Risk assessment of ventricular arrhythmias in patients with nonischemic dilated cardiomyopathy by strain echocardiography

Myocardial Strain Imaging: Theory, Current Practice, and the Future

Myocardial strain imaging by echocardiography or cardiac magnetic resonance (CMR) is a powerful method to diagnose cardiac disease. Strain imaging provides measures of myocardial shortening, thickening, and lengthening and can be applied to any cardiac chamber. Left ventricular (LV) global longitudinal strain by speckle-tracking echocardiography is the most widely used clinical strain parameter. Several CMR-based modalities are available and are ready to be implemented clinically. Clinical applications of strain include global longitudinal strain as a more sensitive method than ejection fraction for diagnosing mild systolic dysfunction. This applies to patients suspected of having heart failure with normal LV ejection fraction, to early systolic dysfunction in valvular disease, and when monitoring myocardial function during cancer chemotherapy. Segmental LV strain maps provide diagnostic clues in specific cardiomyopathies, when evaluating LV dyssynchrony and ischemic dysfunction. Strain imaging is a promising modality to quantify right ventricular function. Left atrial strain may be used to evaluate LV diastolic function and filling pressure.

Arrhythmic Risk Stratification and Sudden Cardiac Death Prevention in Duchenne Muscular Dystrophy: A Critical Appraisal

Duchenne muscular dystrophy (DMD) is a genetic progressive neuromuscular disorder characterized by early-onset proximal muscle weakness and significant long-term pulmonary and cardiac involvement. Due to the early pharmacological treatments and the wider adoption of non-invasive ventilation, life expectancy has significantly increased in recent years, highlighting the relevance of DMD-related cardiomyopathy and fatal arrhythmias, especially in the late stage of the disease. Current guideline-derived evaluation of sudden cardiac death (SCD) in DMD lacks accuracy, leading to inadequate arrhythmic risk stratification and jeopardized SCD prevention strategies. This review aims to outline these critical issues, proposing an integrative approach encompassing manifold tools such as an imaging-derived systematic and comprehensive evaluation (speckle-tracking echocardiography and magnetic resonance imaging), the electrophysiological study, the 3-dimensional electroanatomic mapping, and a multidimensional clinical examination. This approach might lead to more personalized management along with an effective arrhythmia-prevention strategy aiming to balance clinical care goals, patient expectations, and ethical considerations.

Critical approach to the 2023 European Society of Cardiology guidelines on cardiomyopathies: a document by the Working Group on Myocardial and Pericardial Diseases of the Italian Society of Cardiology

Last year, the European Society of Cardiology (ESC) published the first guidelines to comprehensively address the management of cardiomyopathies. This document by the Working Group on Myocardial and Pericardial Diseases of the Italian Society of Cardiology aims at highlighting the most relevant messages and novelties introduced by these guidelines for the management of patients affected by cardiomyopathies. Five main messages are summarized: the key role of the phenotype, the new classification of cardiomyopathies provided in the ESC guidelines, the importance given to new techniques such as cardiac magnetic resonance (CMR) and genetic testing, the newly provided recommendations given on sport activities and finally how the importance of follow-up evaluations is highlighted. These five main messages are then further analyzed more in depth so as to inform the reader on all the main novelties of the guidelines and to provide a critical approach to this important document.

Left atrial mechanical dispersion and left atrial stiffness predicts recurrence of atrial fibrillation: In patients with moderate-severe rheumatic mitral stenosis

AIMS

The aim of this study was to evaluate the relationship between preoperative left atrial function and recurrence of atrial fibrillation (AF) after mitral valve surgery and Cox Maze procedure in patients with moderate-to-severe rheumatic mitral stenosis (MS) combined with AF, in order to facilitate clinical risk stratification and to guide treatment strategies.

METHODS AND RESULTS

Patients with moderate-to-severe rheumatic MS attending Beijing Anzhen Hospital of Capital Medical University from April 2022 to September 2023 were prospectively collected, and all of them underwent transthoracic two-dimensional speckle-tracking echocardiography to assess left atrial structure and function before undergoing mitral valve surgery and Cox Maze procedure and postoperative follow-up. 121 patients were enrolled, of whom 77.69 % (94/121) were female, with a median follow-up time of 9.56 ± 1.83 months, and 48 patients (39.7 %, 48/121) had postoperative recurrence of AF. Preoperative left atrial stiffness index (LASI) [3.76(3.10-5.44) vs. 2.41(1.75-3.33), P < 0.001] and left atrial mechanical dispersion (SD-TPS) (15.84 ± 5.92vs. 11.58 ± 5.96, P = 0.001) were significantly higher in the postoperative AF recurrence group than in the without recurrence group; Multivariable cox regression analysis showed that LASI>3.15 and SD -TPS > 13.2 were associated with independent risk factors for AF recurrence (hazard ratio = 2.957, 95 %CI,1.366-6.399, P = 0.006 and hazard ratio = 2.892, 95 %CI,1.381-6.057, P = 0.005).

CONCLUSION

LASI and SD-TPS were effective predictors of postoperative recurrence of AF in patients with moderate-to-severe rheumatic MS, and LASI >3.15 and SD-TPS% >13.2 were independent influences on the recurrence of AF after Cox Maze in this group of patients.

Prognostic Value of Speckle Tracking Echocardiography-Derived Strain in Unmasking Risk for Arrhythmias in Children with Myocarditis

Background/Objectives: Risk assessment in pediatric myocarditis is challenging, particularly when left ventricular ejection fraction (LVEF) is preserved. This study aimed to evaluate LV myocardial deformation using speckle-tracking echocardiography (STE)-derived longitudinal +strain (LS) and assessed its diagnostic and prognostic value in children with myocarditis. Methods: Retrospective STE-derived layer-specific LV LS analysis was performed on echocardiograms from patients within the multicenter, prospective registry for pediatric myocarditis "MYKKE". Age- and sex-adjusted logistic regression and ROC analysis identified predictors of cardiac arrhythmias (ventricular tachycardia, ventricular fibrillation, atrioventricular blockage III°) and major adverse cardiac events (MACE: need for mechanical circulatory support (MCS), cardiac transplantation, and/or cardiac death). Results: Echocardiograms from 175 patients (median age 15 years, IQR 7.9-16.5 years; 70% male) across 13 centers were included. Cardiac arrhythmias occurred in 36 patients (21%), and MACE in 28 patients (16%). Impaired LV LS strongly correlated with reduced LVEF (r > 0.8). Impaired layer-specific LV LS, reduced LVEF, LV dilatation, and increased BSA-indexed LV mass, were associated with the occurrence of MACE and cardiac arrhythmias. In patients with preserved LVEF, LV LS alone predicted cardiac arrhythmias (p < 0.001), with optimal cutoff values of -18.0% for endocardial LV LS (sensitivity 0.69, specificity 0.94) and -17.0% for midmyocardial LV LS (sensitivity 0.81, specificity 0.75). Conclusions: In pediatric myocarditis, STE-derived LV LS is not only a valuable tool for assessing systolic myocardial dysfunction and predicting MACE but also identifies patients at risk for cardiac arrhythmias, even in the context of preserved LVEF.

The Uncertain Benefit from Implantable Cardioverter-Defibrillators in Nonischemic Cardiomyopathy: How to Guide Clinical Decision-Making?

Life-threatening dysrhythmias remain a significant cause of mortality in patients with nonischemic cardiomyopathy (NICM). Implantable cardioverter-defibrillators (ICD) effectively reduce mortality in patients who have survived a life-threatening arrhythmic event. The evidence for survival benefit of primary prevention ICD for patients with high-risk NICM on guideline-directed medical therapy is not as robust, with efficacy questioned by recent studies. In this review, we summarize the data on the risk of life-threatening arrhythmias in NICM, the recommendations, and the evidence supporting the efficacy of primary prevention ICD, and highlight tools that may improve the identification of patients who could benefit from primary prevention ICD implantation.

