Postsystolic shortening in ischemic myocardium: active contraction or passive recoil?

Risk profiles for ventricular arrhythmias in hypertrophic cardiomyopathy through clustering analysis including left ventricular strain

AIMS

The prediction of ventricular arrhythmia (VA) in hypertrophic cardiomyopathy (HCM) remains challenging. We sought to characterize the VA risk profile in HCM patients through clustering analysis combining clinical and conventional imaging parameters with information derived from left ventricular longitudinal strain analysis (LV-LS).

METHODS

A total of 434 HCM patients (65% men, mean age 56 years) were included from two referral centers and followed longitudinally (mean duration 6 years). Mechanical and temporal parameters were automatically extracted from the LV-LS segmental curves of each patient in addition to conventional clinical and imaging data. A total of 287 features were analyzed using a clustering approach (k-means). The principal endpoint was VA.

RESULTS

4 clusters were identified with a higher rhythmic risk for clusters 1 and 4 (VA rates of 26%(28/108), 13%(13/97), 12%(14/120), and 31%(34/109) for cluster 1,2,3 and 4 respectively). These 4 clusters differed mainly by LV-mechanics with a severe and homogeneous decrease of myocardial deformation for cluster 4, a small decrease for clusters 2 and 3 and a marked deformation delay and temporal dispersion for cluster 1 associated with a moderate decrease of the GLS (p < 0.0001 for GLS comparison between clusters). Patients from cluster 4 had the most severe phenotype (mean LV mass index 123 vs. 112 g/m2; p = 0.0003) with LV and left atrium (LA) remodeling (LA-volume index (LAVI) 46.6 vs. 41.5 ml/m2, p = 0.04 and LVEF 59.7 vs. 66.3%, p < 0.001) and impaired exercise capacity (% predicted peak VO2 58.6 vs. 69.5%; p = 0.025).

CONCLUSION

Processing LV-LS parameters in HCM patients 4 clusters with specific LV-strain patterns and different rhythmic risk levels are identified. Automatic extraction and analysis of LV strain parameters improves the risk stratification for VA in HCM patients.

Myocardial motion in acute ischemia: revealing invisible deformation by echocardiography

Echocardiography has been used clinically to assess regional myocardial wall motion for the diagnosis of acute myocardial ischemia or stress-induced ischemia, but it is often difficult to distinguish hypokinetic motion from normal motion. Myocardial wall motion is affected by loading conditions as well as intrinsic contractility, making it challenging to define a normal range of wall motion. Therefore, hypokinesis is usually diagnosed by comparing target areas with other areas of myocardium considered normal (relative hypokinesis). Myocardial strain analysis by tissue Doppler echocardiography and speckle-tracking echocardiography has enabled objective and quantitative evaluation of regional myocardial wall motion. Peak systolic strain decreases during acute ischemia, but subtle and invisible myocardial motion, such as early systolic lengthening (ESL) and postsystolic shortening (PSS), also occurs, and the analysis of these subtle motions can improve the diagnostic accuracy of ischemia. However, the diagnosis of ischemic myocardium by strain analysis is not widely performed in clinical practice at this time due to several limitations. This article reviews the features of myocardial motion during acute ischemia, the mechanisms of ESL and PSS, the diagnosis of ischemic myocardium using strain analysis, and current approaches and future challenges to overcome the limitations in the detection of relative hypokinesis. This article also explains the use of ESL and PSS to detect myocardial ischemic memory that remains after brief ischemia.

Strain imaging as an early predictor in acute myocardial infarction - An augmented cross-sectional study

INTRODUCTION

Cardiac fibres are affected invariably in myocardial infarction, with longitudinal strain being the earliest to be detected in the ischaemic cascade. The present study aims to assess strain imaging in acute myocardial infarction (AMI) patients admitted to the cardiology department at our institute and correlate GLS and DESL findings with other markers for myocardial function.

METHODS AND MATERIAL

This augmented cross-sectional study was conducted amongst the patients admitted with diagnosis of AMI. During the study period, 157 subjects were sampled through convenience sampling, and examined as well as tested with routine investigations at baseline. The subjects were then followed through at first, third and six months, and findings noted. Chi-square was used to assess the crude association between sample characteristics. Pearson correlation and student t-test were used to find association between continuous variables.

RESULTS

After screening 564 patients, 157 patients were included in the study after fulfilment of inclusion and exclusion criteria. A significant difference was found in baseline GLS scores and NTproBNP levels at 6 months in alive patients with STEMI, t (21.728) = -5.717, p < .001. Out of the 50 NSTEMI patients, 35 (70 %) were positive for ESL, similarly out of 43 STEMI patients without any RWMA, ESL was positive in 39 (90.02 %) patients.

CONCLUSIONS

GLS by STE has good correlation with LVEF, WMSI and NT pro-BNP and it is an independent predictor of mortality and heart failure among patients with AMI.

Segmental myocardial viability by echocardiography at rest

BACKGROUND

Myocardial viability assessment adds value to the therapeutic decision-making of patients with ischemic heart disease. In this feasibility study, we investigated whether established echocardiographic measurements of post-systolic shortening (PSS), strain, strain rate and wall motion score (WMS) can discover viable myocardial segments. Our hypothesis is that non-viable myocardial segments are both akinetic and without PSS.

METHODS

The study population consisted of 26 examinations strictly selected by visible dysfunction. We assessed WMS, strain by speckle tracking and strain rate by tissue Doppler. The segments (16*26 = 416) were categorized into either normokinetic/hypokinetic or akinetic/dyskinetic and whether there was PSS. The reference method was the presence of scar with segmental percentage volume scar fraction >50%, detected by late gadolinium-enhanced cardiovascular magnetic resonance. Agreement with echocardiography was evaluated by Kappa coefficient.

RESULTS

WMS had Kappa coefficient 0.43 (sensitivity 99%, specificity 35%). Kappa coefficient of strain was 0.28 (sensitivity 98%, specificity 23%). By combining PSS in akinetic segments with WMS and strain, the Kappa coefficient was 0.06 and 0.08 respectively.

CONCLUSION

Segmental viability was best shown by the presence of systolic function. Post-systolic shortening adds no value to the assessment of segmental myocardial viability.

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

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

The diagnostic accuracy of two-dimensional strain imaging echocardiography to detect the severity of coronary artery disease in non-ST segment elevation acute coronary syndrome

OBJECTIVE

Strain imaging by two-dimensional speckle tracking echocardiography can detect severe coronary artery disease (CAD). This study aims to assess the diagnostic accuracy of various strain parameters in patients with non-ST segment acute coronary syndrome to detect the angiographic severity of CAD and also to compare among them.

METHODS

This hospital-based observational study was conducted on 178 patients with NSTEACS and preserved left ventricular ejection fraction who presented in emergency or outdoor from July 2021 to December 2022. We excluded patients with prior coronary revascularization, heart failure, arrhythmia, more than trivial valvular heart disease, or poor acoustic window. Global longitudinal strain (GLS), peak systolic strain (SS), post systolic index (PSI), and systolic strain rate (SR) were calculated by speckle tracking with automated function imaging. Coronary angiography was done in all patients, and the syntax score was calculated.

RESULTS

The strain parameters showed a significant correlation with the syntax score. There was a statistically significant difference in strain parameters between patients with left main (LM) or triple vessel disease (TVD) and others. Receiver operating characteristic (ROC) curve analysis showed that GLS had a better diagnostic accuracy for detecting LM or TVD than other strain parameters. GLS with a cut-off value of -11.2% had a sensitivity of 85.7% and specificity of 53.5% for detecting LM or TVD.

CONCLUSION

Strain imaging can be a helpful bedside adjunct to conventional investigations for detecting severe CAD in patients with NSTEACS.

Association Between Segmental Noninvasive Myocardial Work and Microvascular Perfusion in ST-Segment Elevation Myocardial Infarction: Implications for Left Ventricular Functional Recovery and Clinical Outcomes

BACKGROUND

Predicting left ventricular recovery (LVR) after acute ST-segment elevation myocardial infarction (STEMI) is of prognostic importance. This study aims to explore the prognostic implications of segmental noninvasive myocardial work (MW) and microvascular perfusion (MVP) after STEMI.

