Myocardial Postsystolic Shortening and Early Systolic Lengthening: Current Status and Future Directions

Association of postsystolic shortening on stress echocardiography and significant coronary artery stenosis: A single-centre retrospective cohort study

BACKGROUND

Postsystolic shortening (PSS) is one of the proposed quantitative measures to predict myocardial ischaemia in the stress echocardiographic (SE) evaluation. It is previously known that hypo-/akinesia (HA) correlates well with coronary stenosis. However, some patients undergoing SE only present with PSS, and their risk of significant coronary stenosis is less clear. This study aimed to evaluate the association between PSS and significant coronary stenosis compared with HA.

METHODS

This was a retrospective cohort study at the hospital of S:t Görans, Stockholm, Sweden. All patients who underwent SE to investigate inducible ischaemia between 1 January 2018 and 15 October 2021 were eligible for inclusion. Exclusion criteria were normal SE and inconclusive test. Pathological SE were divided into two groups, patients with HA and those with PSS. Outcome was significant coronary artery stenosis visualized by invasive coronary angiography.

RESULTS

The final study population consisted of 108 patients (73 PSS, 35 HA). The presence of HA was associated with a higher risk of significant stenosis compared to those with PSS (63% vs. 23%, p < 0.001). This relationship was observed among males (p < 0.001), but not among females (p = 0.133). Nonsignificant stenosis trended to be more common among patients with PSS (21% vs. 6%, p = 0.053) CONCLUSIONS: The finding of PSS without HA was associated with a lower risk of significant coronary stenosis than HA. However, patients with PSS still often had nonsignificant coronary stenosis and PSS in the evaluation for nonobstructive coronary artery disease (CAD) should be further investigated.

Right Ventricular Function in Arrhythmogenic Right Ventricular Cardiomyopathy: Potential Value of Strain Echocardiography

Arrhythmogenic right ventricular cardiomyopathy is an inherited cardiomyopathy, characterized by abnormal cell adhesions, disrupted intercellular signaling, and fibrofatty replacement of the myocardium. These changes serve as a substrate for ventricular arrhythmias, placing patients at risk of sudden cardiac death, even in the early stages of the disease. Current echocardiographic criteria for diagnosing arrhythmogenic right ventricular cardiomyopathy lack sensitivity, but novel markers of cardiac deformation are not subject to the same technical limitations as current guideline-recommended measures. Measuring cardiac deformation using speckle tracking allows for meticulous quantification of global systolic function, regional function, and dyssynchronous contraction. Consequently, speckle tracking to quantify myocardial strain could potentially be useful in the diagnostic process for the determination of disease progression and to assist risk stratification for ventricular arrhythmias and sudden cardiac death. This narrative review provides an overview of the potential use of different myocardial right ventricular strain measures for characterizing right ventricular dysfunction in arrhythmogenic right ventricular cardiomyopathy and its utility in assessing the risk of ventricular arrhythmias.

Diagnostic potential of myocardial early systolic lengthening for patients with suspected non-ST-segment elevation acute coronary syndrome

BACKGROUND

During early systole, ischemic myocardium with reduced active force experiences early systolic lengthening (ESL). This study aimed to explore the diagnostic potential of myocardial ESL in suspected non-ST-segment elevation acute coronary syndrome (NSTE-ACS) patients with normal wall motion and left ventricular ejection fraction (LVEF).

METHODS

Overall, 195 suspected NSTE-ACS patients with normal wall motion and LVEF, who underwent speckle tracking echocardiography (STE) before coronary angiography, were included in this study. Patients were stratified into the coronary artery disease (CAD) group when there was ≥ 50% stenosis in at least one major coronary artery. The CAD patients were further stratified into the significant (≥ 70% reduction of vessel diameter) stenosis group or the nonsignificant stenosis group. Myocardial strain parameters, including global longitudinal strain (GLS), duration of early systolic lengthening (DESL), early systolic index (ESI), and post-systolic index (PSI), were analyzed using STE and compared between groups. Receiver operating characteristic curve (ROC) analysis was performed to determine the diagnostic accuracy. Logistic regression analysis was conducted to establish the independent and incremental determinants for the presence of significant coronary stenosis.