Risk Assessment and Personalized Treatment Options in Inherited Dilated Cardiomyopathies: A Narrative Review

Considering the worldwide impact of heart failure, it is crucial to develop approaches that can help us comprehend its root cause and make accurate predictions about its outcome. This is essential for lowering the suffering and death rates connected with this widespread illness. Cardiomyopathies frequently result from genetic factors, and the study of heart failure genetics is advancing quickly. Dilated cardiomyopathy (DCM) is the most prevalent kind of cardiomyopathy, encompassing both genetic and nongenetic abnormalities. It is distinguished by the enlargement of the left ventricle or both ventricles, accompanied by reduced contractility. The discovery of the molecular origins and subsequent awareness of the molecular mechanism is broadening our knowledge of DCM development. Additionally, it emphasizes the complicated nature of DCM and the necessity to formulate several different strategies to address the diverse underlying factors contributing to this disease. Genetic variants that can be transmitted from one generation to another can be a significant contributor to causing family or sporadic hereditary DCM. Genetic variants also play a significant role in determining susceptibility for acquired triggers for DCM. The genetic causes of DCM can have a large range of phenotypic expressions. It is crucial to select patients who are most probable to gain advantages from genetic testing. The purpose of this research is to emphasize the significance of identifying genetic DCM, the relationships between genotype and phenotype, risk assessment, and personalized therapy for both those affected and their relatives. This approach is expected to gain importance once treatment is guided by genotype-specific advice and disease-modifying medications.

Deep Learning-Derived Myocardial Strain

BACKGROUND

Echocardiographic strain measurements require extensive operator experience and have significant intervendor variability. Creating an automated, open-source, vendor-agnostic method to retrospectively measure global longitudinal strain (GLS) from standard echocardiography B-mode images would greatly improve post hoc research applications and may streamline patient analyses.

OBJECTIVES

This study was seeking to develop an automated deep learning strain (DLS) analysis pipeline and validate its performance across multiple applications and populations.

METHODS

Interobserver/-vendor variation of traditional GLS, and simulated effects of variation in contour on speckle-tracking measurements were assessed. The DLS pipeline was designed to take semantic segmentation results from EchoNet-Dynamic and derive longitudinal strain by calculating change in the length of the left ventricular endocardial contour. DLS was evaluated for agreement with GLS on a large external dataset and applied across a range of conditions that result in cardiac hypertrophy.

RESULTS

In patients scanned by 2 sonographers using 2 vendors, GLS had an intraclass correlation of 0.29 (95% CI: -0.01 to 0.53, P = 0.03) between vendor measurements and 0.63 (95% CI: 0.48-0.74, P < 0.001) between sonographers. With minor changes in initial input contour, step-wise pixel shifts resulted in a mean absolute error of 3.48% and proportional strain difference of 13.52% by a 6-pixel shift. In external validation, DLS maintained moderate agreement with 2-dimensional GLS (intraclass correlation coefficient [ICC]: 0.56, P = 0.002) with a bias of -3.31% (limits of agreement: -11.65% to 5.02%). The DLS method showed differences (P < 0.0001) between populations with cardiac hypertrophy and had moderate agreement in a patient population of advanced cardiac amyloidosis: ICC was 0.64 (95% CI: 0.53-0.72), P < 0.001, with a bias of 0.57%, limits of agreement of -4.87% to 6.01% vs 2-dimensional GLS.

CONCLUSIONS

The open-source DLS provides lower variation than human measurements and similar quantitative results. The method is rapid, consistent, vendor-agnostic, publicly released, and applicable across a wide range of imaging qualities.

Blood volume contributes to the mechanical synchrony of the myocardium during moderate and high intensity exercise in women

PURPOSE

Whether blood volume (BV) primarily determines the synchronous nature of the myocardium remains unknown. This study determined the impact of standard blood withdrawal on left ventricular mechanical dyssynchrony (LVMD) in women.

METHODS

Transthoracic speckle-tracking echocardiography and central hemodynamic measurements were performed at rest and during moderate- to high-intensity exercise in healthy women (n = 24, age = 53.6 ± 16.3 year). LVMD was determined via the time to peak standard deviation (TPSD) of longitudinal and transverse strain and strain rates (LSR, TSR). Measurements were repeated within a week period immediately after a 10% reduction of BV.

RESULTS

With intact BV, all individuals presented cardiac structure and function variables within normative values of the study population. Blood withdrawal decreased BV (5.3 ± 0.7 L) by 0.5 ± 0.1 L. Resting left ventricular (LV) end-diastolic volume (- 8%, P = 0.040) and passive filling (- 16%, P = 0.001) were reduced after blood withdrawal. No effect of blood withdrawal was observed for any measure of LVMD at rest (P ≥ 0.225). During exercise at a fixed submaximal workload (100 W), LVMD of myocardial longitudinal strain (LS TPSD) was increased after blood withdrawal (36%, P = 0.047). At peak effort, blood withdrawal led to increased LVMD of myocardial transverse strain rate (TSR TPSD) (31%, P = 0.002). The effect of blood withdrawal on TSR TPSD at peak effort was associated with LV concentric remodeling (r = 0.59, P = 0.003).

CONCLUSION

Marked impairments in the mechanical synchrony of the myocardium are elicited by moderate blood withdrawal in healthy women during moderate and high intensity exercise.

Assessing heterogeneity on cardiovascular magnetic resonance imaging: a novel approach to diagnosis and risk stratification in cardiac diseases

Cardiac disease affects the heart non-uniformly. Examples include focal septal or apical hypertrophy with reduced strain in hypertrophic cardiomyopathy, replacement fibrosis with akinesia in an infarct-related coronary artery territory, and a pattern of scarring in dilated cardiomyopathy. The detail and versatility of cardiovascular magnetic resonance (CMR) imaging mean it contains a wealth of information imperceptible to the naked eye and not captured by standard global measures. CMR-derived heterogeneity biomarkers could facilitate early diagnosis, better risk stratification, and a more comprehensive prediction of treatment response. Small cohort and case-control studies demonstrate the feasibility of proof-of-concept structural and functional heterogeneity measures. Detailed radiomic analyses of different CMR sequences using open-source software delineate unique voxel patterns as hallmarks of histopathological changes. Meanwhile, measures of dispersion applied to emerging CMR strain sequences describe variable longitudinal, circumferential, and radial function across the myocardium. Two of the most promising heterogeneity measures are the mean absolute deviation of regional standard deviations on native T1 and T2 and the standard deviation of time to maximum regional radial wall motion, termed the tissue synchronization index in a 16-segment left ventricle model. Real-world limitations include the non-standardization of CMR imaging protocols across different centres and the testing of large numbers of radiomic features in small, inadequately powered patient samples. We, therefore, propose a three-step roadmap to benchmark novel heterogeneity biomarkers, including defining normal reference ranges, statistical modelling against diagnosis and outcomes in large epidemiological studies, and finally, comprehensive internal and external validations.

Additive Prognostic Value of Left Ventricular Dispersion and Deformation in Patients With Severe Aortic Stenosis

BACKGROUND

Speckle tracking strain echocardiography allows one to visualize the timing of maximum regional strain and quantifies left ventricular-mechanical dispersion (LV-MD). Whether LV-MD and LV-global longitudinal strain (LV-GLS) provide similar or complementary information in mortality risk stratification in patients with severe aortic stenosis (SAS) remains unknown.

OBJECTIVES

The authors hypothesized that LV mechanical dyssynchrony assessed by LV-MD is associated with an increased risk of mortality and provides additional prognostic information on top of LV-GLS in patients with SAS.

METHODS

A total of 364 patients with SAS (aortic valve area indexed ≤0.6 cm2/m2 and/or aortic valve area ≤1 cm2), LV ejection fraction ≥50% and no or mild symptoms were enrolled. The endpoint was overall mortality.

RESULTS

During a median follow-up period of 41 months, 149 patients died. After adjustment, LV-MD ≥68 ms was significantly associated with an increased risk of mortality (adjusted HR: 1.41; 95% CI: 1.01-1.96; P = 0.044). Adding LV-MD ≥68 ms to a multivariable Cox regression model including LV-GLS ≥-15% improved predictive performance in terms of overall mortality, with improved global model fit, reclassification, and better discrimination. Patients with both criteria had an important increase in mortality compared to patients with none or one criterion (adjusted HR: 2.02; 95% CI: 1.34-3.03; P = 0.001). Interobserver reproducibility of LV-MD was good with an intraclass correlation coefficient of 0.90 (95% CI: 0.72-0.97).