METHODS

In this retrospective study, 112 patients with STEMI who underwent primary percutaneous coronary intervention and transthoracic echocardiography after percutaneous coronary intervention were enrolled. Microvascular perfusion was analyzed by myocardial contrast echocardiography, and segmental MW was analyzed by noninvasive pressure-strain loops. A total of 671 segments with abnormal function at baseline were analyzed. The degrees of MVP were observed following intermittent high-mechanical index impulses: replenishment within 4 seconds (normal MVP), replenishment >4 seconds and within 10 seconds (delayed MVP), and persistent defect (microvascular obstruction). The correlation between MW and MVP was analyzed. The correlation of the MW and MVP with LVR (normalization of wall thickening, >25%) was assessed. The prognostic value of segmental MW and MVP for cardiac events (cardiac death, admission for congestive heart failure, or recurrent myocardial infarction) was evaluated.

RESULTS

Normal MVP was seen in 70 segments, delayed MVP in 236, and microvascular obstruction in 365. The segmental MW indices were independently correlated with MVP; 244 (36.4%) segments had segmental LVR at 3-month follow-up. Segmental MW efficiency and MVP were independently associated with segmental LVR (P < .05). The χ2 of combination of segmental MW efficiency and MVP was higher than either index alone for identifying segmental LVR (P < .001). At a median follow-up of 42.0 months, cardiac events occurred in 13 patients; all regional MW parameters, high sensitivity troponin I, regional longitudinal strain, and so on were associated with cardiac events.

CONCLUSIONS

Segmental MW indices are associated with MVP within the infarct zone following reperfused STEMI. Both are independently associated with segmental LVR, and regional MW is associated with cardiac events, providing prognostic value in STEMI patients.

Multiaxial pressure-strain analysis of regional myocardial work in the setting of graded coronary stenoses and dobutamine stress

We present a detailed analysis of regional myocardial blood flow and work to better understand the effects of coronary stenoses and low-dose dobutamine stress. Our analysis is based on a unique open-chest model in anesthetized canines that features invasive hemodynamic monitoring, microsphere-based blood flow analysis, and an extensive three-dimensional (3-D) sonomicrometer array that provides multiaxial deformational assessments in the ischemic, border, and remote vascular territories. We use this model to construct regional pressure-strain loops for each territory and quantify the loop subcomponent areas that reflect myocardial work contributing to the ejection of blood and wasted work that does not. We demonstrate that reductions in coronary blood flow markedly alter the shapes and temporal relationships of pressure-strain loops, as well as the magnitudes of their total and subcomponent areas. Specifically, we show that moderate stenoses in the mid-left anterior descending coronary artery decrease regional midventricle myocardial work indices and substantially increase indices of wasted work. In the midventricle, these effects are most pronounced along the radial and longitudinal axes, with more modest effects along the circumferential axis. We further demonstrate that low-dose dobutamine can help to restore or even improve function, but often at the cost of increased wasted work. This detailed, multiaxial analysis provides unique insight into the physiology and mechanics of the heart in the presence of ischemia and low-dose dobutamine, with potential implications in many areas, including the detection and characterization of ischemic heart disease and the use of inotropic support for low cardiac output.NEW & NOTEWORTHY Our unique experimental model assesses cardiac pressure-strain relationships along multiple axes in multiple regions. We demonstrate that moderate coronary stenoses decrease regional myocardial work and increase wasted work and that low-dose dobutamine can help to restore myocardial function, but often with further increases in wasted work. Our findings highlight the significant directional variation of cardiac mechanics and demonstrate potential advantages of pressure-strain analyses over traditional, purely deformational measures, especially in characterizing physiological changes related to dobutamine.

Right ventricular postsystolic shortening: Resolution after opening a totally occluded right coronary artery

Acute myocardial ischemia induces reduced systolic shortening and causes postsystolic shortening (PSS). Right ventricular (RV) PSS in coronary artery disease has been less studied. We present here the case of a 51-year-old woman admitted with a non-ST segment elevation myocardial infarction and significant PSS in the RV free-wall segments on two-dimensional speckle tracking echocardiography, suggesting ongoing ischemia. A cardiac CT demonstrated occluded proximal right coronary artery with a low-attenuated/soft plaque, confirmed by coronary angiography which was treated by percutaneous coronary intervention. At 3-week follow-up, there was complete resolution of the RV-PSS, with a more synchronized pattern of maximum myocardial shortening at systole.

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.

Myocardial deformation indices for detection of the functional significance of intermediate left anterior descending coronary artery stenosis: FFR guided study

This study aimed to investigate the diagnostic performance of non-invasive resting myocardial deformation indices in identifying functional significance of intermediate stenosis of the left anterior descending (LAD) artery. Patients with 50–70% LAD stenosis upon coronary angiography were enrolled and divided into group I with fractional flow reserve (FFR) > 0.8 and group II with FFR ≤ 0.8. Patients were subjected to conventional and speckle tracking echocardiography with measurement of myocardial deformation indices including regional peak longitudinal strain (PLS), global longitudinal strain (GLS), Post-systolic strain index (PSI), and time interval between Aortic valve closure (AVC) and PLS. The current study included 200 patients. Group II patients had significantly lower absolute mean values of regional (PLS) and (GLS) compared to group I (− 14.98 ± 5.05 and − 18.73 ± 3.92 vs. − 17.59 ± 3.62 and − 19.20 ± 2.61, p = 0.001 and 0.02, respectively). The FFR values of LAD correlated significantly and negatively with the time interval between AVC and regional PLS (r = − 0.201, p = 0.004) as well as PSI (r = − 0.257, p < 0.001). For identifying cases with FFR ≤ 0.8, the optimal cut-off value of the time interval between AVC and PLS was 76 ms with 77.8% sensitivity and 93.8% specificity. The best cut-off value of PSI was 13%, yielding 50% sensitivity and 87.5% specificity. In patients with intermediate 50–70% LAD coronary artery stenotic lesions, the PSI and the duration between AVC and regional PLS enabled the identification of functionally significant lesions with reasonable diagnostic accuracy.

Trial registration ZU-IRB#3199-20-11-2015 Registered 20 November 2015, IRB_123@medicine.zu.edu.eg.

A Lumped Two-Compartment Model for Simulation of Ventricular Pump and Tissue Mechanics in Ischemic Heart Disease

Introduction: Computational modeling of cardiac mechanics and hemodynamics in ischemic heart disease (IHD) is important for a better understanding of the complex relations between ischemia-induced heterogeneity of myocardial tissue properties, regional tissue mechanics, and hemodynamic pump function. We validated and applied a lumped two-compartment modeling approach for IHD integrated into the CircAdapt model of the human heart and circulation.

Methods: Ischemic contractile dysfunction was simulated by subdividing a left ventricular (LV) wall segment into a hypothetical contractile and noncontractile compartment, and dysfunction severity was determined by the noncontractile volume fraction (NCVF). Myocardial stiffness was determined by the zero-passive stress length (Ls0,pas) and nonlinearity (kECM) of the passive stress-sarcomere length relation of the noncontractile compartment. Simulated end-systolic pressure volume relations (ESPVRs) for 20% acute ischemia were qualitatively compared between a two- and one-compartment simulation, and parameters of the two-compartment model were tuned to previously published canine data of regional myocardial deformation during acute and prolonged ischemia and reperfusion. In six patients with myocardial infarction (MI), the NCVF was automatically estimated using the echocardiographic LV strain and volume measurements obtained acutely and 6 months after MI. Estimated segmental NCVF values at the baseline and 6-month follow-up were compared with percentage late gadolinium enhancement (LGE) at 6-month follow-up.

Results: Simulation of 20% of NCVF shifted the ESPVR rightward while moderately reducing the slope, while a one-compartment simulation caused a leftward shift with severe reduction in the slope. Through tuning of the NCVF, Ls0,pas, and kECM, it was found that manipulation of the NCVF alone reproduced the deformation during acute ischemia and reperfusion, while additional manipulations of Ls0,pas and kECM were required to reproduce deformation during prolonged ischemia and reperfusion. Out of all segments with LGE>25% at the follow-up, the majority (68%) had higher estimated NCVF at the baseline than at the follow-up. Furthermore, the baseline NCVF correlated better with percentage LGE than NCVF did at the follow-up.

