A Test in Context: Myocardial Strain Measured by Speckle-Tracking Echocardiography

Advanced myocardial characterization and function with cardiac CT

Non-invasive imaging with characterization and quantification of the myocardium with computed tomography (CT) became feasible owing to recent technical developments in CT technology. Cardiac CT can serve as an alternative modality when cardiac magnetic resonance imaging and/or echocardiography are contraindicated, not feasible, inconclusive, or non-diagnostic. This review summarizes the current and potential future role of cardiac CT for myocardial characterization including a summary of late enhancement techniques, extracellular volume quantification, and strain analysis. In addition, this review highlights potential fields for research about myocardial characterization with CT to possibly include it in clinical routine in the future.

Impact of Aficamten on Echocardiographic Cardiac Structure and Function in Symptomatic Obstructive Hypertrophic Cardiomyopathy

BACKGROUND

Aficamten, a next-in-class cardiac myosin inhibitor, improved peak oxygen uptake (pVO2) and lowered resting and Valsalva left ventricular outflow (LVOT) gradients in adults with symptomatic obstructive hypertrophic cardiomyopathy (oHCM) in SEQUOIA-HCM (Phase 3 Trial to Evaluate the Efficacy and Safety of Aficamten Compared to Placebo in Adults With Symptomatic oHCM), a phase 3, multicenter, randomized, double-blinded, placebo-controlled study.

OBJECTIVES

The authors sought to evaluate the effect of aficamten on echocardiographic measures of cardiac structure and function in SEQUOIA-HCM.

METHODS

Serial echocardiograms were performed over 28 weeks in patients randomized to receive placebo or aficamten in up to 4 individually titrated escalating doses (5-20 mg daily) over 24 weeks based on Valsalva LVOT gradients and left ventricular ejection fraction (LVEF).

RESULTS

Among 282 patients (mean age 59 ± 13 years; 41% female, 79% White, 19% Asian), mean LVEF was 75% ± 6% with resting and Valsalva LVOT gradients of 55 ± 30 mm Hg and 83 ± 32 mm Hg, respectively. Over 24 weeks, aficamten significantly lowered resting and Valsalva LVOT gradients, and improved left atrial volume index, lateral and septal e' velocities, and lateral and septal E/e' (all P ≤ 0.001). LV end-systolic volume increased and wall thickness decreased (all P ≤ 0.003). Aficamten resulted in a mild reversible decrease in LVEF (-4.8% [95% CI: -6.4 to -3.3]; P < 0.001) and absolute LV global circumferential strain (-3.7% [95% CI: 1.8-5.6]; P < 0.0010), whereas LV global longitudinal strain was unchanged. Several measures, including LVEF, LVOT gradients, and E/e' returned to baseline following washout. Among those treated with aficamten, improved pVO2 and reduction in N-terminal pro-B-type natriuretic peptide (NT-proBNP) were associated with improvement in lateral e' velocity and septal and lateral E/e' (all P < 0.03), whereas improvement in Kansas City Cardiomyopathy Questionnaire Clinical Summary Scores (KCCQ-CSS) was associated with a decrease in both LVOT gradients (all P < 0.001).

CONCLUSIONS

Compared with placebo, patients receiving aficamten demonstrated significant improvement in LVOT gradients and measures of LV diastolic function, and several of these measures were associated with improvements in pVO2, KCCQ-CSS, and NT-proBNP. A modest decrease in LVEF occurred yet remained within normal range. These findings suggest aficamten improved multiple structural and physiological parameters in oHCM without significant adverse changes in LV systolic function. (Phase 3 Trial to Evaluate the Efficacy and Safety of Aficamten Compared to Placebo in Adults With Symptomatic oHCM [SEQUOIA-HCM]; NCT05186818).

Contemporary Multimodality Imaging for Diagnosis and Management of Fabry Cardiomyopathy

Fabry disease (FD) is an X-linked lysosomal storage disorder which leads to the accumulation of globotriaosylceramide (Gb3) in various organs, including the heart. FD can be subdivided into classic disease resulting from negligible residual enzyme activity and a milder, atypical phenotype with later onset and less severe clinical presentation. The use of multimodality cardiac imaging including echocardiography, cardiac magnetic resonance and nuclear imaging is important for the diagnostic and prognostic evaluation in these patients. There are gaps in the literature regarding the comprehensive description of cardiac findings of FD and its evaluation by multimodality imaging. In this review, we describe the contemporary practices and roles of multimodality cardiac imaging in individuals affected with Fabry disease.

Multidirectional myocardial function in bicuspid aortic valve stenosis patients: a three-dimensional speckle tracking analysis

Purpose

The impact of aortic stenosis (AS) severity on multidirectional myocardial function in patients with bicuspid aortic valve (BAV) remains unclear, despite the recognized presence of early left ventricular longitudinal myocardial dysfunction in BAV patients with normal valve function. The aim of the study was to evaluate the multidirectional myocardial functions of BAV patients.

Methods

A total of 86 BAV patients (age 46.71 ± 13.62 years, 69.4% men) with normally functioning (BAV-nf), mild AS, moderate AS, and severe AS with preserved left ventricular ejection fraction (LVEF ≥ 52%) were included. 30 healthy volunteers were recruited as the control group. Multidirectional strain and volume analysis were performed by three-dimensional speckle tracking echocardiography(3D-STE).

Results

Global longitudinal strain (GLS), and global radial strain (GRS) were reduced in BAV-nf patients compared with the controls. With each categorical of AS severity from BAV-nf to severe AS, there was an associated progressive impairment of GLS and GRS (all P < 0.001). Global circumferential strain (GCS) did not show a significant decrease from BAV-nf to mild AS but began to decrease from moderate AS. Multiple linear regressions indicated that indexed aortic valve area (AVA/BSA), as a measure of AS severity, was an independent determinant of GLS, GCS and GRS.

Conclusions

Left ventricular longitudinal myocardial reduction is observed even in patients with well-functioning bicuspid aortic valves. With each categorical increase in the grade of AS severity from normally functioning to severe aortic stenosis, there was an associated progressive impairment of longitudinal myocardial function. Furthermore, circumferential myocardial function was starting damaged from moderate AS. AVA/BSA was independently associated with multidirectional myocardial function injuries.

Global longitudinal strain and the risk of major adverse cardiac events in post-myocardial infarction patients: A retrospective cohort study

BACKGROUND

This study evaluates the relationship between global longitudinal strain (GLS) and late major adverse cardiovascular events (MACEs) in patients after acute myocardial infarction (AMI).

METHODS

Data of newly diagnosed AMI patients between March 2010 and July 2014 were retrospectively evaluated. The patients underwent serial echocardiography at admission and at third and sixth months post-admission. We calculated GLS by averaging the strain from all myocardial segments using speckle-tracking echocardiography (STE). We used multivariate Cox regression analysis and receiver operating characteristic (ROC) curve analyses to assess the relationship between GLS at admission and late MACEs.

RESULTS

Eighty-nine newly diagnosed AMI patients were enrolled. The average age at diagnosis was 61 ± 12.5 years, and approximately 89.9% of the patients were men. The average level of GLS was -17.5 ± 3.9%. The overall prevalence of MACEs was 23.6% (21/89), compared with 44% (11/25) in the group with GLS≥-15% and 17.9% (5/28) in the group with GLS<-20%. GLS was positively linked with MACEs in the fully adjusted Cox proportional hazard model (hazard ratio [HR], 1.19; 95% confidence interval [CI], 1.04-1.37; P=0.014) after adjusting potential confounders. The ROC curve analysis for one year MACEs between GLS at admission, with the most significant area under the curve(AUC) 78.1% (95% CI, 63.8% - 92.6%).

CONCLUSIONS

Myocardial dysfunction, characterized by impaired GLS, is often observed in AMI patients, and a decrease in GLS levels at admission were associated with an increased risk of long-term MACEs in post-myocardial infarction patients.

Use of Speckle-Tracking Echocardiography in Septic Cardiomyopathy in Critically Ill Children: A Narrative Review

OBJECTIVES

In critically ill children with severe sepsis, septic cardiomyopathy (SCM) denotes the subset of patients who have myocardial dysfunction with poor response to fluid and inotropic support, and higher mortality risk. The objective of this review was to evaluate the role of speckle-tracking echocardiography (STE) in the diagnosis and prognosis of pediatric SCM in the PICU setting.

DATA SOURCES

We performed detailed searches using PubMed, Scopus, Web of Science, and Google Scholar. Reference lists of all included studies were also examined for further identification of potentially relevant studies.

STUDY SELECTION

Studies with the following medical subject headings and keywords were selected: speckle-tracking echocardiography, strain imaging, global longitudinal strain, echocardiography, sepsis, severe sepsis, septic shock, septic cardiomyopathy, and myocardial dysfunction.

DATA EXTRACTION

The following data were extracted from all included studies: demographics, diagnoses, echocardiographic parameters, severity of illness, PICU management, and outcomes.

DATA SYNTHESIS

STE is a relatively new echocardiographic technique that directly quantifies myocardial contractility. It has high sensitivity in diagnosing SCM, correlates well with illness severity, and has good prognosticating value as compared with conventional echocardiographic parameters. Further studies are required to establish its role in evaluating biventricular systolic and diastolic dysfunction, and to investigate whether it has a role in individualizing treatment and improving treatment outcomes in this group of patients.

CONCLUSIONS

STE is a useful adjunct to conventional measures of cardiac function on 2D-echocardiography in the assessment of pediatric SCM in the PICU.

