Bedside Assessment of Myocardial Viability Using Transmural Strain Profile in Patients With ST Elevation Myocardial Infarction: Comparison With Cardiac Magnetic Resonance Imaging

Magnetic Resonance Imaging of Myocardial Strain After Acute ST-Segment-Elevation Myocardial Infarction: A Systematic Review

The purpose of this systematic review is to provide a clinically relevant, disease-based perspective on myocardial strain imaging in patients with acute myocardial infarction or stable ischemic heart disease. Cardiac magnetic resonance imaging uniquely integrates myocardial function with pathology. Therefore, this review focuses on strain imaging with cardiac magnetic resonance. We have specifically considered the relationships between left ventricular (LV) strain, infarct pathologies, and their associations with prognosis. A comprehensive literature review was conducted in accordance with the PRISMA guidelines. Publications were identified that (1) described the relationship between strain and infarct pathologies, (2) assessed the relationship between strain and subsequent LV outcomes, and (3) assessed the relationship between strain and health outcomes. In patients with acute myocardial infarction, circumferential strain predicts the recovery of LV systolic function in the longer term. The prognostic value of longitudinal strain is less certain. Strain differentiates between infarcted versus noninfarcted myocardium, even in patients with stable ischemic heart disease with preserved LV ejection fraction. Strain recovery is impaired in infarcted segments with intramyocardial hemorrhage or microvascular obstruction. There are practical limitations to measuring strain with cardiac magnetic resonance in the acute setting, and knowledge gaps, including the lack of data showing incremental value in clinical practice. Critically, studies of cardiac magnetic resonance strain imaging in patients with ischemic heart disease have been limited by sample size and design. Strain imaging has potential as a tool to assess for early or subclinical changes in LV function, and strain is now being included as a surrogate measure of outcome in therapeutic trials.

2D speckle tracking echocardiography for the assessment of regional contractile reserve after myocardial infarction

AIMS

To assess whether quantitative resting assessment of local myocardial function by 2D speckle tracking echocardiography may be helpful for the evaluation of myocardial viability in patients after ST-elevation myocardial infarction (STEMI) and for the prediction of left ventricular function recovery after 12-month follow-up.

METHODS

The study group comprised 96 patients with first STEMI treated with successful primary percutaneous coronary intervention. Seven to 12 days after STEMI, all patients underwent resting echocardiography and low-dose dobutamine stress echocardiography (LDDSE) with visual assessment of contractile reserve which was the reference method for the evaluation of myocardial viability. After 12 months resting echocardiography with visual assessment of functional recovery was performed. Subsequently, acquired images were analyzed off-line using 2D speckle tracking echocardiography algorithm. Measurements included peak systolic longitudinal and transverse strain (SLS/STS), peak longitudinal and transverse strain (PLS/PTS), systolic longitudinal and transverse strain rate (SLSR/STSR) at baseline and after 12 months.

RESULTS

All analyzed longitudinal parameters of strain had a very good diagnostic value, while transverse parameters had only good diagnostic value for predicting myocardial viability defined on the basis of LDDSE. Moreover, SLS and PLS had good, whereas SLSR only satisfactory diagnostic value for predicting function recovery after 12-month follow-up.

CONCLUSIONS

2D speckle tracking analysis applied during resting echocardiography can be helpful for the prediction of myocardial viability and functional recovery in patients after STEMI. Longitudinal strain parameters allow the prediction of local contractile reserve with SLS showing best correlation with DSE results functional recovery after 12-month follow-up.