CONCLUSIONS

LV-MD is a reproducible parameter independently associated with an increased risk of mortality in SAS. Increased LV-MD associated with depressed LV-GLS identifies a subgroup of patients with an increased mortality risk. Whether early aortic valve replacement improves the outcome of these patients deserves further studies.

Multidisciplinary approach in cardiomyopathies: From genetics to advanced imaging

Cardiomyopathies are myocardial diseases characterized by mechanical and electrical dysfunction of the heart muscle which could lead to heart failure and life-threatening arrhythmias. Certainly, an accurate anamnesis, a meticulous physical examination, and an ECG are cornerstones in raising the diagnostic suspicion. However, cardiovascular imaging techniques are indispensable to diagnose a specific cardiomyopathy, to stratify the risk related to the disease and even to track the response to the therapy. Echocardiography is often the first exam that the patient undergoes, because of its non-invasiveness, wide availability, and cost-effectiveness. Cardiac magnetic resonance imaging allows to integrate and implement the information obtained with the echography. Furthermore, cardiomyopathies' genetic basis has been investigated over the years and the list of genetic mutations deemed potentially pathogenic is expected to grow further. The aim of this review is to show echocardiographic, cardiac magnetic resonance imaging, and genetic features of several cardiomyopathies: dilated cardiomyopathy (DMC), hypertrophic cardiomyopathy (HCM), arrhythmogenic cardiomyopathy (ACM), left ventricular noncompaction cardiomyopathy (LVNC), myocarditis, and takotsubo cardiomyopathy.

Multimodal Cardiac Imaging in the Assessment of Patients Who Have Suffered a Cardioembolic Stroke: A Review

Cardioembolic strokes account for 20-25% of all ischaemic strokes, with their incidence increasing with age. Cardiac imaging plays a crucial role in identifying cardioembolic causes of stroke, with early and accurate identification affecting treatment, preventing recurrence, and reducing stroke incidence. Echocardiography serves as the mainstay of cardiac evaluation. Transthoracic echocardiography (TTE) is the first line in the basic evaluation of structural heart disorders, valvular disease, vegetations, and intraventricular thrombus. It can be used to measure chamber size and systolic/diastolic function. Trans-oesophageal echocardiography (TOE) yields better results in identifying potential cardioembolic sources of stroke and should be strongly considered, especially if TTE does not yield adequate results. Cardiac computed tomography and cardiac magnetic resonance imaging provide better soft tissue characterisation, high-grade anatomical information, spatial and temporal visualisation, and image reconstruction in multiple planes, especially with contrast. These techniques are useful in cases of inconclusive echocardiograms and can be used to detect and characterise valvular lesions, thrombi, fibrosis, cardiomyopathies, and aortic plaques. Nuclear imaging is not routinely used, but it can be used to assess left-ventricular perfusion, function, and dimensions and may be useful in cases of infective endocarditis. Its use should be considered on a case-by-case basis. The accuracy of each imaging modality depends on the likely source of cardioembolism, and the choice of imaging approach should be tailored to individual patients.

Usefulness of post-systolic index in facilitating stratification of risk in patients with intermediate- or low-risk non-ST-segment elevation acute coronary syndrome

BACKGROUND

Although there is reportedly a usefulness of left ventricular global longitudinal strain (LV GLS) on 2D speckle-tracking echocardiography in excluding significant coronary artery disease (CAD) in suspected intermediate- or low-risk non-ST-segment elevation-acute coronary syndrome (NSTE-ACS), the efficacy of post-systolic index (PSI) in this context is yet unknown. Therefore, we explored the usefulness of PSI in facilitating stratification of risk in patients with intermediate- or low-risk NSTE-ACS.

METHODS AND RESULTS

We assessed 50 consecutive patients suspected of intermediate- or low-risk NSTE-ACS, and finally analyzed 43 patients whose echocardiographic images were suitable for strain analysis. All patients underwent CAG. Among the 43 analyzed patients, 26 had CAD, and 21 underwent percutaneous coronary intervention (PCI). Patients with CAD had higher PSI (25% [20.8-40.3%] vs 15% [8.0-27.5%], P = 0.007). Receiver-operator characteristic curve analysis identified that a PSI of > 20% detected performance of PCI (sensitivity 80.7%, specificity 70.6%, area under curve [AUC] 0.72, 95% confidence interval [CI] 0.57-0.88). Moreover, the AUC obtained using the GRACE risk score was 0.57 (95% CI 0.39-0.75), and increased to 0.75 (95% CI 0.60-0.90) when PSI and LV GLS were added. Thus, the addition of PSI and LV GLS improved the classification of performance of PCI (net reclassification improvement [95%CI] 0.09 [0.0024-0.18], P = 0.04).

CONCLUSIONS

Post-systolic index is a useful parameter that can facilitate stratification of risk in patients with intermediate- or low-risk NSTE-ACS. We recommend measuring PSI in routine clinical practice.

The Uncertain Benefit from Implantable Cardioverter-Defibrillators in Nonischemic Cardiomyopathy: How to Guide Clinical Decision-Making?

Life-threatening dysrhythmias remain a significant cause of mortality in patients with nonischemic cardiomyopathy (NICM). Implantable cardioverter-defibrillators (ICD) effectively reduce mortality in patients who have survived a life-threatening arrhythmic event. The evidence for survival benefit of primary prevention ICD for patients with high-risk NICM on guideline-directed medical therapy is not as robust, with efficacy questioned by recent studies. In this review, we summarize the data on the risk of life-threatening arrhythmias in NICM, the recommendations, and the evidence supporting the efficacy of primary prevention ICD, and highlight tools that may improve the identification of patients who could benefit from primary prevention ICD implantation.

Cardiac imaging for the prediction of sudden cardiac arrest in patients with heart failure

The identification of heart failure (HF) patients at risk for arrhythmic sudden cardiac arrest (SCA) is a major challenge in the cardiovascular field. In addition to optimal medical treatment for HF, implantable cardioverter defibrillator (ICD) is currently recommended to prevent SCA in patients with reduced left ventricular ejection fraction (LVEF). The indication for an ICD implantation, in addition to HF etiology, New York Health Association (NYHA) class and life expectancy, mainly depends on LVEF value at echocardiography. However, the actual role of LVEF in the prediction of SCA has recently been debated, while newer multimodality imaging techniques with increased prognostic accuracy have been developed. Speckle tracking imaging allows the quantification of mechanical dispersion, a marker of electrophysiological heterogeneity predisposing to malignant arrhythmias, while advanced cardiac magnetic resonance techniques such as myocardial T1-mapping and extracellular volume fraction assessment allow the evaluation of interstitial diffuse fibrosis. Nuclear imaging is helpful for the appraisal of sympathetic nervous system dysfunction, while newer computed tomography techniques assessing myocardial delayed enhancement allow the identification of focal myocardial scar. This review will focus on the most modern advances in the field of cardiovascular imaging along with its applications for the prediction of SCA in patients with HF. Modern artificial intelligence applications in cardiovascular imaging will also be discussed.

Mechanical Dispersion Discriminates between Arrhythmic and Non-Arrhythmic Sudden Death: From the POST SCD Study

Background

Global longitudinal strain (GLS) and mechanical dispersion (MD) by speckle-tracking echocardiography can predict sudden cardiac death (SCD) beyond left ventricular ejection fraction (LVEF) alone. However, prior studies have presumed cardiac cause from EMS records or death certificates rather than gold-standard autopsies.

Objectives

We sought to investigate whether abnormal GLS and MD, reflective of underlying myocardial fibrosis, are associated with autopsy-defined sudden arrhythmic death (SAD) in a comprehensive postmortem study.

Methods

We identified and autopsied all World Health Organization-defined (presumed) SCDs ages 18-90 via active surveillance of out of hospital deaths in the ongoing San Francisco POstmortem Systematic InvesTigation of Sudden Cardiac Death (POST SCD) Study to refine presumed SCDs to true cardiac causes. We retrieved all available pre-mortem echocardiograms and assessed LVEF, LV-GLS, and MD. The extent of LV myocardial fibrosis was assessed and quantified histologically.