Preoperative right ventricular strain as an early predictor of perioperative cardiac failure in patients undergoing mitral surgery: An exploratory study

Objectives

This study's primary purpose was to demonstrate the correlation of preoperative right ventricular free-wall longitudinal strain (RVFWLS) and pre-/postsurgical variation in strain (delta strain) with the clinical and echocardiographic diagnosis of right ventricular dysfunction. Its secondary purpose was to determine the correlation of RVFWLS and delta strain with length of stay (LOS) in the intensive care unit (ICU), ventilation days, trend of natriuretic peptide test. (NT-proBNP) and lactate in the first 48 h, incidence of acute renal failure, and 28-day mortality.

Design

Prospective observational study.

Setting

Cardio-thoracic and Vascular Anaesthesia Department and ICU of the University Hospital Integrated Trust of Verona.

Participants

Patients scheduled for mitral surgery.

Interventions

None.

Measurements and Main Results

All clinical and transoesophageal echocardiographic (TEE) parameters were collected at baseline, before surgery (T1) and at admission in the ICU postsurgery (T2). During the postoperative period, the clinical and echocardiographic diagnoses of right, left, or biventricular dysfunction were evaluated. TEE parameters were evaluated by a cardiologist offline. The patients were divided into two subgroups according to the development of any type of ventricular dysfunction. No statistically significant differences emerged between the two groups. According to a logistic regression model, a T1-RVFWLS value of -15% appeared to predict biventricular dysfunction (sensitivity: 100%; specificity: 91.3%). No correlation between T1- or T2-RVFWLS and creatinine, hours of ventilation or ICU LOS was found.

Conclusions

Our study introduces a new parameter that could be used in perioperative evaluations to identify patients at risk of postoperative biventricular dysfunction.

Quantitative evaluation of adhesion severity around subscapularis and its relationship with shoulder range of motion in frozen shoulder and rotator cuff disorder: an observational study using dynamic ultrasonography

Background

This study aimed to evaluate the severity of adhesion between muscles in the shoulder joint using dynamic ultrasonography and to confirm whether adhesions cause range of motion (ROM) restrictions.

Methods

Twenty-four shoulders from 15 frozen shoulder patients and 24 shoulders from 18 rotator cuff disorder patients were enrolled. We obtained ultrasound video sequences of the subscapularis (SSC) and deltoid muscles during shoulder external rotation. The mean stretching velocities of the deltoid and SSC were subsequently analyzed using a personal computer. If adhesions occurred between both muscles, the deltoid was stretched more vigorously, and we calculated mean stretching velocity of the deltoid / SSC as adhesion severity. The coracohumeral ligament thickness was measured using the same images. Shoulder ROM was measured by using a universal goniometer.

Results

The intraclass correlation coefficients (1.1) and (2.1) of the adhesion severity measurements were 0.85 and 0.91, respectively. Multiple linear regression analysis revealed that the adhesion severity is a significant predictor for external rotation ROM in the rotator cuff disorder group (R2 = 0.44, F = 10.1, P < .01, t = -2.9), while coracohumeral ligament thickness predicts ROM in the frozen shoulder group (R2 = 0.28, F = 5.5, P = .01, t = -3.0).

Conclusion

The proposed method is reliable. Muscle adhesion causes ROM restriction of the shoulder joint. The primary cause of shoulder ROM restriction differed between the diagnostic groups.

Deficiency in Prader-Willi syndrome gene necdin leads to attenuated cardiac contractility

Prader-Willi syndrome (PWS) is a genetic disorder characterized by behavioral disturbances, hyperphagia, and intellectual disability. Several surveys indicate that PWS is also associated with cardiac abnormalities, possibly contributing to a high incidence of sudden death. However, the pathological mechanisms underlying cardiac dysfunction in PWS remain unclear. In this study, we found that deficiency in necdin, an intronless gene within PWS region, led to heart systolic and diastolic dysfunction in mice. Through yeast two-hybrid screening, we identified an interaction between necdin and non-muscle myosin regulatory light chain 12a/b (MYL12 A/B). We further showed that necdin stabilized MYL12 A/B via SGT1-heat shock protein 90 (HSP90) chaperone machinery. The zebrafish lacking the MYL12 A/B analog, MYL12.1, exhibited impaired heart function, while cardiac-specific overexpression of MYL12A normalized the heart dysfunction in necdin-deficient mice. Our findings revealed necdin dysfunction as a contributing factor to cardiomyopathy in PWS patients and emphasized the importance of HSP90 chaperone machinery and non-muscle myosin in heart fitness.

Prognostic Value of CT-Derived Myocardial Biomarkers: Extracellular Volume Fraction and Strain in Patients with Severe Aortic Stenosis Undergoing Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-analysis

RATIONALE AND OBJECTIVES

This study aimed to investigate the prognostic value of preoperative CT scan-derived myocardial biomarkers in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR).

MATERIALS AND METHODS

In April 2024, three databases (PubMed, Web of Science and Embase) were searched to identify studies. A random-effects model for meta-analysis was conducted to calculate pooled hazard ratios (HR) and 95% confidence intervals (CI) to assess the prognostic value. The I2 statistic was used to assess heterogeneity. Meta-regression analysis was conducted to appraise which variables yielded a significant impact on the HR of included biomarkers.

RESULTS

11 studies were identified, of which six studies involved 678 patients reporting extracellular volume fraction (ECV), one study involved 300 patients reporting ECV and left ventricular global longitudinal strain (LVGLS), three studies involved 868 patients reporting LVGLS and one study involved 376 patients reporting LVGLS and peak left atrial longitudinal strain (PALS). The endpoints included all-cause mortality, major adverse cardiovascular events (MACE) and a composite outcome of the previous two. The meta-analysis revealed that ECV, whether considered as a dichotomous variable (pooled HR: 3.87, 95% CI: 2.63-5.70, I2 = 0%), or as a continuous variable (pooled HR: 1.12, 95% CI: 1.05-1.19, I2 = 66%), and LVGLS, whether considered as a dichotomous variable (pooled HR: 1.70, 95% CI: 1.30-2.22, I2 = 0%) or a continuous variable (pooled HR: 1.07, 95% CI: 1.04-1.10, I2 = 0%) were all significant predictors for outcomes in patients with severe AS after TAVR. Age, sex, follow-up time and mean pressure gradient had a significant impact on the model of ECV (continuous).

CONCLUSION

The higher CT-derived ECV and impaired LVGLS are able to predict worse outcomes in patients with severe AS who have undergone TAVR.

Speckle-Tracking Echocardiography in Right Ventricular Function of Clinically Well Patients with Heart Transplantation

Heart transplantation (HT) is the mainstream therapy for end-stage heart disease. However, the cardiac graft function can be affected by several factors. It is important to monitor HT patients for signs of graft dysfunction. Transthoracic echocardiography is a simple, first-line, and non-invasive method for the assessment of cardiac function. The emerging speckle-tracking echocardiography (STE) could quickly and easily provide additive information over traditional echocardiography. STE longitudinal deformation parameters are markers of early impairment of ventricular function. Although once called the "forgotten ventricle", right ventricular (RV) assessment has gained attention in recent years. This review highlights the potentially favorable role of STE in assessing RV systolic function in clinically well HT patients.

Two-dimensional speckle-tracking echocardiography in left ventricular systolic function in patients with systemic lupus erythematosus

OBJECTIVES

To investigate whether two-dimensional speckle-tracking echocardiography (2DSTE) can be considered a criterion for early left ventricular (LV) systolic impairment in patients with systemic lupus erythematosus (SLE) and to further explore the association with each other.

METHODS

We included 38 patients with SLE and assessed the degree of disease activity according to the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) 2000 scoring criteria, together with 38 healthy controls who were matched by sex and age. Routine LV systolic function evaluation parameters were obtained by echocardiography as well as 2DSTE measurement of LV strain parameters to obtain global longitudinal strain (GLS) values, respectively.

RESULTS

(I) On routine LV function parameters such as ejection fractions (EF) and left ventricular end-diastolic internal diameter (LVIDd), the SLE group and the control group did not reflect differences. In contrast, on the LV strain parameter obtained from 2DSTE measurements, the GLS values in all cardiac planes were lower in the SLE group than in the control group and showed statistically significant differences. (II) Correlation analysis showed that there was a correlation between SLEDAI and GLS, especially a meaningful correlation with GLS Avg and GLS A4C, with correlation coefficients of 0.35 and 0.47, respectively.

CONCLUSIONS

The use of 2DSTE can detect early impaired LV systolic function in SLE patients, and GLS is progressively gaining attention as an indicator of subclinical myocardial injury and LV function in SLE patients. The correlation that exists between GLS and SLEDAI might contribute to a better assessment of cardiac involvement in SLE patients. Key Points • Cardiac involvement has become one of the major factors in the poor prognosis of SLE patients, which directly affects the mortality of SLE patients. Traditional echocardiography is difficult to detect early left ventricular function impairment, thus affecting clinicians' judgment and diagnosis. • 2DSTE can recognize subclinical myocardial injury in SLE patients at an early stage, and its derived strain parameters may be used as an indicator to evaluate myocardial involvement and reflect disease activity in SLE patients.

Association between speckle tracking echocardiography and pressure-volume loops during cardiogenic shock development

BACKGROUND

The relationship between speckle tracking assessed global longitudinal strain (GLS) and Doppler-based echocardiography with basic physiological markers of cardiac function derived from pressure-volume loops is poorly elucidated.