RESULTS

The DESL and ESI values were higher in patients with CAD than those without CAD. In addition, CAD patients with significant coronary stenosis had higher DESL and ESI than those without significant coronary stenosis. The ROC analysis revealed that ESI was superior to PSI for identifying patients with CAD, and further superior to GLS and PSI for predicting significant coronary stenosis. Moreover, ESI could independently and incrementally predict significant coronary stenosis in patients with CAD.

CONCLUSIONS

The myocardial ESI is of great value for the diagnosis and risk stratification of clinically suspected NSTE-ACS patients with normal LVEF and wall motion.

Systolic myocardial function measured by echocardiographic speckle-tracking and peak oxygen consumption in pediatric childhood cancer survivors-a PACCS study

Background

Cancer therapy-related cardiotoxicity is a major cause of cardiovascular morbidity in childhood cancer survivors. The aims of this study were to investigate systolic myocardial function and its association to cardiorespiratory fitness in pediatric childhood cancer survivors.

Methods

In this sub-study of the international study "Physical Activity and fitness in Childhood Cancer Survivors" (PACCS), echocardiographic measures of left ventricular global longitudinal strain (LV-GLS) and right ventricular longitudinal strain (RV-LS) were measured in 128 childhood cancer survivors aged 9-18 years and in 23 age- and sex-matched controls. Cardiorespiratory fitness was measured as peak oxygen consumption achieved on treadmill and correlated to myocardial function.

Results

Mean LV-GLS was reduced in the childhood cancer survivors compared to the controls, -19.7% [95% confidence interval (CI) -20.1% to -19.3%] vs. -21.3% (95% CI: -22.2% to -20.3%) (p = 0.004), however, mainly within normal range. Only 13% of the childhood cancer survivors had reduced LV longitudinal strain z-score. Mean RV-LS was similar in the childhood cancer survivors and the controls, -23.2% (95% CI: -23.7% to -22.6%) vs. -23.3% (95% CI: -24.6% to -22.0%) (p = 0.8). In the childhood cancer survivors, lower myocardial function was associated with lower peak oxygen consumption [correlation coefficient (r) = -0.3 for LV-GLS]. Higher doses of anthracyclines (r = 0.5 for LV-GLS and 0.2 for RV-LS) and increasing time after treatment (r = 0.3 for LV-GLS and 0.2 for RV-LS) were associated with lower myocardial function.

Conclusions

Left ventricular function, but not right ventricular function, was reduced in pediatric childhood cancer survivors compared to controls, and a lower left ventricular myocardial function was associated with lower peak oxygen consumption. Furthermore, higher anthracycline doses and increasing time after treatment were associated with lower myocardial function, implying that long-term follow-up is important in this population at risk.

A Rare Case of Isolated Right Ventricular Loeffler's Endocarditis in Primary Hypereosinophilic Syndrome

Hypereosinophilic syndrome (HES) is a systemic disorder with various manifestations, characterized by hypereosinophilia and caused by primary or secondary conditions. Loeffler's endocarditis (LE) represents a frequent cardiac manifestation of HES, caused by infiltration of the myocardium by eosinophilic cells, which determines endocardial damage, with subsequent inflammation, thrombosis, and fibrosis of either one or both ventricles. The diagnosis of cardiac involvement is based on a multimodality approach (i.e., two-dimensional transthoracic echocardiography [2D-TTE], speckle-tracking echocardiography [STE], and cardiac magnetic resonance [CMR]), with different findings depending on the stage of disease. STE may be useful in the initial phase when traditional imaging techniques may result negative, whereas CMR allows myocardial tissue characterization along with a better definition of the right ventricle. We present a rare case of LE with isolated right ventricular involvement in a patient with HES caused by chronic eosinophilic leukemia with constitutively activated fusion tyrosine kinase on chromosome 4q12, successfully treated with imatinib mesylate.