Strain Imaging: From Physiology to Practical Applications in Daily Practice

Non-Doppler, 2-dimensional strain imaging is a new echocardiographic technique for obtaining strain and strain rate measurements, which serves as a major advancement in understanding myocardial deformation. It analyzes motion in ultrasound imaging by tracking speckles in 2 dimensions. There are a lot of data emerging with multiple applications of strain imaging in the clinical practice of echocardiography. As incorporation of strain imaging in daily practice has been challenging, we intend to systematically highlight the top 10 applications of speckle-tracking echocardiography, which every cardiologist should be aware of: chemotherapy cardiotoxicity, left ventricular assessment, cardiac amyloidosis, hypertrophic obstructive cardiomyopathy, right ventricular dysfunction, valvular heart diseases (aortic stenosis and mitral regurgitation), cardiac sarcoidosis, athlete heart, left atrial assessment, and cardiac dyssynchrony.

Quantitative analysis of endocardial and epicardial left ventricular myocardial deformation-comparison of strain-encoded cardiac magnetic resonance imaging with two-dimensional speckle-tracking echocardiography

BACKGROUND

Quantitative analysis of segmental myocardial deformation of different myocardial layers has become possible using strain-encoded cardiac magnetic resonance imaging (SENC) and speckle-tracking echocardiography (STE). We evaluated and compared the quantitative analysis of myocardial deformation using SENC and STE.

METHODS

In 44 patients (age 61 ± 13 years, 34 men), SENC by cardiac magnetic resonance imaging using a 1.5-Tesla whole-body scanner and two-dimensional STE were performed prospectively. Quantitative layer-specific analysis of segmental left ventricular function was performed to determine the peak circumferential and peak longitudinal systolic strain values using SENC and STE of an endocardial and epicardial myocardial layer. In addition, segmental function was defined as normokinetic, hypokinetic, or akinetic by visual analysis of the magnetic resonance imaging cine sequences.

RESULTS

The endocardial and epicardial strain defined by SENC or STE differed significantly between the visually defined segmental function states. The correlation of the peak circumferential endocardial strain by SENC versus STE (intraclass correlation coefficient [ICC] 0.493, 95% CI 0.358-0.597) tended to be better than the correlation of the circumferential epicardial strain using both methods (ICC 0.321, 95% CI 0.238-0.399). The correlation of the peak longitudinal endocardial strain by SENC and STE was similar (ICC 0.472, 95% CI 0.398-0.541), in contrast to the longitudinal epicardial strain analysis by both techniques (ICC 0.554, 95% CI 0.417-0.655). Circumferential strain analysis by STE allowed better distinction of the hypokinetic or akinetic segments from the normokinetic segments than did the circumferential strain analysis by SENC of the endocardial layer (area under the receiver operating characteristic curve [AUC ROC] 0.946 vs 0.884; P < .001) or epicardial layer (AUC ROC 0.884 vs 0.782; P < .001). Longitudinal strain analysis using STE and SENC of the endocardial layer (AUC ROC 0.851 vs 0.839; P = .5838) and epicardial layer (AUC ROC 0.849 vs 0.833; P = .4321) had similar diagnostic value for identifying the presence of hypokinetic and akinetic segments.

CONCLUSIONS

Quantitative analysis of segmental deformation by SENC and STE allowed accurate distinction of myocardial segments with different functional states. Circumferential endocardial strain analysis by STE allowed the best distinction of segments with impaired function from the normokinetic segments.

Cardiac ultrasound imaging in heart failure: recent advances

Several new imaging modalities are being utilized in the management of heart failure. Echocardiography and speckle tracking imaging offer clinician the benefits of easy accessibility, real time data interpretation and objective quantification of heart function. Accordingly, this article reviews the current evidence base related to the use of echocardiography and other advanced ultrasonography techniques in heart failure, and discusses applications as well as limitations of these emerging technologies. The role of cardiac resynchronization therapy (CRT) and implications of the PROSPECT (Predictors of Response to CRT) trial in management of heart failure are also reviewed. The article concludes with a discussion about the evolving role of echocardiography in diagnosis and management of subclinical heart disease, so that preventive strategies may be devised.