OBJECTIVE

We aimed to describe the association between LS and Doppler-based echocardiography and direct measurements of central haemodynamic parameters from conductance catheter-based pressure-volume loops in an animal model with increasing left ventricular (LV) dysfunction.

METHODS

12 Danish landrace female pigs (75-80 kg) were used. All instrumentations were performed percutaneously, including the conductance catheter in the LV. Progressive LV dysfunction was induced by embolisation through the left main coronary artery with microspheres every 3 min until a >50% reduction in cardiac output (CO) or mixed venous saturation (SvO2), compared with baseline, or SvO2 <30%. Echocardiography was performed at baseline and 90 s after each injection.

RESULTS

With progressive LV dysfunction, mean CO decreased from 5.6±0.9 L/min to 2.1±0.9 L/min, and mean SvO2 deteriorated from 61.1±7.9% to 35.3±6.1%. Mean LS and LV outflow tract velocity time integral (LVOT VTI) declined from -13.8±3.0% to -6.1±2.0% and 16.9±2.6 cm to 7.8±1.8 cm, respectively. LS and LVOT VTI showed the strongest correlation to stroke work in unadjusted linear regression (r2=0.53 and r2=0.49, respectively). LS correlated significantly with stroke volume, end-systolic elastance, systolic blood pressure, ventriculo-arterial coupling and arterial elastance.

CONCLUSION

In an animal model of acute progressive LV dysfunction, echocardiographic and conductance catheter-based measurements changed significantly. LS and LVOT VTI displayed the earliest and the largest alterations with increased myocardial damage and both correlated strongest with stroke work.

Comparative analysis of left ventricle function and deformation imaging in short and long axis plane in cardiac magnetic resonance imaging

Background

Advancements in cardiac imaging have revolutionized our understanding of ventricular contraction. While ejection fraction (EF) is still the gold standard parameter to assess left ventricle (LV) function, strain imaging (SI) has provided valuable insights into ventricular mechanics. The lack of an integrative method including SI parameters in a single, validated formula may limit its use. Our aim was to compare different methods for evaluating global circumferential strain (GCS) and their relationship with global longitudinal strain (GLS) and EF in CMR and how the different evaluations fit in the theoretical relationship between EF and global strain.

Methods

Retrospective monocenter study. Inclusion of every patient who underwent a CMR during a 15 months period with various clinical indication (congenital heart defect, myocarditis, cardiomyopathy). A minimum of three LV long-axis planes and a stack of short-axis slices covering the LV using classical steady-state free precession cine sequences. A single assessment of GLS on long axis (LAX) slices and a double assessment of GCS and EF with both short axis (SAX) and LAX slices were made by a single experienced CMR investigator.

Results

GCS-SAX and GCS-LAX were correlated (r = 0.77, P < 0.001) without being interchangeable with a high reproducibility for GCS, GLS and EF. EF calculated from LAX images showed an overestimation compared to EF derived from SAX images of 7%. The correlation between calculated EF and theoretical EF derived from SI was high (r = 0.88 with EF-SAX, 0.95 with EF-LAX).

Data conclusion

This study highlights the need to integrate strain imaging techniques into clinical by incorporating strain parameters into EF calculations, because it gives a deeper understanding of cardiac mechanics.

Prognostic impact of MRI-derived feature tracking myocardial strain in patients with non-ischaemic dilated cardiomyopathy: a systematic review and meta-analysis

AIM

To evaluate the clinical utility of feature tracking (FT)-derived myocardial strain in patients with non-ischaemic dilated cardiomyopathy (NIDCM).

MATERIALS AND METHODS

Electronic database searches of PubMed, Web of Science Core Collection, Cochrane advanced search, and EMBASE were performed. Studies on NIDCM were divided into categories according to left ventricular ejection fraction (LVEF; <30%, 30-40%, >40%), and correlations between strains and prevalence of late gadolinium enhancement (LGE) were evaluated by weighted correlation coefficients. Global longitudinal strain (GLS) hazard ratios were also integrated for prediction of future adverse events.

RESULTS

The present meta-analysis analysed data from 5,767 patients with NIDCM from 30 eligible studies. GLS and global circumferential strain significantly differed across the three LVEF categories (all p<0.05); however, global radial strain did not. Only GLS showed a strong correlation with the prevalence of LGE (Spearman's correlation coefficient = 0.61). The pooled HR of GLS for predicting adverse events was 1.15 (95% confidence interval [CI]: 1.07-1.23, p<0.001).

CONCLUSION

In this meta-analysis, FT-derived GLS was strongly correlated with myocardial fibrosis and was an important predictor of future adverse events. These results suggest that FT-derived GLS may be useful in the pathological evaluation and risk stratification of NIDCM.

Evaluation the Effect of Anthracyclines on Cardiac Function in Children Lymphoma Survivors by Left Ventricular Myocardial Work

Anthracycline chemotherapy is associated with the left ventricular (LV) dysfunction, but the conventional echocardiographic parameter is insensitive in detecting subclinical cardiac dysfunction, and the role of echocardiography in children cancer survivors (CCSs) has not been well established. Here, the myocardial work (MW) was employed to evaluate the early effect of the anthracyclines on LV function in children lymphoma survivors, as well as to explore the clinical application value of this modality. 51 children lymphoma survivors treated with anthracyclines were included. During the treatments, the echocardiography was performed at baseline (T0 phase), the 3rd (T1 phase) and 6th (T2 phase) chemotherapeutic cycle, respectively. After that, the conventional echocardiographic parameters, LV global longitudinal strain (GLS), and global myocardial work (GMW) parameters were obtained. Finally, these echocardiographic parameters were compared to distinguish the differences among three groups, and correlation analysis was used to identify relationship between GMW parameters and LV GLS. Compared with the baseline, we found that there are no significant differences for LVEF and other conventional echocardiographic parameters after chemotherapy, but the value of LV lateral E/E' increased at T1 and T2 group. The GLS, global work index, global constructed work, and global work efficiency were decreased, while the global wasted work was increased after chemotherapy (all P < 0.05). The correlation analysis showed that the GLS has significant correlation with GMW parameters (all P < 0.001). The MW, as a new noninvasive echocardiography modality, could be used to quantitatively evaluate the LV MW in children lymphoma survivors treated with anthracyclines, which providing a sensitive method to early detect the children's LV dysfunction after the chemotherapy.

Ablation-induced left atrial mechanical dysfunction recovers in weeks after ablation

BACKGROUND

The immediate impact of catheter ablation on left atrial mechanical function and the timeline for its recovery in patients undergoing ablation for atrial fibrillation (AF) remain uncertain. The mechanical function response to catheter ablation in patients with different AF types is poorly understood.

METHODS

A total of 113 AF patients were included in this retrospective study. Each patient had three magnetic resonance imaging (MRI) studies in sinus rhythm: one pre-ablation, one immediate post-ablation (within 2 days after ablation), and one post-ablation follow-up MRI (≤ 3 months). We used feature tracking in the MRI cine images to determine peak longitudinal atrial strain (PLAS). We evaluated the change in strain from pre-ablation, immediately after ablation to post-ablation follow-up in a short-term study (< 50 days) and a 3-month study (3 months after ablation).

RESULTS

The PLAS exhibited a notable reduction immediately after ablation, compared to both pre-ablation levels and those observed in follow-up studies conducted at short-term (11.1 ± 9.0 days) and 3-month (69.6 ± 39.6 days) intervals. However, there was no difference between follow-up and pre-ablation PLAS. The PLAS returned to 95% pre-ablation level within 10 days. Paroxysmal AF patients had significantly higher pre-ablation PLAS than persistent AF patients in pre-ablation MRIs. Both type AF patients had significantly lower immediate post-ablation PLAS compared with pre-ablation and post-ablation PLAS.

CONCLUSION

The present study suggested a significant drop in PLAS immediately after ablation. Left atrial mechanical function recovered within 10 days after ablation. The drop in PLAS did not show a substantial difference between paroxysmal and persistent AF patients.

Prevalence and risk factors for cirrhotic cardiomyopathy: a prospective cross-sectional study

BACKGROUND

This study aimed to assess cardiac structure and function in patients with cirrhosis, to investigate the prevalence of cirrhotic cardiomyopathy (CCM) in patients with cirrhosis of different etiologies and to analyze the risk factors for the development of CCM.

METHODS

This study selected cirrhotic patients aged 18-75 years who were hospitalized in Qilu Hospital of Shandong University. Patients with known heart disease, chronic lung disease, severe renal insufficiency, malignancy, thyroid disease, hypertension, diabetes or pregnancy were excluded. A total of 131 patients with cirrhosis were finally included. Based on the results of echocardiography, patients who met the diagnostic definition of CCM were included in the CCM group, otherwise, they were classified as the non-CCM group. The demographic and clinical data of the two groups were compared, and the clinical characteristics and risk factors of CCM were evaluated.

RESULTS

The overall prevalence of CCM was 24.4%, and the occurrence of CCM was not related to the etiology of liver cirrhosis. The prevalence of CCM was significantly higher among cirrhotic patients complicated with ascites (31.4% vs. 16.4%; P  = 0.046) or with portal vein thrombosis (PVT) (42.9% vs. 17.1%; P  = 0.003). Older age [odds ratio (OR) = 1.058; 95% confidence interval (CI), 1.005-1.113; P  = 0.032] and PVT (OR = 2.999; 95% CI, 1.194-7.533; P  = 0.019) were independent risk factors for the development of CCM.