Conclusion: We successfully used a two-compartment model for simulation of the ventricular pump and tissue mechanics in IHD. Patient-specific optimizations using regional myocardial deformation estimated the NCVF in a small cohort of MI patients in the acute and chronic phase after MI, while estimated NCVF values closely approximated the extent of the myocardial scar at the follow-up. In future studies, this approach can facilitate deformation imaging–based estimation of myocardial tissue properties in patients with cardiovascular diseases.

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.

Post-systolic shortening is superior to global longitudinal strain in predicting adverse events in patients with stable coronary artery disease and preserved systolic function

Background

Post-systolic shortening (PSS) is an important indicator for early identifying myocardial dysfunction. We aimed to investigate the predictive value of PSS assessed with speckle tracking automated functional imaging (AFI) on adverse events in patients with stable coronary artery disease (CAD) and preserved systolic function.

Methods

A total of 204 consecutive patients clinically diagnosed with stable CAD and left ventricular ejection fraction (LVEF) > 50% were included. Multiple parameters were analyzed with AFI technique. The composite endpoint included all-cause mortality, heart failure, myocardial infarction and stroke.

Results

During a median follow-up of 24 months (IQR 19–28 months), 30 patients (14.7%) reached the endpoint. Patients experiencing the endpoint had a lower absolute global longitudinal strain (GLS), a higher post-systolic index (PSI), and more left ventricle walls displaying PSS than patients without events. PSI (hazard ratio, 1.15; 95% CI, 1.04–1.27; p = 0.005) and per 1 increase in the number of left ventricle walls with PSS (hazard ratio 1.52, 95% CI 1.21–1.91, p < 0.000) were independent predictors of the endpoint, whereas GLS was not significantly associated with the endpoint after adjustment models. For patients with absolute value of GLS > 15.4%, a significant prognostic superiority was found in PSI compared with GLS (AUC = 0.73 [PSI] vs. 0.58 [GLS], p = 0.024).

Conclusions

PSS is an independent predictor for adverse events in stable CAD patients with preserved systolic function, and the prognostic value may be superior to GLS in patients with normal or mildly reduced GLS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13244-022-01174-y.

Two-dimensional speckle tracking echocardiography derived post systolic shortening in patients with unstable angina and normal left ventricular systolic function

OBJECTIVES

Post systolic shortening (PSS) had been shown to be sensitive in detecting ischemia on stress echocardiography. This work aims to study the diagnostic potential of resting PSS and post systolic index (PSI) in patients with suspected unstable angina (UA).

METHODS

Total of 159 participants with suspected UA without any wall motion abnormalities were recruited. They all underwent speckle tracking echocardiography (STE) and coronary angiogram (CAG). Global longitudinal strain (GLS), presence or absence of pathological PSS, PSI17 and PSI12, PSI in left anterior descending, left circumflex and right coronary artery territories were assessed. Based on CAG those who had more than 70% stenosis were labelled to have obstructive CAD.

RESULTS

Obstructive disease was noted in 54.7% patients. The prevalence of PSS (62.1% Vs 13.9%), mean PSI17 (5.4 Vs 3.3) and PSI12 (6.2 Vs 3.7) were significantly higher in those with CAD compared to patients without obstructive disease. Both PSS (Odds ratio-10.145; 95% CI, 4.577-22.489; p=0.001) and PSI17 (odds ratio-1.217;95 CI, 1.064-1.393; p=0.004) were predictors of CAD by multivariate regression analysis. PSS had a sensitivity of 62.1% and specificity of 86.1% with a positive predictive value of 84.4%. PSI17 (area under curve- 0.637; p=0.003) and PSI12 (AUC- 0.661; p=0.001) have moderate accuracy in identifying obstructive CAD.

CONCLUSION

In patients presenting with suspected UA, STE derived PSS has reasonable sensitivity and good specificity in diagnosis of obstructive CAD. Patients identified to have PSS can be subjected to CAG without further stress testing because of its high positive predictive value.

Myocardial Work by Echocardiography: Principles and Applications in Clinical Practice

Left ventricular (LV) global longitudinal strain (GLS) has established itself in the last decade as a reliable, more objective method for the evaluation of LV systolic function, able to detect subtle abnormalities in LV contraction even in the presence of preserved ejection fraction (EF). However, recent studies have demonstrated that GLS, similar to LV EF, has important load dependency. Non-invasive myocardial work (MW) quantification has emerged in the last years as an alternative tool for myocardial function assessment. This new method, incorporating measurement of strain and LV pressure, has shown to overcome GLS and LV EF limitations and provide a loading-independent evaluation of myocardial performance. The presence of a commercially available echocardiographic software for the non-invasive MW calculation has allowed the application of this new method in different settings. This review sought to provide an overview on the current knowledge of non-invasive MW estimation, showing its potential applications and possible added value in clinical practice.

Usefulness of Noninvasive Myocardial Work to Predict Left Ventricular Recovery and Acute Complications after Acute Anterior Myocardial Infarction Treated by Percutaneous Coronary Intervention

BACKGROUND

Predicting left ventricular recovery (LVR) after acute ST-elevation myocardial infarction (STEMI) is challenging and of prognostic importance. Our objective was to evaluate the usefulness of noninvasive myocardial work (MW), a new index of global and regional myocardial performance, to predict LVR and in-hospital complications after STEMI.

METHODS

Ninety-three patients with anterior STEMI (mean age, 59 ± 12 years) treated by percutaneous coronary intervention (PCI) were prospectively enrolled and underwent a transthoracic Doppler echocardiography within 24-48 hours after PCI and a median of 92 days at follow-up. Myocardial work is derived from the strain-pressure relation, integrating in its calculation the noninvasive arterial pressure. Segmental LVR was defined as a normalization of wall motion abnormalities of the affected segments and global recovery as an absolute improvement of left ventricular ejection fraction (LVEF) > 5% in patients with baseline LVEF ≤ 50%. In-hospital complications were defined as a composite of death, reinfarction, heart failure, and LV apical thrombus.

RESULTS

Segmental MW was impaired in infarct segments, more severely in nonrecovering versus recovering segments (P < .01). Furthermore, global constructive MW was significantly correlated with follow-up LVEF (r = 0.58) and global longitudinal strain (r = -0.67; all P < .01). Constructive MW was the best index to predict segmental (P < .01 vs MW index, MW efficiency, and wasted work) and global recovery (P < .05 vs global longitudinal strain) with an independent association (odds ratio = 1.17, 95% CI, 1.13-1.20, and odds ratio = 1.43, 95% CI, 1.18-1.68, respectively; all P < .001). Moreover, global constructive MW was more severely impaired in patients with in-hospital complications (n = 16; P < .01).

CONCLUSIONS

In patients with anterior STEMI treated by PCI, constructive MW is an independent predictor of segmental and global LVR and is significantly impaired in patients with in-hospital complications.

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

The concept of paradoxical myocardial deformation, commonly referred to as postsystolic shortening and early systolic lengthening, was originally described in the 1970s when assessed by invasive cardiac methods, such as ventriculograms, in patients with ischemia and animal experimental models. Today, novel tissue-based imaging technology has revealed that these phenomena occur far more frequently than first described. This article defines these deformational patterns, summarizes current knowledge about their existence and highlights the clinical potential associated with their understanding.

Multimodality imaging of myocardial viability: an expert consensus document from the European Association of Cardiovascular Imaging (EACVI)

In clinical decision making, myocardial viability is defined as myocardium in acute or chronic coronary artery disease and other conditions with contractile dysfunction but maintained metabolic and electrical function, having the potential to improve dysfunction upon revascularization or other therapy. Several pathophysiological conditions may coexist to explain this phenomenon. Cardiac imaging may allow identification of myocardial viability through different principles, with the purpose of prediction of therapeutic response and selection for treatment. This expert consensus document reviews current insight into the underlying pathophysiology and available methods for assessing viability. In particular the document reviews contemporary viability imaging techniques, including stress echocardiography, single photon emission computed tomography, positron emission tomography, cardiovascular magnetic resonance, and computed tomography and provides clinical recommendations for how to standardize these methods in terms of acquisition and interpretation. Finally, it presents clinical scenarios where viability assessment is clinically useful.

