Identification of Viable Myocardium in Acute Anterior Infarction Using Duration of Systolic Lengthening by Tissue Doppler Strain: A Preliminary Study

The association between myocardial early systolic lengthening and high risk angiographic territory involvement in patients with non-ST-segment elevation myocardial infarction

BACKGROUND

Non-ST-segment elevation myocardial infarction (NSTEMI) is more common than ST-segment elevation myocardial infarction (STEMI), consisting of 60-70% of myocardial infarctions. When left ventricular (LV) pressure increases during early systole, regionally ischaemic myocardium with a reduced active force exhibit stretching. The aim of this study was to evaluate the role of this parameter in determining high risk angiographic territory involvement in NSTEMI patients.

RESULTS

This study was a descriptive correlational research that was conducted on 96 patients with NSTEMI and a left ventricular ejection fraction ≥ 50% who underwent coronary angiography (CAG). Patients were divided into two groups based on having or not having high risk angiographic territory involvement in CAG. All patients underwent a transthoracic echocardiography during the first day of hospitalization and early systolic lengthening (ESL), duration of ESL (DESL), left ventricular global longitudinal strain (LVGLS), pulsed-wave Doppler-derived transmitral early (E wave) and late (A wave) diastolic velocities, and tissue-Doppler-derived mitral annular early diastolic (e') and peak systolic (s') velocities were determined. The results of this study showed DESL, DESLLAD, and DESLLCX were longer in high risk angiographic territory group than other one (P value 0.016, 0.044, and 0.04, respectively). The logistic regression analysis showed among different variables, only age and ESLLAD had an independent association with high risk angiographic territory involvement (P = 0.01, odds ratio [OR] 1.09, 95% CI 1.021-1.164, and P = 0.024, odds ratio [OR] 1.243, 95% CI 1.029-1.50, respectively).

CONCLUSIONS

Assessment of myocardial ESLLAD by speckle-tracking echocardiography may be helpful in predicting high risk angiographic territory involvement in patients with NSTEMI. Indeed, a higher value can be considered as a high risk parameter which may show benefit of an early invasive strategy versus a conservative approach.

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 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.

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.

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.

Prediction of left ventricular contractile recovery using tissue Doppler strain and strain rate measurements at rest in patients undergoing percutaneous coronary intervention

The aim of the study was to assess the ability of tissue Doppler (TD) deformation analysis at rest to predict left ventricular contractile recovery in patients undergoing percutaneous coronary intervention (PCI). This prospective cohort enrolled 67 patients with segmental wall motion abnormality. Assessment of each segment was performed at rest and during low dose Dobutamine stress echocardiography (DSE) using a 4 point scoring system, TD peak systolic strain (PSS) and peak systolic strain rate (PSSR). The study followed up the patients for contractile improvement after 6 months of successful PCI by echocardiography. Of a 319 dysfunctional segments, 155 (49%) showed contractile recovery and 164 (51%) did not. PSS and PSSR at rest were significantly higher in recovered segments compared to segments without recovery (PSS: -7.27 ± 0.8 Vs. -6.14 ± 0.7%, PSSR: -0.34 ± 0.13 Vs. -0.24 ± 0.1/s. p < 0.0001 both). Similarly, both parameters were significantly higher in the contractile recovery group at follow up (p 0.001). Resting PSSR as well as PSS and PSSR during DSE were significant independent predictors of contractile recovery (p < 0.001 each). For predicting segmental contractile recovery, resting PSSR with a -0.31/s cut-off point had 76% sensitivity and 59% specificity (AUC 0.74), DSE qualitative viability assessment had a sensitivity of 75% and specificity of 77%, DSE PSS with a cut-off point of -9.1% had 74% sensitivity and 63% specificity (AUC 0.77) and DSE PSSR with a cut-off point of -0.72/s had 78% sensitivity and 77% specificity (AUC 0.81). Resting PSSR is a modest predictor of segmental contractile recovery after PCI while PSSR during DSE has a comparable diagnostic performance to subjective wall motion scoring. Recovered segments show improvement of deformation parameters after PCI.