CONCLUSION

The prevalence of CCM in cirrhotic patients was 24.4%, and the occurrence of CCM was not related to the etiology of cirrhosis. The prevalence of CCM was higher in cirrhotic patients with ascites or PVT. Older age and PVT are independent risk factors for CCM, but validation in larger sample studies is still needed.

Blueberry-on-Top Phenomenon in Apical Variant Hypertrophic Cardiomyopathy

•“Inverse-amyloid” or “blueberry-on-top” strain pattern is a finding in AHCM. •The time to peak strain parametric map is the best depiction of this unique pattern. •This pattern provides a supportive diagnostic feature of apical variant HCM.

Obesity Predisposes Anthracycline-Treated Survivors of Childhood and Adolescent Cancers to Subclinical Cardiac Dysfunction

Anthracyclines are effective chemotherapeutics used in approximately 60% of pediatric cancer cases but have a well-documented risk of cardiotoxicity. Existing cardiotoxicity risk calculators do not include cardiovascular risk factors present at the time of diagnosis. The goal of this study is to leverage the advanced sensitivity of strain echocardiography to identify pre-existing risk factors for early subclinical cardiac dysfunction among anthracycline-exposed pediatric patients. We identified 115 pediatric patients with cancer who were treated with an anthracycline between 2013 and 2019. Peak longitudinal left ventricular strain was retroactively calculated on 495 surveillance echocardiograms via the TOMTEC AutoSTRAIN software. Cox proportional hazards models were employed to identify risk factors for abnormal longitudinal strain (> - 16%) following anthracycline treatment. High anthracycline dose (≥ 250 mg/m2 doxorubicin equivalents) and obesity at the time of diagnosis (BMI > 95th percentile-for-age) were both significant predictors of abnormal strain with hazard ratios of 2.79, 95% CI (1.07-7.25), and 3.85, 95% CI (1.42-10.48), respectively. Among pediatric cancer survivors, patients who are obese at the time of diagnosis are at an increased risk of sub-clinical cardiac dysfunction following anthracycline exposure. Future studies should explore the incidence of symptomatic cardiomyopathy 10-15 years post-treatment among patients with early subclinical cardiac dysfunction.

Influence of Obstructive Apnea Index on Persistent Left Ventricular Dysfunction in Patients with ST-Segment Elevation Myocardial Infarction

Background: We retrospectively investigated the effects of the severity and classification of sleep-disordered breathing (SDB) on left ventricular (LV) function in patients with ST-segment elevation myocardial infarction (STEMI). Methods: A total of 115 patients with STEMIs underwent a sleep study using a multichannel frontopolar electroencephalography recording device (Sleep Profiler) one week after STEMI onset. We evaluated LV global longitudinal strain (LV-GLS) using two-dimensional echocardiography at one week and seven months. Patients were classified as no SDB (AHI < 5 events/h), obstructive SDB (over 50% of apnea events are obstructive), and central SDB (over 50% of apnea events are central). Due to the device's limitations in distinguishing obstructive from central hypopnea, SDB classification was based on apnea index percentages. Results: The obstructive apnea index (OAI) was significantly associated with LV-GLS at one week (r = 0.24, p = 0.027) and seven months (r = 0.21, p = 0.020). No such correlations were found for the central apnea index and SDB classification. Multivariable regression analysis showed that the OAI was independently associated with LV-GLS at one week (β = 0.24, p = 0.002) and seven months (β = 0.20, p = 0.008). Conclusions: OAI is associated with persistent LV dysfunction assessed by LV-GLS in STEMI.

Assessment of left ventricular global longitudinal strain in patients with hypertrophic cardiomyopathy and coronary artery disease

Impaired left ventricular global longitudinal strain (GLS) and coronary artery disease (CAD) each confer adverse prognosis in hypertrophic cardiomyopathy (HCM). Despite their prevalence, data on GLS in co-existent HCM and CAD is lacking. Ninety-six patients with HCM and CAD were retrospectively identified between 2005 and 2021, and analyzed using 2D speckle-tracking echocardiography. Obstructive and non-obstructive CAD patients were compared, multivariate linear regression tested associations between clinical and echocardiographic variables with GLS, and Receiver Operating Characteristic Curve assessed the utility of GLS to predict all-cause mortality at follow-up. Mean age was 71 ± 12.2 years, 41% had obstructive HCM, 78% had obstructive CAD, and 75% had prior acute coronary syndrome. At 4.8-year follow-up, GLS decreased compared with baseline (- 12.5 ± 4.5 vs. - 14 ± 4.2%, p = 0.007), with basal segments experiencing the greatest impairment. GLS was lower in obstructive versus non-obstructive CAD patients at follow-up, although the magnitude was attenuated (baseline: - 13.2 vs. - 17.1%, p < 0.001; follow-up: - 12 vs. - 14.1%, p = 0.05). Interventricular septal thickness (β = 0.54), apical HCM (β = 0.48), and right ventricular systolic pressure (β = 0.39) were associated with more impaired GLS (all p < 0.001), independent of obstructive CAD (β = 0.09, p = 0.44). There were 9 follow-up deaths, with baseline GLS > - 13.5% being a good predictor of all-cause mortality (AUC 0.78, 95% CI 0.64-0.92, sensitivity 88%, specificity 57%, p = 0.01). Patients with HCM and CAD experience progressive GLS impairment over long-term follow-up, with GLS > - 13.5% appearing to be a threshold for predicting all-cause mortality. Apical HCM phenotype is independently associated with worse GLS.

The Contemporary Role of Speckle Tracking Echocardiography in Cirrhotic Cardiomyopathy

Cirrhotic cardiomyopathy (CCM) is characterized by elevated cardiac output at rest, an inability to further increase contractility under stress, and diastolic dysfunction. The diagnosis of CCM is crucial as it can lead to complications during liver transplantation. However, its recognition poses challenges with conventional echocardiography techniques. Speckle tracking echocardiography (STE), particularly global longitudinal strain (GLS), is a novel index that enhances the diagnostic efficacy of echocardiography for both ischemic and non-ischemic cardiomyopathies. GLS proves more sensitive in identifying early systolic dysfunction and is also influenced by advanced diastolic dysfunction. Consequently, there is an expanding scope for GLS utilization in cirrhotic cases, with newly updated diagnostic criteria for CCM incorporating GLS. Specifically, systolic dysfunction is now defined as either a left ventricular ejection fraction below 50% or an absolute GLS below 18%. However, conflicting data on GLS alterations in liver cirrhosis patients persist, as many individuals with advanced disease and a poor prognosis exhibit a hyperdynamic state with preserved or increased GLS. Consequently, the presence of CCM, according to the updated criteria, does not exhibit a significant association-in the majority of studies-with the severity of liver disease and prognosis. Furthermore, information on other indices measured with STE, such as left atrial and right ventricular strain, is promising but currently limited. This review aims to offer a critical assessment of the existing evidence concerning the application of STE in patients with liver cirrhosis.

Ultrasound study of right ventricular myocardial perfusion and functional changes in hypertrophic cardiomyopathy

BACKGROUND

To evaluate the changes of right ventricular (RV) myocardial perfusion and function in patients with hypertrophic cardiomyopathy (HCM) by myocardial contrast echocardiography (MCE) and speckle tracking (2D-STE), and to explore the relationship between RV myocardial perfusion and strain.

METHODS

Conventional ultrasound, MCE and 2D-STE were performed on 29 HCM patients and 21 healthy subjects to analyze RV myocardial perfusion, RV global strain, RV free wall strain, and strain of each segment. The correlation between RV myocardial perfusion and strain was further analyzed in HCM patients.

RESULTS

MCE results showed that the regional myocardial perfusion of the RV in HCM patients was decreased. Compared with the normal control group, the mean slope (β) in the middle and apical segments of the RV free wall, and the peak intensity (A), β, myocardial blood flow (MBF) of the ventricular septum decreased in HCM patients (P < 0.05). RV function was impaired in HCM patients. The RV global strain (RV GLS), and the strain of RV free wall and each segment were lower than those in the normal control group (P < 0.05). Correlation analysis showed that there was a certain correlation between RV myocardial perfusion and strain, such as the β of the whole RV in HCM group had a positive correlation with the strain of the middle segment of the interventricular septum (r = 0.550, P = 0.002).

CONCLUSIONS

The regional myocardial perfusion and strain of the RV in HCM patients are reduced, and there is a positive correlation between them, suggesting that the reduction of myocardial strain may be related to the impairment of myocardial microcirculation.

Strain Assessment in Aortic Stenosis: Pathophysiology and Clinical Utility

Contemporary echocardiographic criteria for grading aortic stenosis severity have remained relatively unchanged, despite significant advances in noninvasive imaging techniques over the last 2 decades. More recently, attention has shifted to the ventricular response to aortic stenosis and how this might be quantified. Global longitudinal strain, semiautomatically calculated from standard two-dimensional echocardiographic images, has been the focus of extensive research. Global longitudinal strain is a sensitive marker of subtle hypertrophy-related impairment in left ventricular function and has shown promise as a relatively robust prognostic marker, both independently and when added to severity classification systems. Herein we review the pathophysiological basis underpinning the potential utility of global longitudinal strain in the assessment of aortic stenosis, as well as its potential role in quantifying myocardial recovery and prognostic discrimination following aortic valve replacement.