Incremental prognostic value of global myocardial work over ejection fraction and global longitudinal strain in patients with heart failure and reduced ejection fraction

AIMS

Left ventricular (LV) ejection fraction (EF) and global longitudinal strain (GLS) help identify heart failure (HF) patients who are at risk for adverse outcomes. This study aimed to determine whether global myocardial work (GMW), derived from non-invasive LV pressure-strain loops, can provide incremental prognostic information over EF and GLS in patients with HF and reduced EF (HFrEF).

METHODS AND RESULTS

We retrospectively analysed 508 patients (age 62.9 ± 15.8 years, 29.1% female) with LVEF ≤40%. The study endpoint was a composite of all-cause death and HF hospitalization. The incremental value of GMW over clinical and echocardiographic variables including EF and GLS for the association with the composite endpoint was assessed using Cox regression analyses. Over a 1-year follow-up, 183 patients reached the endpoint. Baseline variables associated with the endpoint were age, haemoglobin, LV end-systolic volume, New York Heart Association Class III or IV, E/e' ratio, pulmonary artery systolic pressure, EF, and GLS. Cox regression analysis revealed that GMW [hazard ratio (HR) 1.15, 95% confidence interval (CI) 1.05-1.25, per 100-mmHg% decrease] added incremental prognostic value over these variables. Both EF and GLS were not independent variables when GMW was included in the model. Patients with GMW <750 mmHg% were associated with a significantly higher risk of all-cause death and HF hospitalization (HR 3.33, 95% CI 2.31-4.80) than patients with GMW ≥750 mmHg%.

CONCLUSION

In patients with HFrEF, GMW provides incremental prognostic information over EF and GLS regarding risk of all-cause death and HF hospitalization.

Prognostic Value of Phase Analysis for Predicting Adverse Cardiac Events Beyond Conventional Single-Photon Emission Computed Tomography Variables: Results From the REFINE SPECT Registry

BACKGROUND

Phase analysis of single-photon emission computed tomography myocardial perfusion imaging provides dyssynchrony information which correlates well with assessments by echocardiography, but the independent prognostic significance is not well defined. This study assessed the independent prognostic value of single-photon emission computed tomography-myocardial perfusion imaging phase analysis in the largest multinational registry to date across all modalities.

METHODS

From the REFINE SPECT (Registry of Fast Myocardial Perfusion Imaging With Next Generation SPECT), a total of 19 210 patients were included (mean age 63.8±12.0 years and 56% males). Poststress total perfusion deficit, left ventricular ejection fraction, and phase variables (phase entropy, bandwidth, and SD) were obtained automatically. Cox proportional hazards analyses were performed to assess associations with major adverse cardiac events (MACE).

RESULTS

During a follow-up of 4.5±1.7 years, 2673 (13.9%) patients experienced MACE. Annualized MACE rates increased with phase variables and were ≈4-fold higher between the second and highest decile group for entropy (1.7% versus 6.7%). Optimal phase variable cutoff values stratified MACE risk in patients with normal and abnormal total perfusion deficit and left ventricular ejection fraction. Only entropy was independently associated with MACE. The addition of phase entropy significantly improved the discriminatory power for MACE prediction when added to the model with total perfusion deficit and left ventricular ejection fraction (P<0.0001).

CONCLUSIONS

In a largest to date imaging study, widely representative, international cohort, phase variables were independently associated with MACE and improved risk stratification for MACE beyond the prediction by perfusion and left ventricular ejection fraction assessment alone. Phase analysis can be obtained fully automatically, without additional radiation exposure or cost to improve MACE risk prediction and, therefore, should be routinely reported for single-photon emission computed tomography-myocardial perfusion imaging studies.

Myocardial Work, an Echocardiographic Measure of Post Myocardial Infarct Scar on Contrast-Enhanced Cardiac Magnetic Resonance

This study investigates the relation of non-invasive myocardial work and myocardial viability following ST-segment elevation myocardial infarction (STEMI) assessed on late gadolinium contrast enhanced cardiac magnetic resonance (LGE CMR) and characterizes the remote zone using non-invasive myocardial work parameters. STEMI patients who underwent primary percutaneous coronary intervention (PCI) were included. Several non-invasive myocardial work parameters were derived from speckle tracking strain echocardiography and sphygmomanometric blood pressure, e.g.: myocardial work index (MWI), constructive work (CW), wasted work (WW) and myocardial work efficiency (MWE). LGE was quantified to determine infarct transmurality and scar burden. The core zone was defined as the segment with the largest extent of transmural LGE and the remote zone as the diametrically opposed segment without LGE. A total of 53 patients (89% male, mean age 58 ± 9 years) and 689 segments were analyzed. The mean scar burden was 14 ± 7% of the total LV mass, and 76 segments (11%) demonstrated transmural hyperenhancement, 280 (41%) non-transmural hyperenhancement and 333 (48%) no LGE. An inverse relation was observed between segmental MWI, CW and MWE and infarct transmurality (p < 0.05). MWI, CW and MWE were significantly lower in the core zone compared to the remote zone (p<0.05). In conclusion, non-invasive myocardial work parameters may serve as potential markers of segmental myocardial viability in post-STEMI patients who underwent primary PCI. Non-invasive myocardial work can also be utilized to characterize the remote zone, which is an emerging prognostic marker as well as a therapeutic target.

The non-invasive assessment of myocardial work by pressure-strain analysis: clinical applications

Pressure–volume (PV) analysis is the most comprehensive way to describe cardiac function, giving insights into cardiac mechanics and energetics. However, PV analysis still remains a highly invasive and time-consuming method, preventing it from integration into clinical practice. Most of the echocardiographic parameters currently used in the clinical routine to characterize left ventricular (LV) systolic function, such as LV ejection fraction and LV global longitudinal strain, do not take the pressure developed within the LV into account and therefore fall too short in describing LV function as a hydraulic pump. Recently, LV pressure-strain analysis has been introduced as a new technique to assess myocardial work in a non-invasive fashion. This new method showed new insights in comparison to invasive measurements and was validated in different cardiac pathologies, e.g., for the detection of coronary artery disease, cardiac resynchronization therapy (CRT)-response prediction, and different forms of heart failure. Non-invasively assessed myocardial work may play a major role in guiding therapies and estimating prognosis. However, its incremental prognostic validity in comparison to common echocardiographic parameters remains unclear. This review aims to provide an overview of pressure-strain analysis, including its current application in the clinical arena, as well as potential fields of exploitation.

The prognostic value of myocardial deformational patterns on all-cause mortality is modified by ischemic cardiomyopathy in patients with heart failure

Early systolic lengthening and postsystolic shortening may yield prognostic information in cardiovascular high-risk groups. We aimed to investigate the prognostic potential of these patterns in patients with heart failure with reduced ejection fraction (HFrEF), and specifically if the value was greater in patients with ischemic etiology. A total of 884 patients with HFrEF (66 ± 12 years, male 73%, mean EF 28 ± 9%) underwent speckle tracking echocardiography. Of these, 61% suffered from ischemic cardiomyopathy (ICM). Patients were followed for all-cause mortality. We assessed myocardial lengthening during early systole, defined by the early systolic strain index (ESI): [-100x (peak positive strain/maximal strain)] and myocardial shortening after aortic valve closure, defined by the postsystolic strain index (PSI): [100x (postsystolic strain-peak systolic strain)/maximal strain]. During median follow-up of 3.4 [interquartile range 1.9 to 4.8] years, 132 patients (15%) died. ICM modified the relationship between ESI and all-cause mortality (P interaction = 0.008), but not for PSI (P interaction = 0.13). When assessing patients with ICM by Cox proportional hazards models, per 1% increase in ESI (HR 1.09 [1.04 to 1.15], P < 0.001) and PSI (HR 1.02 [1.01 to 1.03], P = 0.002) were associated with all-cause mortality. However, in multivariable models adjusted for clinical, invasive and echocardiographic information, only ESI was a predictor of the endpoint (HR 1.07 [1.00 to 1.13], P = 0.023). In patients with no ICM, neither ESI (HR 0.99 per 1% increase [0.90 to 1.09], P = 0.86) nor PSI (HR 1.00 per 1% increase [0.99 to 1.02], P = 0.88) were associated with all-cause mortality. Our results indicate that in HFrEF patients with ischemic etiology, the ESI may provide some information on prognosis, whereas the prognostic value of PSI is reduced. In patients with HFrEF and no prior exposure to ischemia, the prognostic value of both deformational patterns is reduced.