Results

Of 652 autopsied subjects, 65 (10%) had echocardiograms available for primary review, obtained at a mean 1.5 years before SCD. Of these, 37 (56%) were SADs and 29 (44%) were non-SADs; fibrosis was quantified in 38 (58%). SADs were predominantly male, but had similar age, race, baseline comorbidities, and LVEF compared to non-SADs (all p>0.05). SADs had significantly reduced LV-GLS (median: -11.4% versus -18.5%, p=0.008) and increased MD (median: 14.8 ms versus 9.4 ms, p=0.006) compared to non-SADs. MD was associated with total LV fibrosis by linear regression in SADs (r=0.58, p=0.002).

Conclusion

In this countywide postmortem study of all sudden deaths, autopsy-confirmed arrhythmic deaths had significantly lower LV-GLS and increased MD than non-arrhythmic sudden deaths. Increased MD correlated with higher histologic levels of LV fibrosis in SADs. These findings suggest that increased MD, which is a surrogate for the extent of myocardial fibrosis, may improve risk stratification and specification for SAD beyond LVEF.

PERSPECTIVES

Competency in medical knowledge: Mechanical dispersion derived from speckle tracking echocardiography provides better discrimination between autopsy-defined arrhythmic vs non-arrhythmic sudden death than LVEF or LV-GLS. Histological ventricular fibrosis correlates with increased mechanical dispersion in SAD.Translational outlook: Speckle tracking echocardiography parameters, in particular mechanical dispersion, may be considered as a non-invasive surrogate marker for myocardial fibrosis and risk stratification in SCD.

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.

Myocardial bridge and beta blockers: effect on left ventricular strain parameters

OBJECTIVES

To assess the effect of beta-blocker treatment on left ventricular global longitudinal strain (LV Gls) as measured by echocardiography in patients with MB (Myocardial Bridge).

PATIENTS AND METHODS

Between January 2019 and February 2022, a prospective, single-center study was undertaken in which myocardial bridging was identified in individuals who had coronary angiography. One hundred patients with myocardial bridging were systematically recruited and strain echocardiography was performed. Patient data were analysed in two groups - those who weren't using beta-blockers in the last six months (Group I: n = 50) vs. those who were (Group II: n = 50).

RESULTS

One hundred patients participated in the study (38 females, 62 males; average age: 57.4 years). There was a statistically significant difference in the mean heart rate between groups I and II (p < 0.001). LV Gls was found to be statistically significantly improved in favour of group II when compared to group I [Group I: (-12.57)±3 vs. Group II: (-15.92)±2.9, p < 0.001].

CONCLUSION

The negative chronotropic effect of beta-blocker medication in individuals with MB identified by coronary angiography has a beneficial effect on LV Gls as measured by echocardiography.

Reduced inferior wall longitudinal strain is associated with malignant arrhythmias in non-ischemic heart failure

BACKGROUND

Reduced systolic myocardial function in the inferior region of the left ventricle has been suggested to be associated with malignant arrhythmias. We tested this hypothesis in patients with non-ischemic heart failure.

METHODS

Patients with non-ischemic heart failure (left ventricular ejection fraction [LVEF] < 35%) were evaluated by 2D-speckle-tracking echocardiography. The regional longitudinal strain was calculated for each of the six left ventricular walls. The reduced regional function was defined as strain below the median. The outcome was a composite of sudden cardiac death, admission with sustained ventricular arrhythmia, resuscitated cardiac arrest, and appropriate therapy from a primary prophylactic implantable cardioverter defibrillator. Time-to-first-event analysis was performed using a Cox model.

RESULTS

From two centers, 401 patients were included (median age: 63 years, 72% male) with a median LVEF of 25% (interquartile range [IQR] 20;30), and a median inferior wall strain of -9.0% (-12.5; -5.4). During a median follow-up of 4.0 years, 52 outcomes occurred. After multivariate adjustment for clinical and electrocardiographic parameters, inferior wall strain was independently associated with the outcome (HR 2.50 [1.35; 4.62], p = .003). No independent association was found between the composite outcome and reduced strain in any of the other left ventricular walls, Global Longitudinal Strain (HR 1.66 [0.93; 2.98], p = .09), or LVEF (HR 1.33 [0.75; 2.33], p = .33).

CONCLUSIONS

Below median strain in the left ventricular inferior region was independently associated with a 2.5-fold increase in the risk of malignant arrhythmias and sudden cardiac death in patients with non-ischemic heart failure.

Cardiometabolic Care: Assessing Patients with Diabetes Mellitus with No Overt Cardiovascular Disease in the Light of Heart Failure Development Risk

The mechanisms leading to the development of heart failure (HF) in diabetes mellitus (DM) patients are multifactorial. Assessing the risk of HF development in patients with DM is valuable not only for the identification of a high-risk subgroup, but also equally important for defining low-risk subpopulations. Nowadays, DM and HF have been recognized as sharing similar metabolic pathways. Moreover, the clinical manifestation of HF can be independent of LVEF classification. Consequently, approaching HF should be through structural, hemodynamic and functional evaluation. Thus, both imaging parameters and biomarkers are important tools for the recognition of diabetic patients at risk of HF manifestation and HF phenotypes, and arrhythmogenic risk, and eventually for prognosis, aiming to improve patients' outcomes utilizing drugs and non-pharmaceutical cardioprotective tools such as diet modification.

Acute and Chronic Changes in Myocardial Work Parameters in Patients with Severe Primary Mitral Regurgitation Undergoing Transcatheter Edge-to-Edge Repair

BACKGROUND

The noninvasive assessment of myocardial work (MW) allows for the evaluation of left ventricular (LV) performance by considering the effect of LV afterload. This study aims to evaluate the acute and chronic impact of transcatheter edge-to-edge repair (TEER) on MW parameters and LV remodeling in patients with severe primary mitral regurgitation (PMR).

METHODS

A total of 71 patients (age: 77 ± 9 years, females: 44%) with moderate-to-severe or severe PMR (effective regurgitant orifice: 0.57 ± 0.31 cm2; regurgitant volume: 80 ± 34 mL; LV end-systolic diameter: 42 ± 12 mm) underwent TEER after a global assessment by the heart team. MW indices were evaluated before the procedure, at hospital discharge, and at 1-year follow-up. LV remodeling was described as the percentage variation in LVEDV between baseline and 1-year follow-up.

RESULTS

TEER caused an acute reduction in LVEF, global longitudinal strain (GLS), global MW index (GWI), work efficiency (GWE), and mechanical dispersion (MD) and a significant increase in wasted work (GWW). One year after the procedure, GLS, GWI, GWE, and MD recovered, whereas GWW remained significantly impaired. Baseline GWW (β = -0.29, p = 0.03) was an independent predictor of LV reverse remodeling at 1-year follow-up.

CONCLUSIONS

In patients with severe PMR undergoing TEER, the acute reduction in LV preload causes significant impairment to all the parameters of LV performance. Baseline GWW was the only independent predictor of LV reverse remodeling, suggesting that a lower myocardial energetic efficiency in the context of chronic preload increase might impact the left ventricular response to mitral regurgitation correction.

Considering Both GLS and MD for a Prognostic Value in Non-ST-Segment Elevated Acute Coronary Artery Syndrome

Global longitudinal strain (GLS) and mechanical dispersion (MD), as determined by 2D speckle tracking echocardiography, have been demonstrated to be reliable indicators of prognosis in a variety of cardiovascular illnesses. There are not many papers that discuss the prognostic significance of GLS and MD in a population with non-ST-segment elevated acute coronary syndrome (NSTE-ACS). Our study objective was to examine the predictive utility of the novel GLS/MD two-dimensional strain index in NSTE-ACS patients. Before discharge and four to six weeks later, echocardiography was performed on 310 consecutive hospitalized patients with NSTE-ACS and effective percutaneous coronary intervention (PCI). Cardiac mortality, malignant ventricular arrhythmia, or readmission owing to heart failure or reinfarction were the major end points. A total of 109 patients (35.16%) experienced cardiac incidents during the follow-up period (34.7 ± 8 months). The GLS/MD index at discharge was determined to be the greatest independent predictor of composite result by receiver operating characteristic analysis. The ideal cut-off value was -0.229. GLS/MD was determined to be the top independent predictor of cardiac events by multivariate Cox regression analysis. Patients with an initial GLS/MD > -0.229 that deteriorated after four to six weeks had the worst prognosis for a composite outcome, readmission, and cardiac death according to a Kaplan-Meier analysis (all p < 0.001). In conclusion, the GLS/MD ratio is a strong indicator of clinical fate in NSTE-ACS patients, especially if it is accompanied by deterioration.

