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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Myocardial early systolic lengthening predicts mid-term outcomes in patients with hypertrophic cardiomyopathy

In this study, we investigated whether early systolic lengthening (ESL) which reflects subclinical ischemia and other echocardiographic and clinic parameters predict primary outcome [appropriate ICD shock, cardiovascular mortality and ventricular tachycardia (VT) or fibrillation] in patients with hypertrophic cardiomyopathy (HCM). 202 Patients with HCM (68% male, mean age 48 ± 13.9 years) were included in the study. Patients' clinical, electrocardiographic, 2D classic and speckle tracking echocardiography (STE) data were collected. ESL was defined as time from onset of the Q wave on ECG (onset of the R wave if the Q wave was absent) to maximum myocardial systolic lengthening. Patients were divided into two groups as occurrence or absence of primary outcome during 5 years follow up. During the follow-up period of 5 years (mean follow-up duration, 45.9 ± 10.8 months), 31 patients (15%) developed primary outcome [appropriate ICD shock 22 (11%), cardiovascular death 6 (3%), VT/VF 3(1.5%)]. Higher HCM Risk SCD score, longer ESL, and decreased global longitudinal peak strain (GLPS) were observed in patients with primary outcome. A Cox regression analysis, ESL, GLPS and HCM Risk SCD score were found to be independent predictors of occurrence of primary outcome. In ROC curve analysis, ESL > 53.5 msn could discriminate between groups with and without a primary outcome (AUC 0.768, 80% sensitivity and 60% specificity, CI 95% 0.666-0.871). ESL were found to be predictive for primary outcome in patients with HCM. Readily measurable ESL could be helpful to distinguish patients at high risk who could optimally benefit from ICD therapy.

Incremental value of early systolic lengthening and postsystolic shortening in detecting left anterior descending artery stenosis using nonstress speckle-tracking echocardiography

The diagnosis of coronary artery disease (CAD) with nonstress echocardiography remains challenging. Although the assessment of either early systolic lengthening (ESL) or postsystolic shortening (PSS) allows the sensitive detection of CAD, it is unclear whether the integrated analysis of ESL and PSS in addition to the peak systolic strain can improve the diagnostic accuracy. We investigated the incremental value of ESL and PSS in detecting left anterior descending artery (LAD) stenosis using nonstress speckle-tracking echocardiography. Fifty-nine patients with significant LAD stenosis but without visual wall motion abnormalities on echocardiography at rest (30 single-vessel stenosis, 29 multivessel stenosis) and 43 patients without significant stenosis of any vessel were enrolled. The peak systolic strain, the time to ESL (T_ESL), and the time to PSS (T_PSS) were analyzed in all LAD segments, and the incremental values of the T_ESL and T_PSS in detecting LAD stenosis and the diagnostic accuracy were evaluated. In the apical anterior segment, the peak systolic strain was significantly lower and T_ESL and T_PSS were significantly longer in the single-vessel group than in the no stenosis group. In the single-vessel group, the addition of T_ESL and T_PSS to the peak systolic strain significantly increased the model power in detecting stenosis, and the integrated analysis improved diagnostic accuracy compared with the peak systolic strain alone. In contrast, this incremental value was not demonstrated in the multivessel group. The integrated analysis of the peak systolic strain, ESL, and PSS may allow better screening of single-vessel LAD stenosis using nonstress speckle-tracking echocardiography.

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.

Duration of early systolic lengthening: prognostic potential in the general population

BACKGROUND

When the left ventricle pressure rises during early systole, myocardial fibres with reduced contractility tend to stretch instead of shortening. This interval is known as duration of early systolic lengthening (DESL). We sought to investigate if DESL provides prognostic information on cardiovascular events.

METHODS AND RESULTS

In this prospective study we included 1210 participants from a low-risk general population who underwent speckle tracking echocardiography (men 41%, mean age 56 years, SD 16). Primary endpoints were incident heart failure (HF), myocardial infarction (MI), and cardiovascular death (CVD). We defined DESL as time from onset of Q-wave on the electrocardiogram to peak positive systolic strain. In addition, we assessed the ratio between DESL and duration of cardiac systole, DESLsystole.During median follow-up of 16 years, 90 (7%) developed HF, 50 (4%) MI, and 70 (6%) experienced CVD. Both DESL [hazard ratio (HR) 1.58 95%CI 1.16-2.15, P = 0.004 per 10 ms increase] and DESLsystole (HR 1.74 95%CI 1.24-2.47, P = 0.001 per 1% increase) were predictors of HF. Similarly, DESL (HR 1.40 95%CI 1.09-1.78, P = 0.007 per 10 ms increase) and DESLsystole (HR 1.58 95%CI 1.01-2.49, P = 0.047 per 1% increase) were predictors of MI. No associations were found with CVD. After adjusting for clinical and echocardiographic parameters, the associations remained significant. DESLsystole was superior to systolic echocardiographic parameters for predicting HF (P = 0.012).