Resting global myocardial work can improve interpretation of exercise stress echocardiography

Sensitivity and specificity of ESE to determine hemodynamically significant coronary artery disease (CAD) is limited by subjective qualitative interpretation resulting in false-positive results. The objective of this study was to determine whether resting myocardial work estimated from non-invasive left ventricular pressure-strain loops can help improve the interpretation of exercise stress echocardiography (ESE). Resting global myocardial work was performed on 288 patients referred for clinically indicated ESE with no resting regional wall motion abnormalities and normal ejection fraction (≥ 55%). Coronary angiography was used to validate the presence of significant CAD in those with a positive ESE. Resting global myocardial work index (GWI) was significantly reduced (p < 0.001) in patients with true-positive (1544 ± 354 mmHg%) compared to negative (1819 ± 317 mmHg%) and false-positive (1857 ± 344 mmHg%) ESE. A GWI of ≤ 1391 mmHg (AUC 0.73; sensitivity 94%; specificity 73%) predicted true-positive ESE. Predictors of a true-positive ESE were (1) lower myocardial work efficiency (odds ratio 0.731, 95% CI 0.58-0.92, p = 0.007), (2) lower GWI (odds ratio 0.997, 95% CI 0.996-0.999, p = 0.006) (3) male gender (odds ratio 5.47, 95% CI 1.84-16.31, p = 0.002) and (4) E/e' ratio (odds ratio 1.15, CI 1.01-1.31, p = 0.032). Myocardial work is a potentially valuable quantitative parameter that provides incremental value over qualitative ESE interpretation and improves appropriate patient selection for coronary angiography.

Rapidly and Accurately Detecting Significant Coronary Artery Stenosis in Patients with Suspected Stable Coronary Artery Disease and Normal Segmental Wall Motion by Speckle Tracking Automated Functional Imaging

This study was performed to explore the value of a machine with built-in speckle tracking automated functional imaging (AFI) in predicting the severity of coronary artery lesions in patients with suspected stable coronary artery disease (SCAD) with normal wall motion. One hundred forty-three consecutive patients with clinically suspected SCAD with normal wall motion were included. Multiple parameters, including global longitudinal peak strain, post-systolic index (PSI) and peak strain dispersion, were automatically analyzed with AFI. Territorial longitudinal strain (TLS) and territorial PSI (TPSI) were also calculated. Receiver operating characteristic curve analyses revealed that global longitudinal peak strain and PSI were superior to other parameters in detecting left main or three-vessel SCAD. A combination of TLS and TPSI could improve diagnostic performance in identifying significant stenotic left anterior descending and right coronary arteries. In conclusion, 2-dimensional speckle tracking AFI can rapidly provide multiple parameters for detecting significant coronary artery stenosis with high accuracy in patients suspected of having SCAD with normal wall motion.

Clinical Utility of Echocardiographic Strain and Strain Rate Measurements

PURPOSE OF REVIEW

Assessment of left ventricular function is pivotal in many decisions, but ejection fraction has fundamental limitations for assessment of mild dysfunction, and especially for repeated assessments. Myocardial deformation imaging using speckle-tracking is widely available on modern echocardiography systems, and is now feasible as a clinical, rather than purely a research tool. Strain can be measured in all cardiac chambers, most commonly as a systolic parameter, although it can be measured in diastole. Generally, speckle tracking is more effective at measuring strain than strain-rate, which requires a higher temporal resolution. The purpose of this review is to help clinicians understand the main situations where strain provides incremental value to standard echocardiographic measurements.

RECENT FINDINGS

The normal range of LV global longitudinal strain (GLS) has now been defined as -18% and lower (ie more negative), abnormal as -16% or higher (ie less negative), with -16 to -18% being borderline. The variation between different vendors is now small for global parameters, but regional strain measurement remains unreliable - and therefore its use for stress echocardiography remains problematic. The most valuable indications for measuring strain are subclinical LV dysfunction (eg., GLS in HFpEF, stage B heart failure, aortic stenosis, mitral regurgitation), RV dysfunction (RV strain in pulmonary hypertension), atrial fibrillation (LA strain) and sequential follow-up (cardiotoxicity). Strain measurements have clinical utility in a number of settings and should be considered as part of the standard echocardiogram.

[Echocardiography in the Assessment of Postsystolic Shortening of the Left Ventricle Myocardium of the Heart]

Echocardiography allows evaluating left ventricular (LV) myocardial contractility; however, the visual assessment of contractility is subjective and requires considerable experience. Modern technologies for assessment of LV myocardial contractility, such as tissue Doppler and speckle-tracking echocardiography, provide quantitative estimation of various parameters of myocardial strain, including the LV postsystolic shortening. Several studies have demonstrated the value of postsystolic shortening for evaluation of myocardial ischemia and "ischemic memory" in patients with cardiovascular diseases. This review analyzes experimental and clinical studies that addressed LV postsystolic shortening.

Asymmetric Regional Work Contributes to Right Ventricular Fibrosis, Inefficiency, and Dysfunction in Pulmonary Hypertension versus Regurgitation

BACKGROUND

Right ventricular (RV) pressure loading from pulmonary hypertension (PH) and volume loading from pulmonary regurgitation (PR) lead to RV dysfunction, a critical determinant of clinical outcomes, but their impact on regional RV mechanics and fibrosis is poorly characterized. The aim of this study was to test the hypothesis that regional myocardial mechanics and efficiency in RV pressure and volume loading are associated with RV fibrosis and dysfunction.

METHODS

Eight PH, six PR, and five sham-control rats were studied. The PH rat model was induced using Sugen5416, a vascular endothelial growth factor receptor 2 inhibitor, combined with chronic hypoxia. PR rats were established by surgical laceration of the pulmonary valve leaflets. Six (n = 4) or 9 (n = 4) weeks after Sugen5416 and hypoxia and 12 weeks after PR surgery, myocardial strain and RV pressure were measured and RV pressure-strain loops generated. We further studied RV regional mechanics in 11 patients with PH. Regional myocardial work was calculated as the pressure-strain loop area (mm Hg ∙ %). Regional myocardial work efficiency was quantified through wasted work (ratio of systolic lengthening to shortening work). The relation of regional myocardial work to RV fibrosis and dysfunction was analyzed.

RESULTS

In rats, PH and PR induced similar RV dilatation, but fractional area change (%) was lower in PH than in PR. RV lateral wall work was asymmetrically higher in PH compared with sham, while septal work was similar to sham. In PR, lateral and septal work were symmetrically higher versus sham. Myocardial wasted work ratio was asymmetrically increased in the PH septum versus sham. Fibrosis in the RV lateral wall, but not septum, was higher in PH than PR. RV fibrosis burden was linearly related to regional work and to measures of RV systolic and diastolic function but not to wasted myocardial work ratio. Patients with PH demonstrated similar asymmetric and inefficient regional myocardial mechanics.

CONCLUSIONS

Asymmetric RV work and increased wasted septal work in experimental PH are associated with RV fibrosis and dysfunction. Future investigation should examine whether assessment of asymmetric regional RV work and efficiency can predict clinical RV failure and influence patient management.

Value of territorial work efficiency estimation in non-ST-segment-elevation acute coronary syndrome: a study with non-invasive left ventricular pressure-strain loops

Non-ST-segment-elevation acute coronary syndrome (NSTE-ACS) patients with normal left ventricular (LV) ejection fraction (LVEF) and wall motion require a non-invasive tool to detect LV risk areas. This study utilized non-invasive LV pressure-strain loops to evaluate territorial myocardial work efficiency (WE) for identifying obstructive coronary artery stenosis, in patients with non-obstructive or obstructive coronary artery stenosis NSTE-ACS, the latter with or without occlusion. Global and territorial longitudinal strain (LS) analyses were performed via speckle-tracking imaging before coronary angiography. LV pressure-strain loops estimated global and territorial myocardial work index (MWI), constructive work (CW), wasted work (WW), and WE. Receiver operating characteristic curve analysis was used to determine the optimal cutoff value of independent parameters to detect obstructive coronary artery stenosis. Compared with non-obstructive, obstructive coronary artery stenosis showed significantly lower global and territorial LS, MWI, CW, and WE, and higher WW. Territorial LS, MWI, CW, and WE were significantly worse in territories of coronary occlusion. Territorial WE was the best parameter for predicting obstructive coronary artery stenosis (AUC 0.80, cutoff < 96%, sensitivity 73%, specificity 70%, P < 0.001). In patients with NSTE-ACS with normal wall motion and LVEF, territorial WE is more accurate than territorial LS or MWI to identify LV risk areas.