Impaired cardiac mechanical synchrony revealed with increased myocardial work in women with advanced age

BACKGROUND

Whether the synchronous nature of the myocardium is sex-dependent or affected by the aging process remains unknown. This study aimed to determine the influence of sex and age on cardiac mechanical synchrony during controlled hemodynamic stress.

METHODS

Transthoracic speckle-tracking echocardiography analyses and central hemodynamics were assessed at rest and during moderate- to high-intensity exercise in healthy young (<45 yr) and older (≥45 yr) women (n = 32) and men (n = 34) matched by age, physical activity and exercise capacity. Left ventricular mechanical dyssynchrony (LVMD) was determined as the time to peak standard deviation (TPSD) of longitudinal and transverse strain and strain rates (LSR, TSR).

RESULTS

Physical activity, aerobic capacity, heart rate, blood pressure and LVMD at rest were similar between women and men in each age group (P > 0.05). The rate pressure product, an index of myocardial work, did not differ between sex and age groups at rest and during exercise at a given percentage of peak heart rate (P > 0.05). A consistent age effect was observed for transverse LVMD (P-for-age ≤ 0.011). Specifically, older women presented with marked increments (≥42 %) in TSR TPSD at all exercise levels compared with younger women (P ≤ 0.005). Sex per se did not generally affect LVMD.

CONCLUSION

A prevailing impairment of cardiac mechanical synchrony in the transverse axis of the left ventricle is revealed during conditions of elevated hemodynamic stress in women with advanced age.

Multi-modality imaging to guide the implantation of cardiac electronic devices in heart failure: is the sum greater than the individual components?

Heart failure is a clinical syndrome with an increasing prevalence and incidence worldwide that impacts patients' quality of life, morbidity, and mortality. Implantable cardioverter-defibrillator and cardiac resynchronization therapy are pillars of managing patients with HF and reduced left ventricular ejection fraction. Despite the advances in cardiac imaging, the assessment of patients needing cardiac implantable electronic devices relies essentially on the measure of left ventricular ejection fraction. However, multi-modality imaging can provide important information concerning the aetiology of heart failure, the extent and localization of myocardial scar, and the pathophysiological mechanisms of left ventricular conduction delay. This paper aims to highlight the main novelties and progress in the field of multi-modality imaging to identify patients who will benefit from cardiac resynchronization therapy and/or implantable cardioverter-defibrillator. We also want to underscore the boundaries that prevent the application of imaging-derived parameters to patients who will benefit from cardiac implantable electronic devices and orient the choice of the device. Finally, we aim at providing some reflections for future research in this field.

Peak exercise myocardial deformation indices during cardiopulmonary exercise testing are associated with exercise capacity and ventilatory efficiency in patients with dilated cardiomyopathy

OBJECTIVE

Little is known about the exercise-induced changes in the multidimensional mechanical properties of the heart. We aimed to evaluate the myocardial deformation indices (MDI) at rest and their response at peak exercise during the same cardiopulmonary exercise testing (CPET) session, investigating their relationship to exercise capacity and ventilatory sufficiency in dilated cardiomyopathy (DCM) patients.

METHODS

We evaluated left ventricular (LV) function using speckle tracking imaging (STI) at rest and peak exercise during the same CPET session in 57 idiopathic DCM patients in New York Heart Association (NYHA) I-II class [54 ± 12 years, 42 males, ejection fraction (EF) 33 ± 9%]. We measured global longitudinal strain (GLS), longitudinal strain rate at systole (LSRS) and diastole (LSRD), and circumferential strain rate (CircS).

RESULTS

Resting GLS, LSRS, and LSRD were impaired compared with the predicted values but were improved at peak exercise (p < 0.001). All MDI at rest and/or at peak exercise were related to several CPET-derived parameters, including peak VO₂, load, O₂ pulse, and VE/VCO₂ slope. Peak exercise LSRS > -1.10 sec^-1 (AUC = 0.80, p < 0.001) and GLS > -13% (AUC = 0.81, p = 0.002) predicted impaired exercise capacity (peak VO₂ < 20 ml/min/kg) and ventilatory inefficiency (VE/VCO₂ slope>34). In multiple regression analysis, peak exercise LSRS and GLS were independently related to the peak VO₂ (Beta = -0.39, p = 0.003) and VE/VCO₂ slope (Beta = 0.35, p = 0.02), respectively.

CONCLUSIONS

Peak exercise LSRS and GLS in NYHA I-II DCM patients subjected to CPET were associated with aerobic exercise capacity and ventilatory efficiency. Consequently, LSRS and GLS at peak exercise, through their association with CPET-derived CV risk indices, may underline the severity of heart failure and predict future CV events in this DCM population.

Phase analysis for ventricular arrhythmia prediction: A retrospective monocentric cohort study

BACKGROUND

Prediction of ventricular arrhythmias (VA) mostly relies on left ventricular ejection fraction (LVEF), but with limited performance. New echocardiographic parameters such as mechanical dispersion have emerged, but acoustic window sometimes precludes this measurement. Nuclear imaging may be an alternative. We aimed to assess the ability of mechanical dispersion, measured with phase standard deviation (PSD) on radionuclide angiocardiography (RNA), to predict VAs.

METHODS

This retrospective monocentric observational study included all patients who underwent a tomographic RNA from 2015 to 2019. Phase analysis yielded PSD and follow-up was examined to identify VAs, heart transplantation, and death.

RESULTS

The study population consisted of 937 patients, mainly with LVEF ≤ 35% (425, 45%). Most had ischemic (334, 36%) or dilated cardiomyopathies (245, 26%). We identified 86 (9%) VAs. PSD was strongly associated with the occurrence of VA [hazard ratio per 10 ms increase (HR10) 1.12 (1.09-1.16)], heart transplantation [HR10 1.09 (1.06-1.12)], and death [HR10 1.03 (1.00-1.05)]. The association between PSD and VA persisted after adjustment for age, sex, QRS duration, LVEF, global longitudinal strain (GLS), and echocardiography-assessed mechanical dispersion.

CONCLUSION

The occurrence of ventricular arrhythmias was predicted by mechanical dispersion assessed by RNA, even after adjustment for LVEF and GLS.

Imaging for risk stratification of sudden cardiac death

Sudden cardiac death (SCD) can be effectively prevented with the use of implantable cardioverter-defibrillator (ICD). Current guidelines advocate an ICD for primary prevention in the presence of an left ventricular ejection fraction (LVEF) ≤ 35%. The majority of individuals that experience SCD, however, have an LVEF > 35%. Multimodality cardiac imaging has the ability to visualize the three factors responsible for arrhythmia-mediated SCD, namely substrate, trigger and modulator. Advances in cardiac imaging techniques have allowed improved SCD risk stratification, especially in the group of patients with an LVEF > 35%. However, clinical integration of cardiac imaging for SCD risk stratification will require more comparative data between modalities and parameters, as well as evidence of an impact on outcomes. The current review represents an update on the use of multimodality imaging techniques for SCD risk stratification.

Behind Enemy Lines: Vital Echocardiographic Data Prior to Ventricular Arrhythmia Ablation

Ventricular arrhythmias (VA) are a major cause of sudden cardiac death (SCD). Echocardiography is the first widely available imaging tool which guides VA management strategies. Along with other invasive and noninvasive imaging techniques, it provides essential information for identification of VA substrate such as differentiation between ischemic and non-ischemic etiology and identification of structural heart disease. Both classic as well as novel echocardiographic techniques such as left ventricular strain measurement and mechanical dispersion assessment provide prognostic information and assist in risk stratification. Furthermore, intracardiac echocardiography may have an adjunctive role for the VA ablation by providing real-time visualization of cardiac structures, continuous monitoring of catheter location and early recognition of procedural complications. This review gathers all relevant information that echocardiography may offer prior to VA ablation procedures.

Post-systolic shortening index by echocardiography evaluation of dyssynchrony in the non-dilated and hypertrophied left ventricle

Background

Post-systolic shortening index (PSI) is defined as myocardial shortening that occurs after aortic valve closure, and is an emerging measure of regional LV contractile dysfunction. PSI measurement variability amongst software vendor and its relationship with mechanical dyssynchrony and mechanical dispersion index (MDI) remains unknown. We evaluated PSI by speckle-tracking echocardiography from several vendors in patients with increased left ventricular wall thickness, and associations with MDI.