Strain Imaging and Ventricular Arrhythmia

Ventricular arrhythmia is one of the main causes of sudden cardiac death. Hence, identifying patients at risk of ventricular arrhythmias and sudden cardiac death is important but can be challenging. The indication for an implantable cardioverter defibrillator as a primary preventive strategy relies on the left ventricular ejection fraction as a measure of systolic function. However, ejection fraction is flawed by technical constraints and is an indirect measure of systolic function. There has, therefore, been an incentive to identify other markers to optimize the risk prediction of malignant arrhythmias to select proper candidates who could benefit from an implantable cardioverter defibrillator. Speckle-tracking echocardiography allows for a detailed assessment of cardiac mechanics, and strain imaging has repeatedly been shown to be a sensitive technique to identify systolic dysfunction unrecognized by ejection fraction. Several strain measures, including global longitudinal strain, regional strain, and mechanical dispersion, have consequently been proposed as potential markers of ventricular arrhythmias. In this review, we will provide an overview of the potential use of different strain measures in the context of ventricular arrhythmias.

Pressure-Strain Loops, a Novel Non-invasive Approach for Assessment of Children with Cardiomyopathy

Non-invasive myocardial work (MW) by left ventricular (LV) pressure-strain loops (PSL) is a novel method for assessing myocardial function while adjusting for afterload, yet pediatric data remain lacking. The aims of this study were to investigate the different patterns of LV PSL and non-invasive MW in pediatric patients with hypertrophic (HCM) and dilated cardiomyopathy (DCM) and their association with exercise tolerance. We included 110 pediatric subjects (mean age, 13 ± 4 years, 35 DCM, 40 HCM, and 35 healthy controls). Standard and speckle-tracking echocardiography were performed. LV PSLs were generated, and global work index (GWI), MW efficiency (GWE), constructive work (GCW), and wasted work (GWW) were compared between groups. Regression analysis was used to assess the influence of ventricular function, dimensions, wall thickness, and wall stress on MW and to predict the association between MW and VO2 max as a surrogate of exercise capacity. Patients with DCM had significantly lower GWI compared to controls (GWI 479.6 ± 263.0 vs 1610.1 ± 211.0, P < 0.005). GWE was significantly reduced in DCM (79.3 ± 7.9 vs 95.2 ± 1.3, P < 0.005) due to significantly reduced GCW and increased GWW. HCM patients had significant reduction in GWI and GWE from normal (1237.7 ± 449.1 vs 1610.1 ± 211.0, P = 0.001 and 89.6 ± 4.9 vs 95.2 ± 1.3, P < 0.005, respectively), although less severe than with DCM. In a multivariate regression analysis, GWE had the highest association with VO2 max in both cohorts (DCM: β = 0.68, P = 0.001, HCM: β = 0.71, P = 0.007). Non-invasively assessed myocardial work and LV PSLs provide novel insights into the mechanisms of dysfunction in pediatric patients with cardiomyopathy with good prediction of clinical status and thus hold promise to further explore myocardial mechanistic with clinical relevance in different disease entities.

Effects of postsystolic shortening and diastolic dyssynchrony on myocardial work in untreated early hypertension patients

OBJECTIVES

Myocardial work is estimated from noninvasive pressure-strain loop for advanced assessment of left ventricular function. Postsystolic shortening and diastolic dyssynchrony of left ventricle were noted early in hypertension. Their novel effects on myocardial work will be illustrated in this study.