Automatic detection of valve events by epicardial accelerometer allows estimation of the left ventricular pressure trace and pressure-displacement loop area

Measurements of the left ventricular (LV) pressure trace are rarely performed despite high clinical interest. We estimated the LV pressure trace for an individual heart by scaling the isovolumic, ejection and filling phases of a normalized, averaged LV pressure trace to the time-points of opening and closing of the aortic and mitral valves detected in the individual heart. We developed a signal processing algorithm that automatically detected the time-points of these valve events from the motion signal of a miniaturized accelerometer attached to the heart surface. Furthermore, the pressure trace was used in combination with measured displacement from the accelerometer to calculate the pressure–displacement loop area. The method was tested on data from 34 animals during different interventions. The accuracy of the accelerometer-detected valve events was very good with a median difference of 2 ms compared to valve events defined from hemodynamic reference recordings acquired simultaneously with the accelerometer. The average correlation coefficient between the estimated and measured LV pressure traces was r = 0.98. Finally, the LV pressure–displacement loop areas calculated using the estimated and measured pressure traces showed very good correlation (r = 0.98). Hence, the pressure–displacement loop area can be assessed solely from accelerometer recordings with very good accuracy.

The combined effects of cardiac geometry, microcirculation, and tissue characteristics on cardiac systolic and diastolic function in subclinical diabetes mellitus-related cardiomyopathy

BACKGROUND

Diabetes mellitus-related cardiomyopathy has recently been described as a distinct progression of left ventricular (LV) systolic and diastolic dysfunction. Pathological changes in the myocardium may explain the development of two different phenotypes. We evaluated the effects of LV geometry, myocardial microcirculation, and tissue characteristics on cardiac deformation in patients with subclinical type 2 diabetes mellitus (T2DM) utilizing multiparametric cardiac magnetic resonance (CMR) imaging.

METHODS

A total of 135 T2DM patients and 55 matched controls were prospectively enrolled and performed multiparametric CMR examination. CMR-derived parameters including cardiac geometry, function, microvascular perfusion, T1 mapping, T2 mapping, and strain were analyzed and compared between T2DM patients and controls.

RESULTS

The univariable and multivariable analysis of systolic and diastolic function revealed that longer duration of diabetes was associated with decreased longitudinal peak systolic strain rate (PSSR-L) (β = 0.195, p = .013), and higher remodeling index and higher extracellular volume (ECV) tended to correlate with decreased longitudinal peak diastolic strain rate (PDSR-L) (remodeling index, β = -0.339, p = .000; ECV, β = -0.172, p = .026), whereas microvascular perfusion index and T2 value affected both PSSR-L (perfusion index, β = -0.328, p = .000; T2 value, β = 0.306, p = .000) and PDSR-L (perfusion index, β = 0.209, p = .004; T2 value, β = -0.275, p = .000) simultaneously.

CONCLUSIONS

The LV concentric remodeling and myocardial fibrosis correlated with diastolic function, and perfusion function and myocardial edema were associated with both LV systolic and diastolic function.

2- and 3-Dimensional Myocardial Strain in Cardiac Health and Disease

Advances in speckle-tracking echocardiography allowed the rise of deformation imaging as a feasible, robust, and valuable tool for clinical routine. The global or segmental measurement of strain can objectively quantify myocardial deformation and can characterize myocardial function in a novel way. However, the proper interpretation of deformation measurements requires understanding of cardiac mechanics and the influence of loading conditions, ventricular geometry, conduction delays, and myocardial tissue characteristics on the measured values. The purpose of this manuscript is to review the basic concepts of deformation imaging, briefly describe imaging modalities for strain assessment, and discuss in depth the underlying physical and pathophysiological mechanisms which lead to the respective findings in a specific disease.

Clinical significance of early-diastolic tissue velocity imaging of lateral mitral annulus for prognosis of nonischemic left ventricular dysfunction

PURPOSE

We explored the potential of tissue velocity imaging (TVI) for prognosis of nonischemic left ventricular (LV) dysfunction (LVD).

METHODS

We reviewed 138 nonischemic LVD patients (58 ± 14 years) who underwent both cardiac magnetic resonance (CMR) and echocardiography. Septal and lateral mitral annular TVI data were compared with late gadolinium enhancement (LGE) on CMR. During a mean follow-up of 24 months, recovery (>15%) of LV ejection fraction and clinical outcomes (cardiovascular death and heart failure hospitalization) were assessed.

RESULTS

LGE was commonly observed in the basal anteroseptal, inferoseptal, and inferior segments, but infrequently observed in the anterolateral segment. LGE was associated with lower early diastolic, septal (Sep-e' = 5.2 ± 2.0 vs 6.9 ± 2.0 cm/s, P = .031) and lateral (Lat-e' = 7.3 ± 3.0 vs 9.5 ± 2.0 cm/s, P < .001) TVI. The relationship between Lat-e' and anterolateral LGE (area under the curve, AUC 0.834) was much better than that between Sep-e' and inferoseptal LGE (AUC 0.699). The 60 patients with LVD reversibility revealed higher Lat-e' (9.8 ± 2.0 vs 6.7 ± 2.2 cm/s, P < .001) and lower LGE burden (7.3 ± 9.0 vs 22 ± 10%, P < .001), while Lat-e' ≤ 7.8 cm/s appeared unfavorable for 31 events patients. On multivariate analyses, Lat-e' (HR 0.79, 95% CI 0.63-0.99, P = .044) and LVD reversibility (HR 0.53, 95% CI 0.16-0.90, P = .018) were still meaningful together with LGE segments and burden.

CONCLUSION

Lat-e' was related with LVD reversibility and a significant predictor of clinical outcomes.

Regional myocardial strain analysis via 2D speckle tracking echocardiography: validation with sonomicrometry and correlation with regional blood flow in the presence of graded coronary stenoses and dobutamine stress

Background

Quantitative regional strain analysis by speckle tracking echocardiography (STE) may be particularly useful in the assessment of myocardial ischemia and viability, although reliable measurement of regional strain remains challenging, especially in the circumferential and radial directions. We present an acute canine model that integrates a complex sonomicrometer array with microsphere blood flow measurements to evaluate regional myocardial strain and flow in the setting of graded coronary stenoses and dobutamine stress. We apply this unique model to rigorously evaluate a commercial 2D STE software package and explore fundamental regional myocardial flow-function relationships.

Methods

Sonomicrometers (16 crystals) were implanted in epicardial and endocardial pairs across the anterior myocardium of anesthetized open chest dogs (n = 7) to form three adjacent cubes representing the ischemic, border, and remote regions, as defined by their relative locations to a hydraulic occluder on the mid-left anterior descending coronary artery (LAD). Additional cardiac (n = 3) and extra-cardiac (n = 3) reference crystals were placed to define the cardiac axes and aid image registration. 2D short axis echocardiograms, sonometric data, and microsphere blood flow data were acquired at baseline and in the presence of mild and moderate LAD stenoses, both before and during low-dose dobutamine stress (5 μg/kg/min). Regional end-systolic 2D STE radial and circumferential strains were calculated with commercial software (EchoInsight) and compared to those determined by sonomicrometry and to microsphere blood flow measurements. Post-systolic indices (PSIs) were also calculated for radial and circumferential strains.

Results

Low-dose dobutamine augmented both strain and flow in the presence of mild and moderate stenoses. Regional 2D STE strains correlated moderately with strains assessed by sonomicrometry (R_radial = 0.56, p < 0.0001; R_circ = 0.55, p < 0.0001) and with regional flow quantities (R_radial = 0.61, R_circ = 0.63). Overall, correspondence between 2D STE and sonomicrometry was better in the circumferential direction (Bias ± 1.96 SD: − 1.0 ± 8.2% strain, p = 0.06) than the radial direction (5.7 ± 18.3%, p < 0.0001). Mean PSI values were greatest in low flow conditions and normalized with low-dose dobutamine.