Progress in Cardiac Magnetic Resonance Feature Tracking for Evaluating Myocardial Strain in Type-2 Diabetes Mellitus

The global prevalence of type-2 diabetes mellitus (T2DM) has caused harm to human health and economies. Cardiovascular disease is one main cause of T2DM mortality. Increased prevalence of diabetes and associated heart failure (HF) is common in older populations, so accurately evaluating heart-related injury and T2DM risk factors and conducting early intervention are important. Quantitative cardiovascular system imaging assessments, including functional imaging during cardiovascular disease treatment, are also important. The left-ventricular ejection fraction (LVEF) has been traditionally used to monitor cardiac function; it is often preserved or increased in early T2DM, but subclinical heart deformation and dysfunction can occur. Myocardial strains are sensitive to global and regional heart dysfunction in subclinical T2DM. Cardiac magnetic resonance feature-tracking technology (CMR-FT) can visualize and quantify strain and identify subclinical myocardial injury for early management, especially with preserved LVEF. Meanwhile, CMR-FT can be used to evaluate the multiple cardiac chambers involvement mediated by T2DM and the coexistence of complications. This review discusses CMR-FT principles, clinical applications, and research progress in the evaluation of myocardial strain in T2DM.

Early improvement of global longitudinal strain after iron deficiency correction in heart failure with reduced ejection fraction

BACKGROUND

Iron deficiency correction with ferric carboxymaltose improves symptoms and reduces rehospitalization in patients with reduced left ventricular ejection fraction. The mechanisms underlying these improvements are poorly understood. This study aimed to determine changes in left ventricular contractility after iron treatment as reflected in global longitudinal strain.

METHODS

Prospective single-center study including 43 adults with reduced ejection fraction, non-anemic iron deficiency, and functional class II-III heart failure despite optimal medical treatment. Global longitudinal strain through speckle-tracking echocardiography was measured at baseline and 4 weeks after ferric carboxymaltose.

RESULTS

A significant improvement in global longitudinal strain was detected (from -12.3% ± 4.0% at baseline to -15.6% ± 4.1%, p < .001); ferritin and transferrin saturation index had increased, but ejection fraction presented no significant changes (baseline 35.7% ± 4.6%, follow-up 37.2% ± 6.6%, p = .073).

CONCLUSIONS

In patients with heart failure and reduced ejection fraction, the correction of iron deficiency with ferric carboxymaltose is associated with an early improvement in global longitudinal strain, possibly suggesting a direct effect of iron correction on myocardial contractility.

Cardiac function evaluation in children with spinal muscular atrophy: A case-control study

BACKGROUND

Spinal muscular atrophy (SMA) is an autosomal recessive disorder characterized by degeneration of lower motor neurons, resulting in progressive muscle weakness and atrophy. However, little is known regarding the cardiac function of children with SMA.

METHODS

We recruited SMA patients younger than 18 years of age from January 1, 2022, to April 1, 2022, in the First Affiliated Hospital of Sun Yat-sen University. All patients underwent a comprehensive cardiac evaluation before treatment, including history taking, physical examination, blood tests of cardiac biomarkers, assessment of echocardiography and electrocardiogram. Age/gender-matched healthy volunteers were recruited as controls.

RESULTS

A total of 36 SMA patients (26 with SMA type 2 and 10 with SMA type 3) and 40 controls were enrolled in the study. No patient was clinically diagnosed with heart failure. Blood tests showed elevated values of creatine kinase isoenzyme M and isoenzyme B (CK-MB) mass and high-sensitivity cardiac troponin T (hs-cTnT) in spinal muscular atrophy (SMA) patients. Regarding echocardiographic parameters, SMA children were detected with lower global left and right ventricular longitudinal strain, abnormal diastolic filling velocities of trans-mitral and trans-tricuspid flow. The results revealed no clinical heart dysfunction in SMA patients, but subclinical ventricular dysfunction was seen in SMA children including the diastolic function and myocardial performance. Some patients presented with elevated heart rate and abnormal echogenicity of aortic valve or wall. Among these SMA patients, seven patients (19.4%) had scoliosis. The Cobb's angles showed a significant negative correlation with LVEDd/BSA, but no correlation with other parameters, suggesting that mild scoliosis did not lead to significant cardiac dysfunction.

CONCLUSIONS

Our findings warrant increased attention to the cardiac status and highlight the need to investigate cardiac interventions in SMA children.

Effects of sevoflurane on left ventricular function by speckle-tracking echocardiography in coronary bypass patients: A randomized trial

The present study aimed to dynamically observe the segmental and global myocardial movements of the left ventricle during coronary artery bypass grafting by transesophageal speckle-tracking echocardiography, and to assess the effect of sevoflurane on cardiac function. Sixty-four patients scheduled for the off-pump coronary artery bypass grafting were randomly divided into a sevoflurane-based anesthesia (AS) group and a propofol-based total intravenous anesthesia (AA) group. The AS group demonstrated a higher absolute value of left ventricular global longitudinal strain than that of the AA group at both T 1 (after harvesting all grafts and before coronary anastomosis) and T 2 (30 min after completing all coronary anastomoses) ( P < 0.05). Moreover, strain improvement in the segment with the highest preoperative strain was significantly reduced in the AS group, compared with the AA group at both T 1 and T 2 ( P < 0.01). The flow of the left internal mammary artery-left anterior descending artery graft was superior, and the postoperative concentration of troponin T decreased rapidly in the AS group, compared with the AA group ( P < 0.05). Compared with total intravenous anesthesia, sevoflurane resulted in a significantly higher global longitudinal strain, stroke volume, and cardiac output. Sevoflurane also led to an amelioration in the condition of the arterial graft. Furthermore, sevoflurane significantly reduced strain improvement in the segmental myocardium with a high preoperative strain value. The findings need to be replicated in larger studies.

Position Statement on the Use of Myocardial Strain in Cardiology Routines by the Brazilian Society of Cardiology's Department Of Cardiovascular Imaging - 2023

Central Illustration : Position Statement on the Use of Myocardial Strain in Cardiology Routines by the Brazilian Society of Cardiology's Department Of Cardiovascular Imaging - 2023 Proposal for including strain in the integrated diastolic function assessment algorithm, adapted from Nagueh et al.67 Am: mitral A-wave duration; Ap: reverse pulmonary A-wave duration; DD: diastolic dysfunction; LA: left atrium; LASr: LA strain reserve; LVGLS: left ventricular global longitudinal strain; TI: tricuspid insufficiency. Confirm concentric remodeling with LVGLS. In LVEF, mitral E wave deceleration time < 160 ms and pulmonary S-wave < D-wave are also parameters of increased filling pressure. This algorithm does not apply to patients with atrial fibrillation (AF), mitral annulus calcification, > mild mitral valve disease, left bundle branch block, paced rhythm, prosthetic valves, or severe primary pulmonary hypertension.

Global and regional myocardial function assessment in symptomatic patients with chronic coronary syndrome using longitudinal strain and noninvasive myocardial work

Speckle tracking echocardiography (STE) derived longitudinal strain (LS) and noninvasive pressure-strain loop (PSL) derived myocardial work (MW) are more sensitive than conventional echocardiographic parameters in quantitative assessment of early myocardial dysfunction. The aim of this study was to assess left ventricular (LV) global and regional myocardial function in symptomatic chronic coronary syndrome (CCS) patients using the two promising methods. Transthoracic echocardiography was performed on patients with angina or equivalent symptoms before coronary angiography. STE-based LS and PSL-based MW analysis were carried out on each patient for global and regional myocardial function assessment. A total of 102 patients were classified into significant and nonsignificant coronary artery stenosis (CAS) groups. Among global myocardial function parameters, LS had the biggest area under the curve (AUC) of 0.735, with cutoff value of 18.4% (sensitivity, 79.6%; specificity, 72.9%), but remained statistically alike with all MW indices in predicting significant CAS (P>0.05 for all). Among regional myocardial function parameters, both LS and MW indices had predictive value for significant left anterior descending artery (LAD) or left circumflex artery (LCX) stenosis, while only myocardial work efficiency (MWE) for right coronary artery (RCA) stenosis. Both global and regional LS and MW have predictive value for significant CAS, but their value of regionalized assessment varies with specific coronary artery involvement.

Use of speckle tracking echocardiography in evaluating cardiac dysfunction in patients with acromegaly: an update

In recent years, cardiovascular disease has garnered increasing attention as the second leading cause of death in individuals with acromegaly, following malignancy. Identifying cardiac dysfunction early in acromegaly patients for timely intervention has become a focal point of clinical research. Speckle tracking echocardiography, a well-established ultrasound technique, surpasses conventional Doppler ultrasound in its sensitivity to assess both local and global cardiac mechanics. It can accurately detect subclinical and clinical myocardial dysfunction, including myocardial ischemia, ventricular hypertrophy, and valvular changes. Over the past five years, the use of speckle tracking echocardiography in acromegaly patients has emerged as a novel approach. Throughout the cardiac cycle, speckle tracking echocardiography offers a sensitive evaluation of the global and regional myocardial condition by quantifying the motion of myocardial fibres in distinct segments. It achieves this independently of variations in ultrasound angle and distance, effectively simulating the deformation of individual ventricles across different spatial planes. This approach provides a more accurate description of changes in cardiac strain parameters. Importantly, even in the subclinical stage when ejection fraction remains normal, the strain parameters assessed by speckle tracking echocardiography hold a good predictive value for the risk of cardiovascular death and hospitalization in acromegaly patients with concomitant cardiovascular disease. This information aids in determining the optimal timing for interventional therapy, offering important insights for cardiac risk stratification and prognosis. In the present study, we comprehensively reviewed the research progress of speckle tracking echocardiography in evaluating of cardiac dysfunction in acromegaly patients, to pave the way for early diagnosis of acromegaly cardiomyopathy.