Strain Analysis in the Detection of Myocardial Infarction at the Acute and Chronic Stages

BACKGROUND

Myocardial ischemia causes contractile dysfunction in ischemic, stunned, and tethered regions with larger infarcted zones having a negative prognostic impact on patients' outcomes. To distinguish the infarcted myocardium from the other regions, we investigated the diagnostic potential of circumferential strain (CS) and radial strain (RS) during the acute and chronic stages of myocardial infarction.

METHODS

Ten pigs underwent 90-minute occlusion of the left anterior descending artery, followed by reperfusion. Echocardiography was performed at baseline, after 90-minute occlusion, and at 2 hours, 30, and 60 days postreperfusion. CS and RS were measured using speckle tracking echocardiography. Subsequently, the pigs were sacrificed, and histological analysis for infarct size was performed.

RESULTS

After 90-minute occlusion, reduced strains were detected for all segments (infarcted anterior wall - baseline: CS: -17.6 ± 5.7%, RS: 54.4 ± 16.9%; 90 min: CS: -10.3 ± 3.0%, RS: 23.3 ± 7.0%; tethered posterior wall - baseline: CS: -18.4 ± 3.5%, RS: 68.7 ± 21.1%; 90 min: CS: -10.7 ± 6.4%, RS: 34.5 ± 14.7%, P < 0.001). However, postsystolic shortening was detected only in the infarcted segments, and the time-to-peak CS was 25% longer (P < 0.05). At 30 and 60 days postreperfusion, time-to-peak CS could only detect large scars in the anterior and anterior-septum walls (P < 0.05), while peak CS also detected smaller scars in the lateral wall (P < 0.05). RS failed to distinguish between normal, stunned/tethered, and infarcted myocardium.

CONCLUSIONS

During occlusion and 2 hours postreperfusion, time-to-peak CS could distinguish between infarcted and stunned/tethered myocardial segments, while at 30 and 60 days postreperfusion, peak CS was the best detector of infarction.

Relationship between acute strain pattern and recovery in tako-tsubo cardiomyopathy and acute anterior myocardial infarction: a comparative study using two-dimensional longitudinal strain

After acute-anterior myocardial infarction (AMI), left ventricular (LV) viable myocardial segments show some degree of active deformation (longitudinal shortening) despite wall motion abnormalities (WMA). Tako-tsubo cardiomyopathy (TTC) is characterized by myocardial stunning; however, it is unclear whether in TTC the strain pattern mimics AMI. To compare the strain-pattern in TTC and AMI using the 2D-longitudinal strain by speckle-tracking in segments with WMA, and its relationship with recovery of function at follow-up. 21 consecutive patients with typical TTC and 21 age-matched AMI patients treated by primary angioplasty had an analysis of LV-longitudinal strain at the acute-phase and at follow-up (1 and 6 months later for TTC and AMI respectively). The recovery of a segment was defined as normal wall motion at follow-up. Among the 706 analyzable LV-segments at the acute-phase, 406 had WMA (TTC 229, AMI 177). At follow-up, total recovery was observed for 45 % segments in AMI and 100 % in TTC, (p < 0.01). At the acute phase, systolic lengthening duration (47 ± 43 vs. 18 ± 33 %) and amplitude (0.25 ± 0.29 vs. 0.09 ± 0.19) and post systolic shortening (67 ± 53 vs. 39 ± 38 %) were higher in TTC, when compared to AMI-recovery (all, p < 0.01). In AMI, systolic lengthening duration was an independent predictor of poor recovery in multivariate analysis, linked to segmental longitudinal strain at follow-up (all, p ≤ 0.01). Furthermore, among the 57 % of segments exhibiting any systolic lengthening duration in AMI, only ¼ recovered, versus 62 % of such segments in TTC with 100 % recovery (p < 0.001). The systolic passive motion which is closely and inversely linked to recovery in AMI is paradoxically frequent and severe in TTC. This suggests that myocardial stunning in TTC and AMI is different according to longitudinal strain.

The most important publications of the past year in echocardiography

We review the published literature on clinical echocardiography of the past year. Key topics were valvular heart disease, in particular aortic stenosis, and the imaging requirements for transcatheter aortic valve implantation. Three-dimensional echocardiography and deformation imaging have yielded important new insights in valvular heart disease. Other key fields have been assessment of heart failure, in particular heart failure with preserved ejection fraction, and the relationship of this condition with diastolic dysfunction and left atrial function. Functional imaging of cardiomyopathies was also an important topic.