METHODS

We recruited 43 newly diagnosed hypertensive patients (mean age 51.3 ± 12.5 years, 55.8% men) and 32 age-matched and sex-matched healthy individuals (mean age 52.7 ± 10.5 years, 37.5% men) as control. Pressure-strain loop derived myocardial work incorporated global longitudinal strain from speckle tracking echocardiography with brachial artery cuff pressure. Postsystolic strain index (PSI) was defined by the percentage of postsystolic shortening over peak strain. Diastolic dyssynchrony was assessed by standard deviation of time to peak early diastolic strain rate (TDSr-SD) of 18 segments, and maximal difference of time to peak early diastolic strain rate (TDSr-MD) between any two segments.

RESULTS

After multivariate regression analysis, global myocardial work index (GWI) was independently correlated with TDSr-SD (B = -0.498, P = 0.001) and TDSr-MD (B = -0.513, P = 0.001). Global myocardial constructive work (GCW) was independently correlated with TDSr-SD (B = -0.334, P = 0.025) and TDSr-MD (B = -0.397, P = 0.007). Global myocardial wasted work (GWW) was independently correlated with PSI (B = 0.358, P = 0.019). Global myocardial work efficiency (GWE) was lower in hypertensive patients than healthy control (P = 0.001). The untreated hypertensive patients were different from the healthy individuals with higher TDSr-SD, TDSr-MD, GWI, GCW, GWW, and PSI (all P < 0.05).

CONCLUSION

In conclusion, the effect of diastolic dyssynchrony mainly influenced constructive work, whereas postsystolic shortening affected wasted work in early untreated hypertension.

Myocardial Work in Patients Hospitalized With COVID-19: Relation to Biomarkers, COVID-19 Severity, and All-Cause Mortality

Background COVID-19 infection has been hypothesized to affect left ventricular function; however, the underlying mechanisms and the association to clinical outcome are not understood. The global work index (GWI) is a novel echocardiographic measure of systolic function that may offer insights on cardiac dysfunction in COVID-19. We hypothesized that GWI was associated with disease severity and all-cause death in patients with COVID-19. Methods and Results In a multicenter study of patients admitted with COVID-19 (n=305), 249 underwent pressure-strain loop analyses to quantify GWI at a median time of 4 days after admission. We examined the association of GWI to cardiac biomarkers (troponin and NT-proBNP [N-terminal pro-B-type natriuretic peptide]), disease severity (oxygen requirement and CRP [C-reactive protein]), and all-cause death. Patients with elevated troponin (n=71) exhibited significantly reduced GWI (1508 versus 1707 mm Hg%; P=0.018). A curvilinear association to NT-proBNP was observed, with increasing NT-proBNP once GWI decreased below 1446 mm Hg%. Moreover, GWI was significantly associated with a higher oxygen requirement (relative increase of 6% per 100-mm Hg% decrease). No association was observed with CRP. Of the 249 patients, 37 died during follow-up (median, 58 days). In multivariable Cox regression, GWI was associated with all-cause death (hazard ratio, 1.08 [95% CI, 1.01-1.15], per 100-mm Hg% decrease), but did not increase C-statistics when added to clinical parameters. Conclusions In patients admitted with COVID-19, our findings indicate that NT-proBNP and troponin may be associated with lower GWI, whereas CRP is not. GWI was independently associated with all-cause death, but did not provide prognostic information beyond readily available clinical parameters. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT04377035.

Correlation Between Glycated Hemoglobin (HbA1c) and Post-Systolic Index Measured by Speckle-Tracking Echocardiography in Patients with Non-apparent Coronary Artery Disease