Right Ventricular Global Longitudinal Strain and Short-Term Prognosis in Patients With First Acute Myocardial Infarction

Right ventricular (RV) dysfunction after acute myocardial infarction (AMI) is a recognized predictor of dismal prognosis. However, the most reliable RV index to predict mortality early after revascularization remains undetermined. This study aimed to explore the ability of RV global longitudinal strain (GLS) to predict inhospital mortality in patients with first AMI. All consecutive patients with first AMI were prospectively enrolled from March 2022 until February 2023. An echocardiogram was performed 24 hours after successful revascularization and RV GLS alongside conventional echocardiographic indexes were measured. Inhospital mortality was recorded. A total of 300 patients (age 61.2 ± 11.8 years, 74% male) were included in the study. RV GLS was the only RV performance index that differed significantly between anterior and inferior ST-segment-elevation patients with AMI (14.5 ± 5.2% vs 17.4 ± 5.1% respectively, p <0.001). After revascularization, 23 patients (7.7%) died in hospital. The model of Global Registry of Acute Coronary Event risk score and left ventricular ejection fraction, built for predicting inhospital mortality, significantly improved its prognostic performance only by the addition of RV GLS (chi-square value increase by 7.485, p = 0.006) compared with the other RV function indexes. RV GLS was independently associated with inhospital mortality (odds ratio 0.83, 95% confidence interval 0.71 to 0.97, p = 0.017) after adjustment for Global Registry of Acute Coronary Event risk score and left ventricular ejection fraction. Echocardiographic RV GLS measured 24 hours after revascularization in patients with first AMI outperformed conventional RV function indexes in predicting inhospital mortality.

Intraoperative Augmented Rotation and Circumferential Strain Compensate for Reduction of Left Ventricular Longitudinal Function After On-Pump CABG Surgery

OBJECTIVES

Left ventricular (LV) longitudinal function is reduced after on-pump coronary artery bypass grafting (CABG), while global LV function often is preserved. There are only limited data on the underlying compensatory mechanism. Therefore, the authors aimed to describe intraoperative changes of LV contractile pattern by myocardial strain analysis.

DESIGN

A prospective observational study.

SETTING

At a single university hospital.

PARTICIPANTS

A total of 30 patients scheduled for isolated on-pump CABG with an uneventful intraoperative course and preoperative preserved LV and RV function, sinus rhythm, without more-than-mild heart valve disease, or elevated pulmonary pressure.

INTERVENTIONS

Transesophageal echocardiography was performed after induction of anesthesia (T1), after termination of cardiopulmonary bypass (T2), and after sternal closure (T3). Echocardiographic evaluation was performed under stable hemodynamics, in sinus rhythm or atrial pacing, and vasopressor support with norepinephrine ≤0.1 µg/kg/min.

MEASUREMENTS AND MAIN RESULTS

EchoPAC v204 software (GE Vingmed Ultrasound AS, Norway) was used for analysis of 2-dimensional (2D) and 3-dimensional (3D) LV ejection fraction (EF), LV global longitudinal strain (GLS), LV global circumferential strain (GCS), LV global radial strain (GRS), LV apical rotation (aRot), LV basal rotation (bRot), and LV twist. Strain analysis was feasible in all included patients after termination of cardiopulmonary bypass (T2). Although there were no significant differences in the values of conventional echocardiographic parameters during the intraoperative interval, GLS deteriorated significantly after CABG compared to pre-bypass assessment (T1 v T2, -13.4% ± 2.9 v -11.8% ± 2.9; p = 0.007). GCS improved significantly after surgery (T1 v T2, -19.4% (IQR -17.1% to -21.2%) v -22.8% (IQR -21.1% to -24.7%); p < 0.001) as well as aRot (T1 v T2, -9.7° (IQR -7.1° to -14.1°) v -14.5° (IQR -12.1° to -17.1°); p < 0.001), bRot (T1 v T2, 5.1° (IQR 3.8°-6.7°) v 7.2° (IQR 5.6°-8.2°); p = 0.02), and twist (T1 v T2, 15.8° (IQR 11.7°-19.4°) v 21.6° (IQR 19.2°-25.1°); p < 0.001), while GRS remained unchanged. There were no significant changes in the values of GLS, GCS, GRS, aRot, bRot, or twist, as well as in the values of 2D and 3D LV EF before and after sternal closure (T2 v T3).

CONCLUSION

Beyond evaluation of longitudinal LV strain, measurements of circumferential and radial strain, as well as LV rotation and twist mechanics, were feasible in the intraoperative course of this study. Reduction of longitudinal function after on-pump CABG was compensated intraoperatively by improvement of GCS and rotation in the authors' group of patients. Perioperative assessment of GCS, GRS, as well as rotation and twist, might provide deeper insight into perioperative changes of cardiac mechanics.

Effects of septal myectomy on left atrial and left ventricular function in obstructive hypertrophic cardiomyopathy

AIMS

Mechanical function of the left atrium (LA) and the left ventricle (LV) has been demonstrated to be a prognostic factor in patients with hypertrophic cardiomyopathy (HCM). We explore whether myocardial mechanical function can be improved by septal reduction therapy in symptomatic obstructive HCM.

METHODS AND RESULTS

Among 65 patients who underwent septal myectomy for symptomatic obstructive HCM from 2006 to 2022, 44 were analysed after excluding those who underwent simultaneous valve repair or replacement or maze operation. LA and LV functional variables including LA strain and LV global longitudinal strain were evaluated by two-dimensional and speckle-tracking echocardiography and compared before and 1 year after surgery. After septal myectomy, LA volume index (58.1 ± 18.3 vs. 45.3 ± 14.6 mL/m2 , P = 0.001) decreased significantly. As LV end-systolic dimension increased after surgery, the LV ejection fraction decreased (73.8 ± 6.7 vs. 62.9 ± 8.3%, P < 0.001). LA strain (24.4 ± 9.3 vs. 30.5 ± 13.6%, P = 0.004) improved after septal myectomy, but LV global longitudinal strain deteriorated (-12.6 ± 3.6 vs. -11.6 ± 4.3%, P = 0.033), mainly related to worsening non-septal longitudinal strain (-14.4 ± 4.3 vs. -10.9 ± 8.4%, P = 0.005).

CONCLUSIONS

As haemodynamic loads due to LV outflow tract obstruction was relieved through surgical septal reduction therapy in patients with symptomatic obstructive HCM, there was a significant reduction in LA volume and restoration of LA mechanical dysfunction. However, LV mechanical dysfunction deteriorated even after surgical septal reduction therapy.

Left atrial strain superior to structural remodeling in identifying occult atrial fibrillation

OBJECTIVE

Occult atrial fibrillation (AF) is a significant risk factor for occult stroke but is difficult to detect. Myocardial strain, based on speckle tracking echocardiography (STE), can detect subclinical changes in left atrial (LA) function. This study aimed to investigate the diagnostic value of LA strain in identifying asymptomatic AF patients with normal electrocardiograms and healthy volunteers.

METHODS

A total of 354 subjects were retrospectively enrolled. Patients were divided into two groups based on whether they had AF during echocardiography. Patients with sinus rhythm during echocardiography were further divided into healthy control group and occult AF group. Patients with AF during echocardiography were further divided into paroxysmal AF group and persistent AF group. LA mechanical function measured by STE was compared between patients with asymptomatic AF and volunteers. Conventional echocardiographic indicators were measured. The diagnostic value of LA strain for identifying asymptomatic AF was assessed by univariate and multivariate regression analysis and receiver operating characteristic (ROC) curves.

RESULTS

Occult AF patients had higher NT-proBNP levels, larger RA area, larger LAVmax and decreased LAEF than control group. However, occult AF patients had lower NT-proBNP levels, RA area and LAVmax and higher LAEF than paroxysmal and persistent AF. The measured LA reservoir strain (LASr), LA conduit strain (LAScd), LA contraction strain (LASct) of occult AF group was significantly lower than that of control group. However, occult AF patients had preserved LAScd and LASct than paroxysmal and persistent AF. RA area, LAEF and LASr were remarkable correlation with occult AF after adjustment for NT-proBNP, LAVmax, and LAScd. The area under curve of ROC for LASr was the greatest among RA area, LAEF and LASr, with a cut-off value of 34.1% (sensitivity: 75.4%, specificity: 87.6%).

CONCLUSION

LASr can identify occult AF in the asymptomatic population. Patients with LASr values ≤34.1% have a higher incidence of occult cardiac dysfunction. These findings help identify patients with occult AF and further risk stratification for the AF population.

Clinical Usefulness of Speckle-Tracking Echocardiography in Patients with Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is defined as HF with left ventricular ejection fraction (LVEF) not less than 50%. HFpEF accounts for more than 50% of all HF patients, and its prevalence is increasing year to year with the aging population, with its prognosis worsening. The clinical assessment of cardiac function and prognosis in patients with HFpEF remains challenging due to the normal range of LVEF and the nonspecific symptoms and signs. In recent years, new echocardiographic techniques have been continuously developed, particularly speckle-tracking echocardiography (STE), which provides a sensitive and accurate method for the comprehensive assessment of cardiac function and prognosis in patients with HFpEF. Therefore, this article reviewed the clinical utility of STE in patients with HFpEF.