Conclusions

2D STE identifies changes in regional end-systolic circumferential and radial strain produced by mild and moderate coronary stenoses and low-dose dobutamine stress. Regional 2D STE end-systolic strain measurements correlate modestly with regional sonomicrometer strain and microsphere flow measurements.

Postsystolic shortening on echocardiography as a gateway to cardiac computed tomography in patients with suspected stable angina pectoris

Postsystolic shortening (PSS) by speckle-tracking echocardiography (STE) is a marker of myocardial ischemia and may improve diagnostic strategy. We sought to evaluate if PSS is associated with the coronary artery calcium score (CACS) and stenosis by computed tomography angiography (CTA) in patients with suspected stable angina pectoris (SAP). We retrospectively studied 437 SAP patients (age 58 ± 11 years, 41% male) who underwent STE, evaluation of CACS and assessment of significant stenosis (≥ 50%) by CTA. The postsystolic index (PSI) was defined as follows: 100x([peak negative strain cardiac cycle - peak negative strain systole])/peak negative strain cardiac cycle. A wall had PSS if any segment within the wall had a PSI ≥ 20%. We defined categories for walls with PSS: 0, 1, 2 and ≥ 3, and CACS: 0, 1-100, 101-400 and > 400. Each additional wall with PSS was associated with a 43% relative increase in CACS (95%CI +9% to +87%, P = 0.010), while each 1% absolute increase in the PSI was associated with a 9% relative increase in CACS (95%CI +1% to +18%, P = 0.031). Walls with PSS (OR 1.81 per 1 wall increase, 95%CI 1.27-2.59, P = 0.001) and the PSI (OR 1.12 per 1% increase, 95%CI 1.04-1.21, P = 0.004) were associated with the occurrence of CACS > 400. Additionally, walls with PSS (OR 1.53 per 1 wall increase, 95%CI 1.21-1.93, P < 0.001) was a predictor of significant stenosis by CTA. PSS is associated with CACS and significant stenosis by CTA in patients with SAP and may aid in the selection of patients referred for cardiac computed tomography.

Stress echocardiography in coronary artery disease: a practical guideline from the British Society of Echocardiography

Stress echocardiography is an established technique for assessing coronary artery disease. It has primarily been used for the diagnosis and assessment of patients presenting with chest pain in whom there is an intermediate probability of coronary artery disease. In addition, it is used for risk stratification and to guide revascularisation in patients with known ischaemic heart disease. Although cardiac computed tomography has recently been recommended in the United Kingdom as the first-line investigation in patients presenting for the first time with atypical or typical angina, stress echocardiography continues to have an important role in the assessment of patients with lesions of uncertain functional significance and patients with known ischaemic heart disease who represent with chest pain. In this guideline from the British Society of Echocardiography, the indications and recommended protocols are outlined for the assessment of ischaemic heart disease by stress echocardiography.

Post-systolic shortening predicts heart failure following acute coronary syndrome

BACKGROUND

Post-systolic shortening (PSS) is a novel echocardiographic marker of myocardial dysfunction. Our objective was to assess the prognostic value of PSS in patients following acute coronary syndrome (ACS) who underwent percutaneous coronary intervention (PCI).

METHODS

A total of 428 patients hospitalized for ACS (mean age 64 ± 12 years, male 73%) underwent speckle tracking echocardiography following treatment with PCI (median 2 days). The individual endpoints were heart failure (HF), myocardial infarction (MI) and all-cause death. We excluded known HF. Presence of PSS was defined as post-systolic displacement ≥20% of maximum strain in one cardiac cycle. The post-systolic index (PSI) was defined as (100 × [maximum-strain cardiac cycle - peak-systolic strain])/(maximum-strain cardiac cycle)].

RESULTS

During median follow-up of 3.7 years (IQR 0.3, 5.2), 155 patients (36%) experienced HF, 52 (12%) had MI and 87 (20%) died from all causes. Patients experiencing HF had more walls displaying PSS (3.2 vs. 1.9 walls) and higher PSI (22% vs. 12%) (P < 0.001 both). In Cox proportional hazards models adjusted for baseline characteristics, invasive and echocardiographic measurements, the risk of HF increased incrementally with increasing number of walls with PSS (HR 1.28 95%CI 1.12-1.46, P < 0.001 per 1 increase in walls with PSS). The PSI remained an independent predictor of HF after adjustment (HR 1.61 95%CI 1.21-2.12, P = 0.001 per 1% increase). In the same adjusted models, MI and all-cause death were not significantly associated with PSS.

CONCLUSION

Presence of PSS provides novel and independent prognostic information regarding the risk of future HF in patients with ACS following PCI.

Phase analysis single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) detects dyssynchrony in myocardial scar and increases specificity of MPI

BACKGROUND

Myocardial perfusion imaging (MPI) with single-photon emission computed tomography (SPECT) is commonly used to assess patients with cardiovascular disease. However, in certain scenarios, it may have limited specificity in the identification of hemodynamically significant coronary artery disease (e.g., false positive), potentially resulting in additional unnecessary testing and treatment. Phase analysis (PA) is an emerging, highly reproducible quantitative technology that can differentiate normal myocardial activation (synchrony) from myocardial scar (dyssynchrony). The objective of this study is to determine if PA can improve the specificity SPECT MPI.

METHODS

An initial cohort of 340 patients (derivation cohort), referred for SPECT-MPI, was prospectively enrolled. Resting MPI studies were assessed for resting perfusion defects (scar). These were utilized as the reference standard for scar. Subsequently, we collected a second independent validation cohort of 138 patients and tested the potential of PA to reclassify patients for the diagnosis of "scar" or "no scar." Patients were assigned to three categories depending upon their pre-test probability of scar based on multiple clinical and imaging parameters: ≤ 10% (no scar), 11-74% (indeterminate), and ≥ 75% (scar). The ability of PA variables to reclassify patients with scar to a higher group and those without scar to a lower group was then determined using the net reclassification index (NRI).

RESULTS

Entropy (≥ 59%) was independently associated with scar in both patient cohorts with an odds ratio greater than five. Furthermore, when added to multiple clinical/imaging variables, the use of entropy significantly improved the area under the curve for assessment of scar (0.67 vs. 0.59, p = 0.04). The use of entropy correctly reclassified 24% of patients without scar, by clinical model, to a lower risk category (as determined by pre-test probability) with an overall NRI of 18% in this validation cohort.

DISCUSSION

The use of PA entropy can improve the specificity of SPECT MPI and may serve as a useful adjunctive tool to the interpreting physician. The current study determined the optimal PA parameters to detect scar (derivation cohort) and applied these parameters to a second, independent, patient group and noted that entropy (≥ 59%) was independently associated with scar in both patient cohorts. Therefore, PA, which requires no additional imaging time or radiation, enhances the diagnostic capabilities of SPECT MPI.

CONCLUSION

The use of PA entropy significantly improved the specificity of SPECT MPI and could influence the labeling of a patient as having or not having myocardial scar and thereby may influence not only diagnostic reporting but also potentially prognostic determination and therapeutic decision-making.

Speckle tracking echocardiography analyses of myocardial contraction efficiency predict response for cardiac resynchronization therapy

BACKGROUND

In patients with left ventricular (LV) dysssynchrony, contraction that doesn't fall into ejection period (LVEj) results in a waste of energy due to inappropriate contraction timing, which was now widely treated by cardiac resynchronization therapy(CRT). Myocardial Contraction Efficiency was defined as the ratio of Efficient Contraction Time (ECTR) and amplitude of efficient contraction (ECR) during LVEj against that in the entire cardiac cycle. This study prospectively investigated whether efficiency indexes could predict CRT outcome.

METHODS

Our prospective pilot study including 70 CRT candidates, parameters of myocardial contraction timing and contractility were measured by speckle tracking echocardiography (STE) and efficiency indexes were calculated accordingly at baseline and at 6-month follow-up. Primary outcome events were predefined as death or HF hospitalization, and secondary outcome events were defined as all-cause death during the follow-up. 16-segement Standard deviation of time to onset strain (TTO-16SD) and time to peak strain (TTP-16SD) were included as the dyssynchrony indexes.