CONCLUSION

DESL and the novel index of DESLsystole provide independent and novel prognostic information on the risk of HF and MI in the general population. Evaluation of DESL should be explored in future echocardiographic studies.

Early systolic lengthening by speckle tracking echocardiography predicts outcome after coronary artery bypass surgery

BACKGROUND

Early systolic lengthening (ESL), a paradoxical stretch of myocardial fibers, has been linked to loss of myocardial viability and contractile dysfunction. We assessed the long-term prognostic potential of ESL in coronary artery bypass graft (CABG) patients.

METHODS

We retrospectively included patients (n = 709; mean age 68 years; 85% men) who underwent speckle tracking echocardiography (median 15 days) prior to CABG. Endpoints were cardiovascular death (CVD) and all-cause mortality. We assessed amplitude of ESL (%), defined as peak positive strain, and duration of ESL (ms), determined as time from Q-wave on the ECG to peak positive strain. We applied Cox models adjusted for clinical risk assessed as EuroSCORE II.

RESULTS

During median follow-up of 3.8 years [IQR 2.7-4.9 years], 45 (6%) experienced CVD and 80 (11%) died. In survival analyses adjusted for EuroSCORE II, each 1% increase in amplitude of ESL was associated with CVD (HR 1.35 [95%CI 1.09-1.68], P = 0.006) and all-cause mortality (HR 1.29 [95%CI 1.08-1.54], P = 0.004). Similar findings applied to duration of ESL (per 10ms increase) and CVD (HR 1.12 [95%CI 1.02-1.23], P = 0.016) and all-cause mortality (HR 1.09 [95%CI 1.01--1.17], P = 0.031). The prognostic value of ESL amplitude was modified by sex (P interaction < 0.05), such that the prognostic value was greater in women for both endpoints. When adding ESL duration to EuroSCORE II, the net reclassification index improved significantly for both CVD and all-cause mortality.

CONCLUSIONS

Assessment of ESL provides independent and incremental prognostic information in addition to the EuroSCORE II for CVD and all-cause mortality in CABG patients.

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.

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.

Prognostic Value of Early Systolic Lengthening by Strain Imaging in Type 2 Diabetes

BACKGROUND

Patients with type 2 diabetes (T2D) have increased risk for subclinical myocardial disease. Early systolic lengthening (ESL), a paradoxical stretch of myocardial fibers, is a sensitive marker of myocardial dysfunction. The aims of this study were to investigate the prognostic value of ESL in patients with T2D and to determine if global longitudinal strain (GLS) modifies this relationship.

METHODS

In this prospective study, speckle-tracking echocardiography was conducted in 703 patients with T2D (62% men; mean age, 63 ± 10 years; median diabetes duration, 11 years; interquartile range, 6-17 years). Patients had no histories of significant heart disease. ESL index was assessed as [-100 × (peak positive systolic strain/maximal strain)] and ESL duration as time from QRS complex on the electrocardiogram to time of peak positive systolic strain. P values ≤ .004 were considered to indicate statistical significance.

RESULTS

During a median follow-up time of 4.8 years (interquartile range, 4.1-5.3 years), 86 patients (12%) experienced major adverse cardiovascular events (MACE), a composite of incident heart failure, myocardial infarction, and cardiovascular death. In multivariate models, only the ESL index (hazard ratio [HR], 1.06 per 1% increase; 95% CI, 1.01-1.010; P = .004) but not ESL duration (HR, 1.02 per 1-ms increase; 95% CI, 1.00-1.03; P = .036) were associated with MACE. GLS modified this relationship (P for interaction < .05) such that in patients with low GLS (>-18%), ESL index (HR, 1.06 per 1% increase; 95% CI, 1.02-1.10; P = .003) was associated with MACE, but ESL duration was not (HR, 1.02 per 1-ms increase; 95% CI, 1.00-1.04; P = .005). No associations were found for high GLS (<-18%).

CONCLUSIONS

In patients with T2D and no histories of heart disease, ESL provides prognostic information on MACE and may potentially aid in cardiovascular risk stratification.