Methods

This is a prospective cross-sectional study of 70 patients (36 hypertrophic cardiomyopathy [HCM], 18 cardiac amyloidosis and 16 healthy controls) undergoing clinically indicated echocardiography. PSI was measured using QLAB/aCMQ (Philips), QLAB/LV auto-trace (Philips), EchoPAC (GE), Velocity Vector Imaging (Siemens), and EchoInsight (EPSILON) software packages, and calculated as 100%×(post systolic strain–end-systole strain)/post systolic strain.

Results

There was a significant difference in mean PSI among controls 2.1±0.6%, HCM 6.1±2.6% and cardiac amyloidosis 6.8±2.7% (p <0.001). Variations between software vendors were significant in patients with pathologic increases in LV wall thickness (for HCM p = 0.03, for amyloidosis p = 0.008), but not in controls (p = 0.11). Furthermore, there were moderate correlations between PSI and both MDI (r = 0.77) and left ventricular global longitudinal strain (r = 0.69).

Conclusion

PSI was greater in HCM and cardiac amyloidosis patients than controls, and a valuable tool for dyssynchrony evaluation, with moderate correlations to MDI and strain. However, there were significant variations in PSI measurements by software vendor especially in patients with pathological increase in LV wall thickness, suggesting that separate vendor-specific thresholds for abnormal PSI are required.

Echocardiography Assessment of Cardiac Function in Adults Living with HIV: A Speckle Tracking Study in the Era of Antiretroviral Therapy

Adults living with HIV (human immunodeficiency virus) infection (ALHIV) have high rates of cardiovascular events. New approaches are needed to detect subclinical cardiac dysfunction. We used conventional and speckle tracking echocardiography to investigate whether ALHIV display latent cardiac dysfunction. We analyzed 85 young subjects with HIV infection and free from cardiovascular risk factors (31 ± 4 years) and 80 matched healthy volunteers. We measured left ventricular (LV) layered global longitudinal strain, circumferential strain, peak longitudinal strain in the reservoir and contraction phases of the left atrium (LASr respectively LASct). In the HIV group, LV ejection fraction and s’ TDI (tissue doppler imaging) were slightly lower but still in the normal ranges. Layered longitudinal strain showed no significant difference, whereas circumferential global strain was significantly lower in the HIV group (−20.3 ± 3.9 vs. −22.3 ± 3.0, p < 0.001). LASr (34.3% ± 7.3% vs. 38.0% ± 6.9%, p < 0.001) was also lower in ALHIV and multivariate analysis showed that age (β = −0.737, p = 0.01) and infection duration (β = −0.221, p = 0.02) were independently associated with LASr. In the absence of cardiovascular risk factors, adults living with HIV display normal LV systolic function. Left atrial reservoir strain, is, however, decreased and suggests early diastolic dysfunction.

Contemporary Diagnosis and Management of Hypertrophic Cardiomyopathy: The Role of Echocardiography and Multimodality Imaging

Hypertrophic cardiomyopathy (HCM) is an underdiagnosed genetic heart disease with an estimated prevalence of 0.2-0.5%. Although the prognosis of HCM is relatively good, with an annual general mortality of ~0.7%, some patients have an increased risk of sudden death, or of developing severe heart failure requiring heart transplantation or left ventricular (LV) assist device therapy. Therefore, earlier diagnosis and proper identification of high-risk patients may reduce disease-related morbidity/mortality by promoting timely treatment. Echocardiography is the primary imaging modality for patients with suspected HCM; it plays central roles in differential diagnosis from other causes of LV hypertrophy and in evaluating morphology, hemodynamic disturbances, LV function, and associated valvular disease. Echocardiography is also an essential tool for the continuous clinical management of patients with confirmed HCM. Other imaging modalities, such as cardiac computed tomography (CT) and cardiac magnetic resonance imaging (MRI), can supplement echocardiography in identifying high-risk as well as milder HCM phenotypes. The role of such multimodality imaging has been steadily expanding along with recent advancements in surgical techniques and minimally invasive procedures, and the emergence of novel pharmacotherapies directly targeting pathogenic molecules such as myosin inhibitors. Here we review essential knowledge surrounding HCM with a specific focus on structural and functional abnormalities assessed by imaging modalities, leading to treatment strategies.

Predictors of Hospital Admissions for Ventricular Arrhythmia or Cardiac Arrest in Patients With Cardiomyopathy

Although ventricular dysfunction is associated with the occurrence of ventricular arrhythmia (VA), most patients with cardiomyopathy do not experience VA. We therefore investigated other predictors of VA in a large contemporary cohort of patients with cardiomyopathy. All patients at a large academic medical system with left ventricular ejection fraction (LVEF) ≤50% were enrolled at the time of first documented low LVEF. Predictors of hospital admission for VA were examined using multivariable Cox models. The incidence of implantable defibrillator (ICD) placement was also examined. A total of 18,003 patients were enrolled. Over a median follow-up of 3.35 years, 389 patients (2.2%) were admitted for VA (304 of 12,037 [2.5%] among patients with LVEF ≤35% vs 85 of 5,966 [1.4%] among those with LVEF 36% to 50%). Predictors of VA hospitalization included lower LVEF (hazard ratio (HR) = 1.43 per 10% decrease, p <0.001), the presence of an ICD at baseline (HR = 1.63, p = 0.010), higher blood glucose (HR = 1.02 per 10 mg/100 ml increase, p = 0.050), the presence of end-stage renal disease (HR = 3.59, p <0.001), and the presence of liver cirrhosis (HR = 1.93, p = 0.013). During follow-up, 626 patients were implanted with a new ICD. In addition to being admitted with VA, a lower LVEF and a history of coronary artery disease or heart failure were the main predictors of ICD therapy in this population. In conclusion, in addition to more severe cardiomyopathy and the presence of an implanted ICD, metabolic derangements on initial contact are independent predictors of hospital admissions for VA in patients with cardiomyopathy. Noncardiac co-morbidities play an important role in stratifying patients with cardiomyopathy for their risk of VA or cardiac arrest.

Echocardiographic predictors of ventricular arrhythmias in patients with non-ischemic cardiomyopathy

Objective

Methods

Results

Conclusion

Noninvasive Evaluation of Myocardial Work in Patients with Chronic Kidney Disease Using Left Ventricular Pressure-Strain Loop Analysis

(1) Objective: To evaluate myocardial injury by observing the different parameters of global myocardial work (MW) by left ventricular pressure-strain loop (PSL) analysis in patients with chronic kidney disease (CKD). (2) Methods: According to the left ventricular mass index, the study patients with CKD were further divided into two groups: the left ventricular normal group (CKD_N-LVH, 59) and left ventricular hypertrophy group (CKD_LVH, 46). Thirty-three healthy controls (CON) matched in age and sex with the CKD group were recruited. The routine ultrasonic parameters were obtained by routine TTE, and the strain index and different parameters of the left ventricular MW were obtained by dynamic image offline analysis. (3) Results: This study found that (1) compared with the CON group, the CKD_N-LVH group had a significantly increased global waste work (GWW) and significantly decreased global work efficiency (GWE), the GWW further increased, and GWE further decreased in the CKD_LVH group. There was no significant change in the global work index (GWI) and global constructive work index (GCW) in the CKD_N-LVH group, but the GWI and GCW in the CKD_LVH group were significantly increased. (2) According to the grouping analysis of systolic blood pressure (SBP), we found that the GWW increased and GWE decreased in CKD patients with an elevated SBP. (3) Correlation analysis showed that the increase of the peak strain dispersion, SBP, and left ventricular mass index and the decrease of the estimated glomerular filtration rate were significantly correlated with the decrease of the GWE and the increase of the GWW. (4) Receiver operating characteristic curve analysis showed that the area under the curve (AUC) of myocardial damage induced by the GWE and GWW in the CKD group and CON group was higher than that of left ventricular global longitudinal strain (AUCs: 0.87 and 0.878 versus 0.72, respectively). (4) Conclusions: Noninvasive left ventricular PSL analysis can be used to evaluate the global MW in patients with CKD. The study justified the role of GWW in the noninvasive assessment of myocardial function in patients with CKD.