Dobutamine Stress Echocardiography for the Bedside Assessment of Viability Following a Motor Vehicle Accident and Subsequent Myocardial Infarction: A Case Report

The authors describe a case of a critically ill patient presenting after motor vehicle trauma complicated by anterior myocardial infarction and cardiogenic shock. Assessment of myocardial viability in the territory of a critically stenosed left anterior descending artery (LAD) was necessary to determine the optimal management strategy. Bedside dobutamine stress echocardiography (DSE) demonstrated viability in the LAD territory and the patient underwent uncomplicated single-vessel bypass surgery with subsequent improvement in left-ventricular function. This case illustrates the utility of bedside DSE to assess myocardial viability in patients for whom other non-invasive modalities are not feasible.

Global left ventricular longitudinal systolic strain for early risk assessment in patients with acute myocardial infarction treated with primary percutaneous intervention

BACKGROUND

Left ventricular systolic function is a key determinant of outcome after ST-segment elevation myocardial infarction (STEMI). The aim of this study was to study speckle-tracking global longitudinal strain (GLS) for early risk evaluation in STEMI and compare it with left ventricular ejection fraction (LVEF), wall motion score index (WMSI), and end-systolic volume index (ESVI).

METHODS

Five-hundred seventy-six patients underwent echocardiography ≤24 hours after primary percutaneous coronary intervention for STEMI. The end point was the composite of death, hospitalization with reinfarction, congestive heart failure, or stroke. Associations with outcome were assessed by multivariate Cox regression with adjustment for clinical parameters. Hazard ratios (HRs) for events within the first year are reported per absolute percentage GLS increase.

RESULTS

During a median follow-up period of 24 months, 162 patients experienced at least one event. GLS was associated with the composite end point (adjusted HR, 1.20; 95% confidence interval [CI], 1.12-1.29) and also when controlling for LVEF (adjusted HR, 1.17; 95% CI, 1.07-1.29) and ESVI (adjusted HR, 1.18; 95% CI, 1.08-1.28). Although WMSI was significantly associated with outcome beyond any association accounted for by GLS, a borderline significant association was found after controlling for WMSI (adjusted HR for GLS, 1.10; 95% CI, 1.00-1.21). When GLS or WMSI was known, there was no significant association between LVEF or ESVI and outcome.

CONCLUSIONS

In a large population of patients with STEMI, GLS and WMSI were comparable and both superior for early risk assessment compared with volume-based left ventricular function indicators such as LVEF and ESVI. Compared with WMSI, the advantage of GLS is the provision of a semiautomated quantitative measure.

Prognostic value of serial global longitudinal strain measured by two-dimensional speckle tracking echocardiography in patients with ST-segment elevation myocardial infarction

The aim of this study was to determine whether assessment of global longitudinal strain (GLS) before revascularization could predict adverse cardiac events after ST-segment elevation myocardial infarction (STEMI). In addition, the relation between GLS and cardiac biomarkers was investigated. From July 2006 through December 2009, 98 patients with first STEMI underwent conventional and speckle tracking echocardiography at initial presentation and 3 days after primary coronary intervention. Patients were divided into 3 groups according to percent changes of GLS compared to baseline GLS values: group 1, improved GLS >10%; group 2, unchanged GLS from -10% to 10%; and group 3, decreased GLS <-10%. Subsequent complications including all-cause mortality and readmission because of congestive heart failure during a 6-month period of follow-up were prospectively evaluated. After coronary intervention, GLS was improved in 29 patients (30%, group 1), unchanged in 55 patients (56%, group 2), and worsened in 14 patients (14%, group 3). Complications developed in 7 patients (group 1, n = 0, 0%; group 2, n = 2, 28%; group 3, n = 5, 72%, p <0.01). Multivariate Cox analysis showed an independent association of GLS before and after coronary intervention with subsequent complications. Significant correlations were observed between GLS and cardiac biomarkers. In conclusion, GLS assessment before coronary intervention was a good predictor of complications in patients with STEMI comparable to predictions using GLS after intervention at 6-month follow-up.