost specifically expressed in activated fibroblasts. The development of targeted FAP-inhibitor (FAPI) positron emission tomography (PET) imaging enabled the visualisation of FAP, that is, incipient fibrosis. Recently, research on FAPI PET imaging in cardiovascular diseases increased and is highly sought. Hence, we comprehensively reviewed the application of FAPI PET imaging in cardiovascular diseases based on the state-of-the-art published research. These studies provided some insights into the value of FAPI PET imaging in the early detection of cardiovascular fibrosis, risk stratification, response evaluation, and prediction of the evolution of left ventricular function. Future studies should be conducted with larger populations and multicentre patterns, especially for response evaluation and outcome prediction.

Heart failure with preserved ejection fraction is the most frequent but commonly overlooked phenotype in patients on chronic hemodialysis

Introduction

Heart failure (HF) is a serious complication of end-stage kidney disease (ESKD). However, most data come from retrospective studies that included patients on chronic hemodialysis at the time of its initiation. These patients are frequently overhydrated, which significantly influences the echocardiogram findings. The primary aim of this study was to analyze the prevalence of heart failure and its phenotypes. The secondary aims were (1) to describe the potential of N-terminal pro-brain natriuretic peptide (NTproBNP) for HF diagnosis in ESKD patients on hemodialysis, (2) to analyze the frequency of abnormal left ventricular geometry, and (3) to describe the differences between various HF phenotypes in this population.

Methods

We included all patients on chronic hemodialysis for at least 3 months from five hemodialysis units who were willing to participate, had no living kidney transplant donor, and had a life expectancy longer than 6 months at the time of inclusion. Detailed echocardiography together with hemodynamic calculations, dialysis arteriovenous fistula flow volume calculation, and basic lab analysis were performed in conditions of clinical stability. Excess of severe overhydration was excluded by clinical examination and by employing bioimpedance.

Results

A total of 214 patients aged 66.4 ± 14.6 years were included. HF was diagnosed in 57% of them. Among patients with HF, HF with preserved ejection fraction (HFpEF) was, by far, the most common phenotype and occurred in 35%, while HF with reduced ejection fraction (HFrEF) occurred only in 7%, HF with mildly reduced ejection fraction (HFmrEF) in 7%, and high-output HF in 9%. Patients with HFpEF differed from patients with no HF significantly in the following: they were older (62 ± 14 vs. 70 ± 14, p = 0.002) and had a higher left ventricular mass index [96(36) vs. 108(45), p = 0.015], higher left atrial index [33(12) vs. 44(16), p < 0.0001], and higher estimated central venous pressure [5(4) vs. 6(8), p = 0.004] and pulmonary artery systolic pressure [31(9) vs. 40(23), p = 0.006] but slightly lower tricuspid annular plane systolic excursion (TAPSE): 22 ± 5 vs. 24 ± 5, p = 0.04. NTproBNP had low sensitivity and specificity for diagnosing HF or HFpEF: with the use of the cutoff value of 8,296 ng/L, the sensitivity of HF diagnosis was only 52% while the specificity was 79%. However, NTproBNP levels were significantly related to echocardiographic variables, most significantly to the indexed left atrial volume (R = 0.56, p < 10^-5) and to the estimated systolic pulmonary arterial pressure (R = 0.50, p < 10^-5).

Conclusions

HFpEF was by far the most common heart failure phenotype in patients on chronic hemodialysis and was followed by high-output HF. Patients suffering from HFpEF were older and had not only typical echocardiographic changes but also higher hydration that mirrored increased filling pressures of both ventricles than in those of patients without HF.

Predicting Left Ventricular Myocardial Fibrosis in Patients with Hypertrophic Cardiomyopathy by Speckle Tracking Automated Functional Imaging

OBJECTIVE

The study was performed to explore the predictive value of multiple strain parameters for myocardial fibrosis in patients with hypertrophic cardiomyopathy (HCM) by using speckle tracking automated functional imaging (AFI).

METHODS

A total of 61 patients diagnosed with HCM were finally enrolled in this study. All patients completed transthoracic echocardiography and cardiac magnetic resonance late gadolinium enhancement (LGE) within 1 month. Twenty age- and sex-matched healthy participants were included as the control group. Multiple parameters, including segmental longitudinal strain (LS), global longitudinal strain (GLS), post-systolic index and peak strain dispersion, were automatically analyzed by AFI.

RESULTS

A total of 1458 myocardial segments were analyzed according to the left ventricular 18-segment model. Among the 1098 segments from HCM patients, segments with LGE had a lower absolute value of segmental LS than those without LGE (p < 0.05). The cutoff values of segmental LS for predicting positive LGE in the basal, intermediate and apical regions were -12.5%, -11.5% and -14.5%, respectively. GLS could predict significant myocardial fibrosis (≥2 positive LGE segments) at a cutoff value of -16.5% with a sensitivity of 80.9% and specificity of 76.5%. As an independent predictor of significant myocardial fibrosis, GLS was substantially associated with the severity of myocardial fibrosis and 5 years sudden cardiac death risk score in HCM patients.