Glycated hemoglobin (HbA1c) is a useful biomarker for the diagnosis of diabetes and also for determination of individuals with an increased risk of a severe disease. Some subtle changes in myocardial contractile function is measurable by post-systolic index (PSI) which is defined as late systolic shortening after aortic valve closure. The aim of our study was to determine the relationship between HbA1c and PSI in patients with non-apparent coronary artery disease (CAD) on angiograms. This study was a historical cohort study on 85 consecutive patients with a left ventricular ejection fraction ≥ 50% and non-apparent CAD on angiogram. Patients were divided into two groups based on their HbA1c levels, regardless of the diagnosis of diabetes in these patients, to patients with an HbA1c level of equal or higher than 5.7% and those with an HbA1c of less than 5.7%. A speckle-tracking echocardiography was performed for all patients and global longitudinal strain, PSI, left ventricular diameters, left atrial volume, pulsed-Doppler-derived transmitral early (E wave) and late (A wave) diastolic velocities, and tissue-Doppler-derived mitral annular early diastolic (e') and peak systolic (s') velocities were determined. PSI, E/e' ratio, and A wave were higher and e' velocity was lower in patients with HbA1c ≥ 5.7% than those with a level of < 5.7% (P value = 0.04, 0.001, 0.014, and 0.004, respectively). Other echocardiographic variables were not different between two groups. Multiple linear regression analysis showed the association between HbA1c and PSI was independent of other demographic, biochemical, and echocardiographic variables (B = 35.674, 95% CI 10.741-60.606, P value = 0.006). Our study showed PSI is more pronounced in individuals with an HbA1c > 5.7% than those with a lower value in the absence of CAD. Because PSI is an important indicator of adverse outcome and increased mortality, these data can underline the importance of an abnormal HbA1c level and its association with subtle cardiac dysfunction, irrespective of the diagnosis of diabetes in patients with non-apparent CAD.

Normal ranges of non-invasive left ventricular myocardial work indices in healthy young people

OBJECTIVES

Echocardiographic global myocardial work (GMW) indices recently emerged to non-invasively evaluate left ventricular (LV) myocardial performance with less load-dependence than LV ejection fraction (LVEF) or global longitudinal strain (GLS). Yet, few data exist on the descriptions of LV GMW indices in young people. We therefore aimed to provide normal reference values of LV GMW in a healthy young cohort, and simultaneously to investigate factors associated with non-invasive GMW indices.

MATERIALS AND METHODS

A total of 155 healthy young people (age 10-24 years, 59% male) underwent transthoracic echocardiography were recruited and further stratified for age groups and divided by gender. Two-dimensional speckle-tracking echocardiography (2D-STE) were performed to determine LV GLS, peak strain dispersion (PSD) and GMW indices, which include global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE). LV peak systolic pressure was assumed to be equal to the systolic brachial artery cuff blood pressure.

RESULTS

Age and gender specific normal ranges for LV GMW indices were presented. On multivariable analysis, GWI and GCW correlated more closely with systolic blood pressure (SBP) than LV GLS, while both GWW and GWE independently correlated with PSD (P < 0.05 for all). There were no associations between any of the GMW indices with age, sex, body mass index, heart rate, left ventricular mass index as well as LV sizes or LVEF. Of noted, LV GMW indices had good intra-observer and inter-observer reproducibility.

CONCLUSION

We reported echocardiographic reference ranges for non-invasive LV GMW indices in a large group of healthy young subjects, which are reproducible and reliable, and thus can be further used when assessing subclinical dysfunction in young people with myocardial diseases.

Echocardiographic Advances in Dilated Cardiomyopathy

Although the overall survival of patients with dilated cardiomyopathy (DCM) has improved significantly in the last decades, a non-negligible proportion of DCM patients still shows an unfavorable prognosis. DCM patients not only need imaging techniques that are effective in diagnosis, but also suitable for long-term follow-up with frequent re-evaluations. The exponential growth of echocardiography’s technology and performance in recent years has resulted in improved diagnostic accuracy, stratification, management and follow-up of patients with DCM. This review summarizes some new developments in echocardiography and their promising applications in DCM. Although nowadays cardiac magnetic resonance (CMR) remains the gold standard technique in DCM, the echocardiographic advances and novelties proposed in the manuscript, if properly integrated into clinical practice, could bring echocardiography closer to CMR in terms of accuracy and may certify ultrasound as the technique of choice in the follow-up of DCM patients. The application in DCM patients of novel echocardiographic techniques represents an interesting emergent research area for scholars in the near future.