Plasma Serotonin and Cardiovascular Outcomes in Chronic Kidney Disease

Background Platelet-poor plasma serotonin levels are associated with adverse cardiovascular outcomes. Although plasma serotonin levels increase in chronic kidney disease, the cardiovascular implications remain unknown. Methods and Results In 1114 participants from the prospective CRIC (Chronic Renal Insufficiency Cohort) Study, we evaluated the association between plasma serotonin, categorized as undetectable, intermediate, and high (≥20 ng/mL) levels, and cross-sectional findings on echocardiography, including left ventricular hypertrophy, left ventricular ejection fraction, and pulmonary hypertension. We also analyzed whether serotonin was associated with time-to-event cardiovascular outcomes, including heart failure hospitalization and atherosclerotic cardiovascular disease (ASCVD) events, in addition to mortality. Because selective serotonin reuptake inhibitors decrease plasma serotonin levels, we specifically evaluated the influence of selective serotonin reuptake inhibitor use in the relationship between serotonin and outcomes. Plasma serotonin level inversely correlated with estimated glomerular filtration rate and directly correlated with blood pressure. High plasma serotonin was associated with left ventricular hypertrophy (adjusted odds ratio, 2.74 [95% CI, 1.11-7.41]). In contrast, undetectable plasma serotonin level was associated with the highest risk of heart failure (adjusted hazard ratio [HR], 2.26 [95% CI, 1.40-3.66]) and ASCVD events (adjusted HR, 1.96 [95% CI, 1.15-3.32]). Conclusions In a large chronic kidney disease cohort, plasma serotonin levels correlated with blood pressure, and elevated serotonin levels were associated with left ventricular hypertrophy. In contrast, undetectable plasma serotonin was associated with the highest risk of heart failure and ASCVD events.

Early impairment of right ventricular systolic function in patients with prediabetes and type 2 diabetes mellitus: An analysis of two-dimensional speckle tracking echocardiography

BACKGROUND

Type 2 diabetes mellitus is a metabolic disease that affects multiple target organs. Current data on right ventricular damage in type 2 diabetes, especially in prediabetes, are limited. Due to the anatomical characteristics of the right ventricle, the assessment of the right ventricle by conventional echocardiography is difficult, whereas the ultrasound two-dimensional speckle tracking echocardiography can provide information on myocardial systolic function by tracking the motion information of myocardial speckles, which can sensitively reflect myocardial mechanical changes.

AIMS

To assess the effect of prediabetes and diabetes with preserved left ventricular ejection fraction on right ventricular myocardial systolic function and to identify independent risk factors affecting right ventricular systolic function.

METHODS

A total of 49 normoglycaemic (NG) healthy individuals, 43 prediabetics (PDM), and 52 type 2 diabetics (T2DM) were recruited. All study subjects underwent conventional echocardiography and two-dimensional speckle tracking echocardiography (2D-STE).

RESULTS

The right ventricular global longitudinal strain (RVGLS) (20.80 ± 1.96% vs. 18.99 ± 3.20% vs. 16.85 ± 4.01%), left ventricular global longitudinal strain (LVGLS), and interventricular septal longitudinal strain (IVS-LS) (17.28 ± 2. 35% vs. 16.14 ± 3.22% vs. 15.53 ± 3.33%) gradually decreased from the controls, through patients with prediabetes, to those with diabetes (p < .001). Right ventricular free wall strain (RVFW-LS) was higher in the control group (25.63 ± 4.58% vs. 22.83 ± 4.83% vs. 20.79 ± 4.92%) than in the other two groups with a statistically significant difference (p < .001), while RVFW-LS was not statistically different between the prediabetic and diabetic groups. Multivariate regression analysis showed that HbA1c (β = -.626, p < .001), IVS-LS (β = .417, p < .001), and left ventricular end-diastolic diameter (LVEDd) (β = .191, p = .011) were independently correlated with RVGLS.

CONCLUSIONS

Two-dimensional speckle tracking echocardiography can sensitively detect subtle changes in the early impairment of right ventricular systolic function in patients with abnormal glucose metabolism. Type 2 diabetes is the common mechanism causing impaired myocardial mechanics in the right and left ventricles. The reduced global systolic longitudinal strain of the right ventricle was associated with reduced global septal longitudinal strain and left ventricular remodeling. HbA1c is an independent predictor of the global longitudinal strain of the right ventricle, and controlling blood glucose levels may be expected to improve the extent of myocardial damage.

Value of Autostrain LV in the study of left ventricular systolic function and synchronization in patients with systemic lupus erythematosus

BACKGROUND

There are relatively few studies investigating cardiac structural and functional abnormalities associated with systemic lupus erythematous (SLE). The long-term prognosis of SLE patients is closely related to the cardiovascular events caused by SLE. Accordingly, it is necessary to assess early myocardial systolic function and synchrony.

METHODS

Overall, 90 patients with SLE were randomly selected from our outpatient and inpatient clinics and divided according to SLE Disease Activity Index (SLE-DAI-2000) scores: group A, stable (scores 0-4); group B, mildly active stage (scores 5-9); and group C, moderately active stage (scores ≥10). Each group included 30 patients. Further, 30 sex- and age-matched healthy individuals who were referred for check-ups at the same period were selected as controls (group D). The minimum age for entry into the group was 17 years old. Autostrain LV and three-dimensional quantitative analysis (3DQA) were applied to obtain left ventricular systolic function parameters, information on strain parameters, and correlations between parameters. Simultaneity parameters measured by Autostrain LV and 3DQA were tested for reproducibility.

RESULTS

A two-by-two comparison of groups A-C showed that as the disease activity score increased, AP4LS%, AP2LS%, AP3LS%, and the LV mean overall longitudinal strain all gradually decreased, while LV longitudinal strain peak time standard deviation (Tls-SD) gradually increased, with all differences being statistically significant (p < .05). In groups A-C compared with controls, Tmsv-17-SD, Tmsv-17-Dif, Tmsv-17-SD%, and Tmsv-17-Dif% were all significantly prolonged (p < .05). Further, Tls-SD was positively correlated with Tmsv-17-SD and Tmsv-17-Dif, and there was good agreement between Autostrain and 3DQA for the measurement of left ventricular synchrony indexes, with Tmsv-17-Dif having the best repeatability (intraobserver interclass correlation coefficient (ICC) = .979; interobserver ICC = .848, p < .01).

CONCLUSION

Autostrain LV can accurately detect changes in left ventricular myocardial strain in patients with SLE early in the disease, with simple operation. The 3DQA technique can quantitatively evaluate left ventricular systolic synchronization in patients with SLE, and Autostrain LV synchronization index measurements correlate significantly with 3DQA. Both methods are reproducible, but 3DQA is more sensitive to left ventricular synchronous motion changes.

Myocardial strain: a clinical review

BACKGROUND

Myocardial strain-change in myocardial fibre length over the cardiac cycle-is a measure of cardiac muscle function. It is obtained using conventional techniques such as echocardiography and magnetic resonance imaging, adding additional clinical information to augment the current techniques.

METHODS

A narrative review of the current relevant literature with respect to myocardial strain, with a focus on strain measured by echocardiography.

RESULTS

Myocardial strain identifies global and regional abnormalities in myocardial function and differentiates types of cardiomyopathy. It is an earlier marker of myocardial disease than ejection fraction and is predictive of cardiovascular adverse events. Accurate measurement requires high-quality images and experienced practitioners.

CONCLUSION

This review explains advantages and disadvantages of myocardial strain imaging and explains why, through adding increased precision without additional burden, it should be a standard part of cardiac assessment.

Deep Learning for Improved Precision and Reproducibility of Left Ventricular Strain in Echocardiography: A Test-Retest Study

AIMS

Assessment of left ventricular (LV) function by echocardiography is hampered by modest test-retest reproducibility. A novel artificial intelligence (AI) method based on deep learning provides fully automated measurements of LV global longitudinal strain (GLS) and may improve the clinical utility of echocardiography by reducing user-related variability. The aim of this study was to assess within-patient test-retest reproducibility of LV GLS measured by the novel AI method in repeated echocardiograms recorded by different echocardiographers and to compare the results to manual measurements.

METHODS

Two test-retest data sets (n = 40 and n = 32) were obtained at separate centers. Repeated recordings were acquired in immediate succession by 2 different echocardiographers at each center. For each data set, 4 readers measured GLS in both recordings using a semiautomatic method to construct test-retest interreader and intrareader scenarios. Agreement, mean absolute difference, and minimal detectable change (MDC) were compared to analyses by AI. In a subset of 10 patients, beat-to-beat variability in 3 cardiac cycles was assessed by 2 readers and AI.

RESULTS

Test-retest variability was lower with AI compared with interreader scenarios (data set I: MDC = 3.7 vs 5.5, mean absolute difference = 1.4 vs 2.1, respectively; data set II: MDC = 3.9 vs 5.2, mean absolute difference = 1.6 vs 1.9, respectively; all P < .05). There was bias in GLS measurements in 13 of 24 test-retest interreader scenarios (largest bias, 3.2 strain units). In contrast, there was no bias in measurements by AI. Beat-to-beat MDCs were 1,5, 2.1, and 2.3 for AI and the 2 readers, respectively. Processing time for analyses of GLS by the AI method was 7.9 ± 2.8 seconds.

CONCLUSION

A fast AI method for automated measurements of LV GLS reduced test-retest variability and removed bias between readers in both test-retest data sets. By improving the precision and reproducibility, AI may increase the clinical utility of echocardiography.