Early Systolic Lengthening in Patients With ST-Segment-Elevation Myocardial Infarction: A Novel Predictor of Cardiovascular Events

Background Early systolic lengthening (ESL) may occur in ischemic myocardial segments with reduced contractile force. We sought to evaluate the prognostic potential of ESL in patients with ST-segment-elevation myocardial infarction treated with primary percutaneous coronary intervention. Methods and Results We prospectively enrolled 373 patients with ST-segment-elevation myocardial infarction treated with primary percutaneous coronary intervention. All patients underwent a speckle tracking echocardiographic examination a median of 2 days (interquartile range, 1-3 days) after the percutaneous coronary intervention. We assessed a novel viability index, the ESL index, defined as follows: [-100×(peak positive systolic strain/peak negative strain in cardiac cycle)]. We also calculated ESL duration, defined as time from onset of QRS complex on the ECG to time of peak positive systolic strain. Both parameters were averaged from 18 myocardial segments. During a median follow-up of 5.3 years (interquartile range, 2.5-6.0 years), 145 (39%) experienced major adverse cardiovascular events, a composite of incident heart failure, new myocardial infarction, and all-cause mortality. The ESL index and ESL duration were significantly increased in culprit lesion areas (6.7±6.2% versus 5.0±4.1% and 43±33 ms versus 33±24 ms, respectively; P<0.001 for both). In Cox proportional hazard models, the ESL index (hazard ratio, 1.27 per 1% increase; 95% CI, 1.13-1.43; P<0.001) and ESL duration (hazard ratio, 1.49 per 1-ms increase; 95% CI, 1.15-1.92; P=0.002) yielded prognostic information on major adverse cardiovascular events. Both associations remained significant after adjusting for clinical, echocardiographic, and invasive confounders. Conclusions Assessment of ESL after primary percutaneous coronary intervention in patients with ST-segment-elevation myocardial infarction yields independent and significant prognostic information on the future risk of cardiovascular events.

Assessment of Myocardial Ischemic Memory Using Three-Dimensional Speckle-Tracking Echocardiography: A Novel Integrated Analysis of Early Systolic Lengthening and Postsystolic Shortening

BACKGROUND

Persistence of subtle abnormal myocardial deformation such as postsystolic shortening (PSS) after transient ischemia can be used to diagnose a history of myocardial ischemia (myocardial ischemic memory). Furthermore, early systolic lengthening (ESL) has recently attracted attention as another marker of myocardial ischemia. However, it is unclear whether the persistence of such abnormal deformation can be detected by three-dimensional (3D) speckle-tracking echocardiography, which has relatively low spatial and temporal resolution compared with two-dimensional echocardiography. The aim of this study was to evaluate the diagnostic accuracy of myocardial ischemic memory and its spatial extent using 3D speckle-tracking echocardiography.

METHODS

The left circumflex coronary artery was occluded for 2 min, followed by reperfusion, in 33 dogs. Their hemodynamic and 3D echocardiographic data were chronologically acquired. Peak systolic strain, early systolic strain index as a parameter of ESL, postsystolic strain index as a parameter of PSS, and myocardial dysfunction index as a combined parameter of ESL and PSS were analyzed in all left ventricular segments.

RESULTS

At the center of the risk area, early systolic strain index and postsystolic strain index significantly increased until 20 min after reperfusion compared with baseline, although peak systolic strain recovered by 20 min. Myocardial dysfunction index significantly increased for >20 min after reperfusion and allowed better diagnostic accuracy of ischemic memory than the other parameters. In the 147 risk segments, abnormal values of myocardial dysfunction index remained in 49 segments (33%) at 20 min after reperfusion, whereas abnormal peak systolic strain was observed in only 13 segments (9%).

CONCLUSIONS

ESL and PSS persisted after transient ischemia and could be detected by 3D speckle-tracking echocardiography. Integrated analysis of ESL and PSS provided higher diagnostic accuracy of ischemic memory. This method may be useful for detecting transient ischemic insults in patients after the disappearance of anginal attack.