RESULTS

According to LV end systolic volume (LVESV) and LV eject fraction(LVEF) values at 6-month follow-up, subjects were classified into responder and non-responder groups, ECR (OR 0.87, 95%CI 0.78-0.97, P < 0.05) and maximum longitudinal strain (MLS) (OR 2.22, 95%CI 1.36-3.61, P < 0.01) were the two independent predictors for CRT response, Both TTO-16SD and TTP-16SD failed to predict outcome. Patients with poorer myocardial contraction efficiency and better contractility are more likely to benefit from CRT.

CONCLUSIONS

STE can evaluate left ventricular contraction efficiency and contractility to predict CRT response. When analyzing myocardial strain by STE, contraction during LVEj should be highlighted.

Post-systolic shortening: normal values and association with validated echocardiographic and invasive measures of cardiac function

Post-systolic shortening (PSS) does not contribute to the ejection of blood and may inhibit diastolic filling. We determined normal values of PSS in healthy subjects and investigated associations with echocardiographic and invasive measures of systolic and diastolic function. We prospectively analyzed participants from the general population (n = 620, mean age 47 ± 14 years) with no cardiovascular disease. Participants underwent echocardiography, including speckle tracking assessment of the post-systolic index (PSI), strain and time. We defined the PSI as: 100 × [(peak global longitudinal strain - peak systolic longitudinal strain)/(peak global longitudinal strain)]. We also included stable patients (n = 44) referred for left ventricle (LV) catheterization and echocardiography. Normal values: median PSI 2.0% (IQR 0.7, 4.8), post-systolic strain 0.4% (IQR 0.2, 0.8) and post-systolic time 22.6 ms (IQR 10.7, 40.8). Sex modified the relationship between PSI and age (P interaction = 0.037), such that PSI increased with age in women but not in men. PSI was associated with diastolic function (e', E/e' and E/A) (P < 0.05 for all), but not with LV ejection fraction (P = 0.08). PSI was associated with invasively measured LV pressure decline in early diastole, dP/dt min ([Formula: see text] = 0.12, P = 0.010), but not with LV pressure rise in early systole, dP/dt max ([Formula: see text]= - 0.05, P = 0.30). A PSI > 5% had 82% specificity and 99% sensitivity for identifying impaired LV systolic and/or diastolic function. Normal values of PSS are modified by sex. The PSI is associated with most validated echocardiographic and invasive measures of cardiac systolic and diastolic function.

Postsystolic Shortening by Speckle Tracking Echocardiography Is an Independent Predictor of Cardiovascular Events and Mortality in the General Population

Background

Postsystolic shortening (PSS) has been proposed as a novel marker of contractile dysfunction in the myocardium. Our objective was to assess the prognostic potential of PSS on cardiovascular events and death in the general population.

Methods and Results

The study design consisted of a prospective cohort study of 1296 low‐risk participants from the general population, who were examined by speckle tracking echocardiography. The primary end point was the composite of heart failure, myocardial infarction, and cardiovascular death, defined as major adverse cardiovascular events (MACEs). The secondary end point was all‐cause death. The postsystolic index (PSI) was defined as follows: [(maximum strain in cardiac cycle−peak systolic strain)/(maximum strain in cardiac cycle)]×100. PSS was regarded as present if PSI >20%. During a median follow‐up of 11 years, 149 participants (12%) were diagnosed as having MACEs and 236 participants (18%) died. Increasing number of walls with PSS predicted both end points, an association that persisted after adjustment for age, sex, estimated glomerular filtration rate, global longitudinal strain, hypertension, heart rate, left ventricular ejection fraction, LV mass index, pro‐B‐type natriuretic peptide, previous ischemic heart disease, systolic blood pressure, average peak early diastolic longitudinal mitral annular velocity (e′), ratio between peak transmitral early and late diastolic inflow velocity (E/A), and left atrial volume index: MACEs (hazard ratio, 1.35; 95% confidence interval, 1.09–1.67; P=0.006 per 1 increase in walls displaying PSS) and death (hazard ratio, 1.30; 95% confidence interval, 1.08–1.57; P=0.006 per 1 increase in walls displaying PSS). The strongest predictor of end points was ≥2 walls exhibiting PSS. The PSI also predicted increased risk of the end points, and the associations remained significant in multivariable models: MACEs (per 1% increase in PSI: hazard ratio, 1.18; 95% confidence interval, 1.02–1.36; P=0.024) and death (per 1% increase in PSI: hazard ratio, 1.18; 95% confidence interval, 1.05–1.33; P=0.005).

Conclusions

Presence of PSS in the general population provides independent and long‐term prognostic information on the occurrence of MACEs and death.

Presence of post-systolic shortening is an independent predictor of heart failure in patients following ST-segment elevation myocardial infarction

Following an ischemic event post systolic shortening (PSS) may occur. We investigated the association between PSS in patients with ST-segment elevation myocardial infarction (STEMI) following primary percutaneous coronary intervention (pPCI) and occurrence of cardiovascular events at follow-up. A total of 373 patients admitted with STEMI and treated with pPCI were prospectively included in the study cohort. All patients were examined by echocardiography a median of 2 days after admission (interquartile range, 1-3 days). PSS was measured by color tissue Doppler imaging (TDI) and speckle tracking echocardiography (STE) in six myocardial walls from all three apical projections. During a median follow-up period of 5.4 years (interquartile range, 4.1-6.0 years), 180 events occurred: 59 deaths, 70 heart failures (HF) and 51 new myocardial infarctions (MI). In multivariable analysis adjusting for: age, sex, peak troponin, left ventricle ejection fraction, TIMI flow grade, left ventricle mass index, hypertension and diabetes, presence of PSS by TDI in the culprit region was associated with a nearly twofold increased risk of HF (HR 1.90, 95% CI 1.02-3.53, P = 0.043) and the risk of HF increased incrementally with increasing numbers of walls displaying PSS. The increased risk of HF was confirmed when assessing the post-systolic index by STE (HR 1.29 95% CI 1.09-1.53, P = 0.003, per 1% increase). A regional analysis showed that PSS by TDI in the septal wall was the strongest predictor of HF (HR 1.77, 95% CI 1.08-2.92, P = 0.024). Presence of PSS was not associated with increased risk of death or MI. In patients with STEMI treated with pPCI, the presence of PSS examined by TDI and STE provides prognostic information on development of HF. Presence of PSS in the septal wall is the strongest predictor of HF.

Global longitudinal strain from resting echocardiogram is associated with long-term adverse cardiac outcomes in patients with suspected coronary artery disease

Purpose:

Measuring myocardial strain using two-dimensional speckle tracking echocardiography has emerged as a new tool to identify subclinical ventricular dysfunction. Abnormal strain has been shown to have superior sensitivity compared with dobutamine stress echocardiography for viability assessment; however, there is a paucity of data regarding the prediction of long-term major adverse cardiac events. We compared the prognostic ability of both global longitudinal strain (GLS) from resting echocardiograms to regional wall motion score index (WMSI) from stress echocardiograms in their ability to predict long-term major adverse cardiac events.

Methods:

Patients referred for stress echocardiography, who also underwent coronary angiography within 3 months of stress echo (n=122), were enrolled. Patients with reduced ejection fractions (<40%) were excluded. Patients were followed for a median of 3.4 years for major adverse cardiac events, readmissions and repeat cardiac testing.

Results:

Patients with abnormal GLS (GLS <16.8%) from the resting echocardiogram obtained as part of the exercise echocardiogram experienced a significantly shorter time to major adverse cardiac events (p=0.026), first cardiovascular hospitalization and repeat cardiac testing (p=0.0011) compared to those with normal GLS. Abnormal GLS appears to be a better predictor than abnormal WMSI in predicting major adverse cardiac events (p=0.174) and time to first cardiovascular hospitalization or repeat cardiac testing (p=0.0093).

Conclusion:

GLS may be a better predictor of long-term major adverse cardiac events, readmissions and repeat cardiac testing than WMSI in patients undergoing stress echocardiography.