Associations between cardiovascular risk factors, biomarkers, and left ventricular mechanical dispersion: insights from the ACE 1950 Study

Aims

Mechanical dispersion measures left ventricular contraction heterogeneity and is associated with the risk of sudden cardiac death. However, the associations between mechanical dispersion and cardiovascular risk factors in early mid-life, and established biomarkers of sub-clinical myocardial injury and dysfunction are not known. We aimed to examine this in the general population.

Methods and results

During 2012–15, we included 2527 Norwegian individuals from the general population born in 1950, with measurements of mechanical dispersion by 2D speckle tracking echocardiography and concentrations of high-sensitivity cardiac troponin T (hs-cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) available. Mechanical dispersion was calculated as the standard deviation of the contraction duration of 17 strain segments. We assessed the associations between mechanical dispersion, concentrations of hs-cTnT and NT-proBNP, and cardiovascular risk factors collected at a national health screening survey two decades earlier. At echocardiography baseline, median age was 64 (interquartile range 63.5–64.5) years, 49.8% were women, 59.1% had hypertension, and 5.9% reported established coronary artery disease. Median mechanical dispersion was 38.0 (29.5–47.0) ms, median hs-cTnT concentration 6 (4–8) ng/L, and the median NT-proBNP concentration 54 (34–93) ng/L. Mechanical dispersion was associated with both hs-cTnT and NT-proBNP concentrations in multivariable models adjusted for clinical and echocardiographic variables. High body mass index, serum triglyceride concentrations, and low resting heart rate at Age 40 were independently associated with increased mechanical dispersion two decades later.

Conclusion

Established risk factors at Age 40 are associated with mechanical dispersion two decades later, and mechanical dispersion is cross-sectionally associated with biomarkers of subclinical myocardial injury and dysfunction.

Electrophysiologic effects of sacubitril in different arrhythmia models

BACKGROUND

Previous studies report conflicting data regarding anti- or proarrhythmic effects of sacubitril. Aim of this study was to assess the impact of acute sacubitril treatment in different arrhythmia models.

METHODS

Sacubitril was administered (3, 5, 10 μM) in 12 isolated rabbit hearts. Further 12 hearts were treated with erythromycin to simulate long-QT-syndrome-2 (LQT2). Other 12 hearts were perfused with veratridine to mimic long-QT-syndrome-3 (LQT3). Both LQT-groups were treated with sacubitril (5 μM) additionally. Ventricular vulnerability was assessed by a pacing protocol. AV-blocked bradycardic hearts were perfused with a hypokalemic solution to trigger torsade de pointes (TdP). In further 13 hearts, AF was induced by a combination of acetylcholine and isoproterenol and sacubitril (5 μM) was added afterwards.

RESULTS

With sacubitril, action potential duration (APD) was abbreviated whereas spatial dispersion of repolarisation (SDR) remained stable. In both LQT groups, APD and SDR were increased. Infusion of sacubitril reduced APD (- 21 ms, p < 0.01) and SDR (- 8 ms) in the LQT2-group and did not alter APD (+2 ms) but reduced SDR (-19 ms, p < 0.01) in the LQT3-group. Ventricular vulnerability was not altered by sacubitril. No TdP were observed with sacubitril or under baseline conditions in any group. Sacubitril significantly suppressed TdP in the LQT2-group (3 vs. 43 episodes, p < 0.05) but not in the LQT3-group (10 vs. 16 episodes, p = ns). Sacubitril reduced inducibility of AF (9 vs. 31 episodes).

CONCLUSION

Sacubitril abbreviated APD. In addition, sacubitril exhibits potential antiarrhythmic effects in LQT2 and may be beneficial in LQT3 and AF.

Evolving concept of dyssynchrony and its utility

The role of electromechanical dyssynchrony in heart failure gained prominence in literature with the results of trials of cardiac resynchronization therapy (CRT). CRT has shown to significantly decrease heart failure hospitalization and mortality in heart failure patients with dyssynchrony. Current guidelines recommend the use of electrical dyssynchrony based on a QRS > 150 ms and a left bundle branch block pattern on surface electrocardiogram to identify dyssynchrony in patients who will benefit from CRT implantation. However, predicting response to CRT remains a challenge with nearly one-third of patients gaining no benefit from the device. Multiple echocardiographic measures of mechanical dyssynchrony have been studied over the past two decade. However, trials where mechanical dyssynchrony used as an additional or lone criteria for CRT failed to show any benefit in the response to CRT. This shows that a deeper understanding of cardiac mechanics should be applied in the assessment of dyssynchrony. This review discusses the evolving role of imaging techniques in assessing cardiac dyssynchrony and their application in patients considered for device therapy.

Beyond Ejection Fraction: Novel Clinical Approaches Towards Sudden Cardiac Death Risk Stratification in Patients with Dilated Cardiomyopathy

Implantable Cardioverter-Defibrillator (ICD) therapy is indicated for patients at risk for sudden cardiac death due to ventricular tachyarrhythmia. The most commonly used risk stratification algorithms use Left Ventricular Ejection Fraction (LVEF) to determine which patients qualify for ICD therapy, even though LVEF is a better marker of total mortality than ventricular tachyarrhythmias mortality. This review evaluates imaging tools and novel biomarkers proposed for better risk stratifying arrhythmic substrate, thereby identifying optimal ICD therapy candidates.

Quality Assurance of Segmental Strain Values Provided by Commercial 2-D Speckle Tracking Echocardiography Using in Silico Models: A Report from the EACVI-ASE Strain Standardization Task Force

The aim of this study was to determine the accuracy and reproducibility of vendor-specific regional strain values by echocardiography using in silico data. Synthetic 2-D ultrasound gray-scale images of the left ventricle (LV) were generated with knowledge of the longitudinal segmental strain values from the underlying electromechanical LV model. Four of five models mimicked transmural infarctions with systolic segmental stretching in different vascular areas. Cine loops in the three apical views were synthetically generated at four noise levels. All in silico images were repeatedly analyzed by a single investigator and some by another investigator. The absolute errors varied significantly between vendors from 3.3 ± 3.1% to 11.2 ± 5.9%. The area under the curve for the identification of segmental stretching ranged from 0.80 (confidence interval: 0.77-0.83) to 0.96 (0.95-0.98). The levels of agreement for intra-investigator variability varied between -3.0% to 2.9% and -5.2% to 4.8%, and for inter-investigator variability, between -3.6% to 3.5% and -14.5% to 8.5%. Segmental strain analysis allows the identification of areas with segmental stretching with good accuracy. However, single segmental peak-strain values are not accurate and should be interpreted with caution. Nevertheless, our results indicate the usefulness of semiquantitative strain assessment for the detection of regional dysfunction.

Burden of Ventricular Arrhythmias in Cardiac Resynchronization Therapy Defibrillation and Implantable Cardioverter-Defibrillator Recipients with Recovered Left Ventricular Ejection Fraction: The Additive Role of Speckle-Tracking Echocardiography

BACKGROUND

Patients with heart failure undergoing cardiac resynchronization therapy with or without defibrillator function may exhibit recovery of left ventricular ejection fraction (LVEF) during follow-up. Mechanical dispersion (MD; the SD of time to peak longitudinal strain by two-dimensional speckle-tracking echocardiography) is a known predictor of life-threatening ventricular arrhythmias (VAs). Relationships among LVEF recovery, changes in MD, and incidence of VA are still not extensively investigated.

METHODS

In this retrospective study, recipients of cardiac resynchronization therapy defibrillation (n = 183) or implantable cardioverter-defibrillators only (n = 87) underwent conventional and speckle-tracking echocardiography, both at baseline and after 10 to 12 months, and were followed clinically. Both a ≥10% increase in LVEF and a final LVEF > 35% defined echocardiographic response (Echo_Resp). Reduction in MD ≥10 msec defined MD response (MD_Resp). Risk for appropriate implantable cardioverter-defibrillator therapy for VAs was assessed using a multivariable Cox hazard model.