The duration of early systolic lengthening may predict ischemia from scar tissue in patients with chronic coronary total occlusion lesions

In this study, we aimed to investigate the predictive value of early systolic lengthening duration in differentiating myocardial ischemia from scar tissue in patients with chronic coronary total occlusion. A total of 69 patients were included in the study. The participating patients were divided into two groups as 35 patients with ischemia and 34 patients with scar tissue based on the results of the myocardial perfusion scintigraphy. In the scar group compared to the ischemia group; LVEF, GLS, SRS', and the duration of early systolic lengthening were significantly lower; whereas, EDV, ESV, and WMSI were significantly higher in the scar group compared to the ischemia group. In the multivariate logistic regression test, LVEF (OR 1.150, 95% CI 1.044-1.268, p = 0.005) and duration of early systolic lengthening (OR 1.021, 95% CI 1.004-1.039, p = 0.016) were determined as independent predictive parameters for ischemia detected by myocardial perfusion scintigraphy. Duration of early systolic lengthening obtained by speckle tracking echocardiography in patients with chronic total occlusion lesions may be useful in differentiating ischemia from scar tissue detected in myocardial perfusion scintigraphy. Prolonged duration of early systolic lengthening in patients with chronic total occlusion lesions was related to the presence of ischemia detected by myocardial perfusion scintigraphy.

Speckle Tracking Echocardiography in Non-ST-Segment Elevation Acute Coronary Syndromes

Non-ST-segment elevation acute coronary syndromes (NSTE-ACSs) are a group of clinical conditions characterized by acute myocardial ischemia. Conventional echocardiography is generally used to evaluate cardiac function using wall motion analysis and left ventricular ejection fraction but may be insufficient to explore all the complex features of NSTE-ACSs, which may vary substantially from patient to patient in terms of severity of ischemia and extent of involved myocardium. In the last years, speckle tracking echocardiography (STE) has become a widely available technique for the non-invasive assessment of cardiac function and has been repeatedly applied in the setting of NSTE-ACSs. In this review we summarize current evidence about the use of STE in patients with NSTE-ACSs, trying to underline advantages and limitations in comparison with conventional echocardiography for: diagnosis of NSTE-ACS, differential diagnosis, identification of high-risk patients, and prediction of outcome.

Duration of myocardial early systolic lengthening for diagnosis of coronary artery disease

Objective

Myocardial early systolic lengthening (ESL) duration is prolonged in patients with coronary artery disease (CAD). However, the relationship between the fractional flow reserve (FFR), the current gold standard for evaluating physiological myocardial ischaemia, and ESL has not been studied. The aims of this study were to investigate whether left ventricular (LV) ESL duration could identify patients with CAD, and to examine the relationship between FFR and LV ESL duration.

Methods

In this single-centre, cross-sectional, prospective study of 75 patients with suspected or known CAD, we performed two-dimensional speckle tracking echocardiography at rest on the day before coronary angiography or percutaneous coronary intervention. Apical 3 views were used to examine ESL duration, defined as time from onset of the Q wave to maximum myocardial systolic lengthening.

Results

Thirty-five patients had non-significant stenosis. Forty patients with CAD underwent FFR testing: 17 had an FFR≥0.8 and 23 had an FFR<0.8. Global ESL duration was 20.9±22.2 ms in patients with non-significant stenosis, 36.4±23.2 ms in patients with FFR≥0.8 and 39.6±29.5 ms in patients with FFR<0.8 (p=0.020). However, global and regional ESL durations were not significantly correlated with FFR and demonstrated poor reproducibility.

Conclusion

Although myocardial ESL duration was significantly prolonged in patients with CAD compared with patients without CAD, ESL at rest showed poor reproducibility, and this new parameter did not predict FFR in patients with suspected CAD.

Noninvasive cardiac imaging in suspected acute coronary syndrome

Noninvasive cardiac imaging has an important role in the assessment of patients with acute-onset chest pain. In patients with suspected acute coronary syndrome (ACS), cardiac imaging offers incremental value over routine clinical assessment, the electrocardiogram, and blood biomarkers of myocardial injury, to confirm or refute the diagnosis of coronary artery disease and to assess future cardiovascular risk. This Review covers the current guidelines and clinical use of the common noninvasive imaging techniques, including echocardiography and stress echocardiography, computed tomography coronary angiography, myocardial perfusion scintigraphy, positron emission tomography, and cardiovascular magnetic resonance imaging, in patients with suspected ACS, and provides an update on the developments in noninvasive imaging techniques in the past 5 years.

Strain Echocardiography and Myocardial Mechanics: From Basics to Clinical Applications

The aim of this review is to summarize the recent developments in strain imaging, an evolving technique – from tissue Doppler to 3D echocardiography – for resolving the complex left ventricular mechanics. Following a brief overview of the different used technique to extract myocardial deformation data, the authors summarize the role of the technique in the assessment of cardiac mechanics and its role in the clinical arena.