The non-steroidal mineralocorticoid receptor antagonist finerenone and heart failure with preserved ejection fraction

Finerenone is a novel non-steroidal mineralocorticoid receptor (MR) antagonist (MRA) with high binding affinity, high MR selectivity and a short plasma half-life. In two major endpoint-driven clinical trials in patients with chronic kidney disease and type 2 diabetes mellitus (FIDELIO-DKD and FIGARO-DKD), finerenone induced significant cardiorenal protective actions, and has been recently approved for treatment of these patients. Heart failure with preserved ejection fraction (HFpEF) is a devastating clinical syndrome with increasing prevalence and poor prognosis. Pharmacological therapy of HFpEF is very limited and new therapeutic options are urgently needed. Finerenone has been shown to improve multiple pathophysiological parameters of HFpEF in preclinical models. In consonance, pre-specified subgroup analyses of FIDELIO-DKD and FIGARO-DKD suggested a potential beneficial effect of finerenone in HFpEF. This review will discuss the pharmacodynamic and -kinetic profile of finerenone. We will provide a general overview over the complex pathophysiology of HFpEF and data from pre-clinical studies, focusing on how finerenone improves multiple components of this pathophysiology. Finally, we will discuss current and future clinical trials with finerenone in heart failure patients focusing on HFpEF.

The effect of hyperbaric oxygen therapy on myocardial function in post-COVID-19 syndrome patients: a randomized controlled trial

Post-COVID-19 condition refers to a range of persisting physical, neurocognitive, and neuropsychological symptoms following SARS-CoV-2 infection. Recent evidence revealed that post-COVID-19 syndrome patients may suffer from cardiac dysfunction and are at increased risk for a broad range of cardiovascular disorders. This randomized, sham-control, double-blind trial evaluated the effect of hyperbaric oxygen therapy (HBOT) on the cardiac function of post-COVID-19 patients with ongoing symptoms for at least three months after confirmed infection. Sixty patients were randomized to receive 40 daily HBOT or sham sessions. They underwent echocardiography at baseline and 1-3 weeks after the last protocol session. Twenty-nine (48.3%) patients had reduced global longitudinal strain (GLS) at baseline. Of them, 13 (43.3%) and 16 (53.3%) were allocated to the sham and HBOT groups, respectively. Compared to the sham group, GLS significantly increased following HBOT (- 17.8 ± 1.1 to - 20.2 ± 1.0, p = 0.0001), with a significant group-by-time interaction (p = 0.041). In conclusion, post-COVID-19 syndrome patients despite normal EF often have subclinical left ventricular dysfunction that is characterized by mildly reduced GLS. HBOT promotes left ventricular systolic function recovery in patients suffering from post COVID-19 condition. Further studies are needed to optimize patient selection and evaluate long-term outcomes.This study was registered with ClinicalTrials.gov, number NCT04647656 on 01/12/2020.

Spatial and Temporal Non-Uniform Changes in Left Ventricular Myocardial Strain in Dogs with Duchenne Muscular Dystrophy

BACKGROUND

Understanding and effectively treating dystrophin-deficient cardiomyopathy is of high importance for Duchenne muscular dystrophy (DMD) patients due to their prolonged lifespan. We used two-dimensional speckle tracking echocardiography to analyze more deeply the non-uniformity of myocardial strain within the left ventricle during the progression of cardiomyopathy in golden retriever muscular dystrophy (GRMD) dogs.

METHODS

The circumferential strain (CS) and longitudinal strain (LS) of left ventricular (LV) endocardial, middle and epicardial layers were analyzed from three parasternal short-axis views and three apical views, respectively, in GRMD (n = 22) and healthy control dogs (n = 7) from 2 to 24 months of age.

RESULTS

In GRMD dogs, despite normal global systolic function (normal LV fractional shortening and ejection fraction), a reduction in systolic CS was detected in the three layers of the LV apex but not in the LV middle-chamber and base at 2 months of age. This spatial heterogeneity in CS progressed with age, whereas a decrease in systolic LS could be detected early at 2 months of age in the three layers of the LV wall from three apical views.

CONCLUSIONS

Analyzing the evolution of myocardial CS and LS in GRMD dogs reveals spatial and temporal non-uniform alterations of LV myocardial strain, providing new insights into the progression of dystrophin-deficient cardiomyopathy in this relevant model of DMD.

Machine learning-enhanced echocardiography for screening coronary artery disease

BACKGROUND

Since myocardial work (MW) and left atrial strain are valuable for screening coronary artery disease (CAD), this study aimed to develop a novel CAD screening approach based on machine learning-enhanced echocardiography.

METHODS

This prospective study used data from patients undergoing coronary angiography, in which the novel echocardiography features were extracted by a machine learning algorithm. A total of 818 patients were enrolled and randomly divided into training (80%) and testing (20%) groups. An additional 115 patients were also enrolled in the validation group.

RESULTS

The superior diagnosis model of CAD was optimized using 59 echocardiographic features in a gradient-boosting classifier. This model showed that the value of the receiver operating characteristic area under the curve (AUC) was 0.852 in the test group and 0.834 in the validation group, with high sensitivity (0.952) and low specificity (0.691), suggesting that this model is very sensitive for detecting CAD, but its low specificity may increase the high false-positive rate. We also determined that the false-positive cases were more susceptible to suffering cardiac events than the true-negative cases.

CONCLUSIONS

Machine learning-enhanced echocardiography can improve CAD detection based on the MW and left atrial strain features. Our developed model is valuable for estimating the pre-test probability of CAD and screening CAD patients in clinical practice.

TRIAL REGISTRATION

Registered as NCT03905200 at ClinicalTrials.gov. Registered on 5 April 2019.

Contractile Adaptation of the Left Ventricle Post-myocardial Infarction: Predictions by Rodent-Specific Computational Modeling

Myocardial infarction (MI) results in cardiac myocyte death and the formation of a fibrotic scar in the left ventricular free wall (LVFW). Following an acute MI, LVFW remodeling takes place consisting of several alterations in the structure and properties of cellular and extracellular components with a heterogeneous pattern across the LVFW. The normal function of the heart is strongly influenced by the passive and active biomechanical behavior of the LVFW, and progressive myocardial structural remodeling can have a detrimental effect on both diastolic and systolic functions of the LV leading to heart failure. Despite important advances in understanding LVFW passive remodeling in the setting of MI, heterogeneous remodeling in the LVFW active properties and its relationship to organ-level LV function remain understudied. To address these gaps, we developed high-fidelity finite-element (FE) rodent computational cardiac models (RCCMs) of MI using extensive datasets from MI rat hearts representing the heart remodeling from one-week (1-wk) to four-week (4-wk) post-MI timepoints. The rat-specific models (n = 2 for each timepoint) integrate detailed imaging data of the heart geometry, myocardial fiber architecture, and infarct zone determined using late gadolinium enhancement prior to terminal measurements. The computational models predicted a significantly higher level of active tension in remote myocardium in early post-MI hearts (1-wk post-MI) followed by a return to near the control level in late-stage MI (3- and 4-wk post-MI). The late-stage MI rats showed smaller myofiber ranges in the remote region and in-silico experiments using RCCMs suggested that the smaller fiber helicity is consistent with lower contractile forces needed to meet the measured ejection fractions in late-stage MI. In contrast, in-silico experiments predicted that collagen fiber transmural orientation in the infarct region has little influence on organ-level function. In addition, our MI RCCMs indicated that reduced and potentially positive circumferential strains in the infarct region at end-systole can be used to infer information about the time-varying properties of the infarct region. The detailed description of regional passive and active remodeling patterns can complement and enhance the traditional measures of LV anatomy and function that often lead to a gross and limited assessment of cardiac performance. The translation and implementation of our model in patient-specific organ-level simulations offer to advance the investigation of individualized prognosis and intervention for MI.

Effects of spatial and temporal resolution on cardiovascular magnetic resonance feature tracking measurements using a simple realistic numerical phantom

OBJECTIVES

To develop a single-slice numerical phantom with known myocardial motion, at several temporal and in-plane spatial resolutions, for testing and comparison of Cardiovascular Magnetic Resonance (CMR) feature tracking (FT) software.

METHODS

The phantom was developed based on CMR acquisitions of one volunteer (acquired cine, tagging cine, T1 map, T2 map, proton density weighted image). The numerical MRI simulator JEMRIS was used, and the phantom was generated at several in-plane spatial resolutions (1.4 × 1.4 mm2 to 3.0 × 3.0 mm2) and temporal resolutions (20 to 40 cardiac phases). Two feature tracking software packages were tested: Medical Image Tracking Toolbox (MITT) and two versions of cvi42 (v5.3.8 and v5.13.7). The effect of resolution on strain results was investigated with reference to ground-truth radial and circumferential strain.

RESULTS

Peak radial strain was consistently undermeasured more for cvi42 v5.13.7 than for v5.3.8. Increased pixel size produced a trend of increased difference from ground-truth peak strain, with the largest changes for cvi42 obtained using v5.13.7 between 1.4 × 1.4 mm2 and 3.0 × 3.0 mm2, at 9.17 percentage points (radial) and 8.42 percentage points (circumferential).

CONCLUSIONS

The results corroborate the presence of intervendor differences in feature tracking results and show the magnitude of strain differences between software versions.

ADVANCES IN KNOWLEDGE

This study shows how temporal and in-plane spatial resolution can affect feature tracking with reference to the ground-truth strain of a numerical phantom. Results reaffirm the need for numerical phantom development for the validation and testing of FT software.