RESULTS

The prevalence of Echo_Resp+ and MD_Resp+ was 39% and 46%, respectively. During follow-up (49.8 ± 33.5 months), 74 VA events occurred. The incidence rate (per 100 patient-years) of VAs was lowest in the Echo_Resp+/MD_Resp+ group (1.66%; 95% CI, 0.69%-3.99%), highest in the Echo_Resp-/MD_Resp- group (12.8%; 95% CI, 9.53%-17.2%; P < .0001), and intermediate in the Echo_Resp-/MD_Resp+ (5.5%; 95% CI, 3.3%-9.4%) or Echo_Resp+/MD_Resp- (5.3%; 95% CI, 3.0%-9.4%) group. Multivariable analysis showed that higher MD at follow-up (>71.4 msec) was associated with VAs independent of whether final LVEF was below or above the guideline-reported cutoff of 35% (P < .05).

CONCLUSIONS

Among ICD recipients, improvements in both left ventricular function and MD are associated with reduced risk for VAs. In patients whose follow-up LVEFs improved to >35%, risk for VAs, although substantially decreased, remained elevated in the presence of still elevated MD.

Echocardiographic Longitudinal Strain Analysis in Heart Failure: Real Usefulness for Clinical Management Beyond Diagnostic Value and Prognostic Correlations? A Comprehensive Review

Heart failure (HF) is a highly prevalent clinical syndrome characterized by considerable phenotypic heterogeneity. The traditional classification based on left ventricular ejection fraction (LVEF) is widely accepted by the guidelines and represents the grounds for patient enrollment in clinical trials, even though it shows several limitations. Ejection fraction (EF) is affected by preload, afterload, and contractility, it being problematic to express LV function in several conditions, such as HF with preserved EF (HFpEF), valvular heart disease, and subclinical HF, and in athletes. Over the last two decades, developments in diagnostic techniques have provided useful tools to overcome EF limitations. Strain imaging analysis (particularly global longitudinal strain (GLS)) has emerged as a useful echocardiographic technique in patients with HF, as it is able to simultaneously supply information on both systolic and diastolic functions, depending on cardiac anatomy and physiology/pathophysiology. The use of GLS has proved helpful in terms of diagnostic performance and prognostic value in several HF studies. Universally accepted cutoff values and variability across vendors remain an area to be fully explored, hence limiting routine application of this technique in clinical practice. In the present review, the current role of GLS in the diagnosis and management of patients with HF will be discussed. We describe, by critical analysis of the pros and cons, various clinical settings in HF, and how the appropriate use and interpretation of GLS can provide important clues.

Strain echocardiography improves prediction of arrhythmic events in ischemic and non-ischemic dilated cardiomyopathy

BACKGROUND

Recent evidence suggests that an implantable cardioverter defibrillator (ICD) in non-ischemic cardiomyopathy (NICM) may not offer mortality benefit. We aimed to investigate if etiology of heart failure and strain echocardiography can improve risk stratification of life threatening ventricular arrhythmia (VA) in heart failure patients.

METHODS

This prospective multi-center follow-up study consecutively included NICM and ischemic cardiomyopathy (ICM) patients with left ventricular ejection fraction (LVEF) <40%. We assessed LVEF, global longitudinal strain (GLS) and mechanical dispersion (MD) by echocardiography. Ventricular arrhythmia was defined as sustained ventricular tachycardia, sudden cardiac death or appropriate shock from an ICD.

RESULTS

We included 290 patients (67 ± 13 years old, 74% males, 207(71%) ICM). During 22 ± 12 months follow up, VA occurred in 32(11%) patients. MD and GLS were both markers of VA in patients with ICM and NICM, whereas LVEF was not (p = 0.14). MD independently predicted VA (HR: 1.19; 95% CI 1.08-1.32, p = 0.001), with excellent arrhythmia free survival in patients with MD <70 ms (Log rank p < 0.001). Patients with NICM and MD <70 ms had the lowest VA incidence with an event rate of 3%/year, while patients with ICM and MD >70 ms had highest VA incidence with an event rate of 16%/year.

CONCLUSION

Patients with NICM and normal MD had low arrhythmic event rate, comparable to the general population. Patients with ICM and MD >70 ms had the highest risk of VA. Combining heart failure etiology and strain echocardiography may classify heart failure patients in low, intermediate and high risk of VA and thereby aid ICD decision strategies.

Left ventricular mechanical dispersion in a general population: Data from the Akershus Cardiac Examination 1950 study

AIMS

Increased left ventricular mechanical dispersion by 2D speckle tracking echocardiography predicts ventricular arrhythmias in ischaemic heart disease and heart failure. However, little is known about mechanical dispersion in the general population. We aimed to study mechanical dispersion in the general population and in diseases associated with increased risk of cardiovascular disease.

METHODS AND RESULTS

The present cross-sectional study consists of 2529 subjects born in 1950 included in the Akershus Cardiac Examination (ACE) 1950 study. Global longitudinal strain (GLS) was assessed from 17 strain segments, and mechanical dispersion calculated as the standard deviation of contraction duration of all segments. The cohort was divided according to the median value of mechanical dispersion, and multivariable linear regression models were performed with mechanical dispersion as the dependent variable. The prevalence of coronary artery disease (CAD), hypertension, obesity, and diabetes (P < 0.01 for all) was significantly higher in subjects with supra-median mechanical dispersion. In a multivariable clinical model, CAD (B = 7.05), hypertension (B = 4.15; both P < 0.001), diabetes (B = 3.39), and obesity (B = 1.89; both P < 0.05) were independently associated with increasing mechanical dispersion. When echocardiographic indices were added to the multivariable model, CAD (B = 4.38; P < 0.01) and hypertension (B = 2.86; P < 0.001) remained significant in addition to peak early diastolic tissue velocity e' (B = -2.00), GLS (B = 1.68), and ejection fraction (B = 0.22; P < 0.001 for all).

CONCLUSION

In a general middle-aged population, prevalent CAD and hypertension were associated with increasing mechanical dispersion, possibly indicating elevated risk of fatal arrhythmias and sudden cardiac death. Albeit weaker, systolic and diastolic dysfunction, were also associated with increasing mechanical dispersion.

Assessing left ventricular systolic function: from ejection fraction to strain analysis

The measurement of left ventricular ejection fraction (LVEF) is a ubiquitous component of imaging studies used to evaluate patients with cardiac conditions and acts as an arbiter for many management decisions. This follows early trials investigating heart failure therapies which used a binary LVEF cut-off to select patients with the worst prognosis, who may gain the most benefit. Forty years on, the cardiac disease landscape has changed. Left ventricular ejection fraction is now a poor indicator of prognosis for many heart failure patients; specifically, for the half of patients with heart failure and truly preserved ejection fraction (HF-PEF). It is also recognized that LVEF may remain normal amongst patients with valvular heart disease who have significant myocardial dysfunction. This emphasizes the importance of the interaction between LVEF and left ventricular geometry. Guidelines based on LVEF may therefore miss a proportion of patients who would benefit from early intervention to prevent further myocardial decompensation and future adverse outcomes. The assessment of myocardial strain, or intrinsic deformation, holds promise to improve these issues. The measurement of global longitudinal strain (GLS) has consistently been shown to improve the risk stratification of patients with heart failure and identify patients with valvular heart disease who have myocardial decompensation despite preserved LVEF and an increased risk of adverse outcomes. To complete the integration of GLS into routine clinical practice, further studies are required to confirm that such approaches improve therapy selection and accordingly, the outcome for patients.

Evaluation of left ventricular systolic synchrony by peak strain dispersion in patients with rheumatoid arthritis

Objective

To investigate the clinical value of the peak strain dispersion (PSD) in evaluating left ventricular (LV) systolic synchrony in patients with rheumatoid arthritis (RA).

Methods

One hundred eleven patients with RA were divided into two groups according to their disease duration: <5 years (Group I, n = 60) and ≥5 years (Group II, n = 51). The control group comprised 57 healthy subjects without RA. All three groups were examined by transthoracic two-dimensional echocardiography. Traditional parameters were measured by conventional echocardiography. Two-dimensional speckle tracking imaging was used to analyze the PSD and LV global longitudinal strain (LVGLS). Related ultrasound and blood test results were analyzed and compared.

Results

The PSD gradually increased in the order of the control group, Group I, and Group II, and the difference among the groups was statistically significant. The LVGLS gradually decreased in the order of the control group, Group I, and Group II, and the difference among the groups was statistically significant. The PSD was negatively correlated with the LVGLS.

Conclusions

LV systolic synchrony in patients with RA gradually decreases as the disease course progresses. The PSD can be used as a new reliable index to evaluate LV systolic synchrony.