CONCLUSION

Speckle tracking AFI could efficiently identify left ventricular myocardial fibrosis in patients with HCM by multiple parameters. GLS predicted significant myocardial fibrosis at a cutoff value of -16.5%, which may indicate the adverse clinical outcomes in HCM patients.

Clinical Utility of Strain Imaging in Assessment of Myocardial Fibrosis

Myocardial fibrosis (MF) is a non-reversible process that occurs following acute or chronic myocardial damage. MF worsens myocardial deformation, remodels the heart and raises myocardial stiffness, and is a crucial pathological manifestation in patients with end-stage cardiovascular diseases and closely related to cardiac adverse events. Therefore, early quantitative analysis of MF plays an important role in risk stratification, clinical decision, and improvement in prognosis. With the advent and development of strain imaging modalities in recent years, MF may be detected early in cardiovascular diseases. This review summarizes the clinical usefulness of strain imaging techniques in the non-invasive assessment of MF.

Left Atrial Remodeling in Response to Aortic Valve Replacement: Pathophysiology and Myocardial Strain Analysis

Severe aortic stenosis (AS) is the most common valve disease in the elderly and is associated with poor prognosis if treated only medically. AS causes chronic pressure overload, concentric left ventricular (LV) hypertrophy, myocardial stiffness, and diastolic dysfunction. This adverse remodeling also affects the left atrium (LA), which dilates and develops myocardial fibrosis, with a reduction in intrinsic function and a consequent high risk of the development of atrial fibrillation. Speckle-tracking echocardiography is able to detect myocardial dysfunction before other conventional parameters, such as LV ejection fraction, and also predict clinical outcomes. This review aims at describing LV and LA remodeling in AS and before and after aortic valve replacement and the usefulness of myocardial strain analysis in this clinical setting.

Detection of myocardial fibrosis: Where we stand

Myocardial fibrosis, resulting from the disturbance of extracellular matrix homeostasis in response to different insults, is a common and important pathological remodeling process that is associated with adverse clinical outcomes, including arrhythmia, heart failure, or even sudden cardiac death. Over the past decades, multiple non-invasive detection methods have been developed. Laboratory biomarkers can aid in both detection and risk stratification by reflecting cellular and even molecular changes in fibrotic processes, yet more evidence that validates their detection accuracy is still warranted. Different non-invasive imaging techniques have been demonstrated to not only detect myocardial fibrosis but also provide information on prognosis and management. Cardiovascular magnetic resonance (CMR) is considered as the gold standard imaging technique to non-invasively identify and quantify myocardial fibrosis with its natural ability for tissue characterization. This review summarizes the current understanding of the non-invasive detection methods of myocardial fibrosis, with the focus on different techniques and clinical applications of CMR.

Molecular Approaches and Echocardiographic Deformation Imaging in Detecting Myocardial Fibrosis

The pathological remodeling of myocardial tissue is the main cause of heart diseases. Several processes are involved in the onset of heart failure, and the comprehension of the mechanisms underlying the pathological phenotype deserves special attention to find novel procedures to identify the site of injury and develop novel strategies, as well as molecular druggable pathways, to counteract the high degree of morbidity associated with it. Myocardial fibrosis (MF) is recognized as a critical trigger for disruption of heart functionality due to the excessive accumulation of extracellular matrix proteins, in response to an injury. Its diagnosis remains focalized on invasive techniques, such as endomyocardial biopsy (EMB), or may be noninvasively detected by cardiac magnetic resonance imaging (CMRI). The detection of MF by non-canonical markers remains a challenge in clinical practice. During the last two decades, two-dimensional (2D) speckle tracking echocardiography (STE) has emerged as a new non-invasive imaging modality, able to detect myocardial tissue abnormalities without specifying the causes of the underlying histopathological changes. In this review, we highlighted the clinical utility of 2D-STE deformation imaging for tissue characterization, and its main technical limitations and criticisms. Moreover, we focalized on the importance of coupling 2D-STE examination with the molecular approaches in the clinical decision-making processes, in particular when the 2D-STE does not reflect myocardial dysfunction directly. We also attempted to examine the roles of epigenetic markers of MF and hypothesized microRNA-based mechanisms aiming to understand how they match with the clinical utility of echocardiographic deformation imaging for tissue characterization and MF assessment.

A Heart Segmentation Algorithm Based on Dynamic Ultrasound

The heart is one of the most important organs of the human body. The role of the heart is to promote blood flow and provide sufficient blood flow to organs and tissues. The research on the heart has important theoretical and clinical significance. Because of the noninvasive and intuitive display of ultrasound image, it can dynamically obtain the heart state and has become the main means to detect the heart dynamics. We analyze the characteristics of cardiac ultrasound image from the medical point of view and signal processing. The heart movement is periodic and rhythmic. The image signal can be decomposed. Firstly, the image is decomposed into high- and low-frequency signals to highlight different dimensional information. Then, the attention model was introduced, focusing on the heart region. Finally, the multidimensional network carrying model was established to achieve cardiac segmentation. The experimental results show that the AOM of the algorithm proposed in this paper reaches 92%, which has a certain degree of advancement and can assist doctors to make accurate diagnosis.