Improved recognition of dysfunctioning myocardial segments by longitudinal strain rate versus velocity in patients with myocardial infarction

Deep learning automates detection of wall motion abnormalities via measurement of longitudinal strain from ECG-gated CT images

Introduction

4D cardiac CT (cineCT) is increasingly used to evaluate cardiac dynamics. While echocardiography and CMR have demonstrated the utility of longitudinal strain (LS) measures, measuring LS from cineCT currently requires reformatting the 4D dataset into long-axis imaging planes and delineating the endocardial boundary across time. In this work, we demonstrate the ability of a recently published deep learning framework to automatically and accurately measure LS for detection of wall motion abnormalities (WMA).

Methods

One hundred clinical cineCT studies were evaluated by three experienced cardiac CT readers to identify whether each AHA segment had a WMA. Fifty cases were used for method development and an independent group of 50 were used for testing. A previously developed convolutional neural network was used to automatically segment the LV bloodpool and to define the 2, 3, and 4 CH long-axis imaging planes. LS was measured as the perimeter of the bloodpool for each long-axis plane. Two smoothing approaches were developed to avoid artifacts due to papillary muscle insertion and texture of the endocardial surface. The impact of the smoothing was evaluated by comparison of LS estimates to LV ejection fraction and the fractional area change of the corresponding view.

Results

The automated, DL approach successfully analyzed 48/50 patients in the training cohort and 47/50 in the testing cohort. The optimal LS cutoff for identification of WMA was -21.8, -15.4, and -16.6% for the 2-, 3-, and 4-CH views in the training cohort. This led to correct labeling of 85, 85, and 83% of 2-, 3-, and 4-CH views, respectively, in the testing cohort. Per-study accuracy was 83% (84% sensitivity and 82% specificity). Smoothing significantly improved agreement between LS and fractional area change (R 2: 2 CH = 0.38 vs. 0.89 vs. 0.92).

Conclusion

Automated LV blood pool segmentation and long-axis plane delineation via deep learning enables automatic LS assessment. LS values accurately identify regional wall motion abnormalities and may be used to complement standard visual assessments.

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.

Physiological left ventricular segmental myocardial mechanics: Multiparametric polar mapping to determine intraventricular gradients of myocardial dynamics

OBJECTIVE

We investigated physiological systolic left ventricular (LV) myocardial mechanics and gradients to provide a database for later studies of diseased hearts.

METHODS

The analyses were performed in 131 heart-healthy individuals and included seven parameters of myocardial mechanics using speckle tracking echocardiography (STE).

RESULTS

Basal to apical and circumferentially significant physiological intraventricular parameter gradients of myocardial activity were determined. Global mean values and segmental ranges were peak systolic longitudinal strain -21.2 ± 3.3%, 95% confidence interval [CI] -21.8% to -20.6%), gradient (basal to apical) -16.0% to -26.7%; peak systolic longitudinal strain rate -1.24 ± 0.31%/s, 95% CI -1.29% to -1.19%/s, gradient (basal to apical) -0.91% to -1.61%/s; post-systolic index 2.6 ± 3.2%, 95% CI 3.15%-2.05%, gradient (basal/medial/apical) 7.0/1.2/2.4%; pre-systolic stretch index 1.3 ± 2.7%, 95% CI 1.77%-0.83%, gradient (basal/medial/apical) 6.5/0.2/1.3%; peak longitudinal displacement 12.2 ± 2.6 mm, 95% CI 12.6-11.8 mm, gradient (basal to apical) 21.0-3.4 mm; time-to-peak longitudinal strain 370 ± 43 ms, 95% CI 377-363 ms, gradient (basal to apical) 396-361 ms; and time-to-peak longitudinal strain rate 180 ± 47 ms, 95% CI 188-172 ms, gradient (basal to apical) 150-200 ms.

CONCLUSION

This study generated a database of seven STE-derived parameters of physiological segmental and global myocardial LV mechanics. The resulting sets of three-dimensional intraventricular mappings of the entire LV provide physiological parameter gradients in baso-apical and circumferential direction by applying the 17-segment polar model. This will facilitate comparison of systolic myocardial activity of the healthy LV with diseased or otherwise altered (eg, sports) hearts.

Speckle tracking analysis in intensive care unit: A toy or a tool?

The use of conventional echocardiography in the intensive care unit (ICU) is today established to assess left and right ventricular systolic function, for preload determination and procedural guidance. Next step in ICU echocardiography could be the use of novel ultrasound techniques such as strain echocardiography to assist in the management of patients with acute coronary syndrome, heart failure, or pulmonary embolism. This review has gathered the available evidence supporting the incremental value of strain in the diagnostic workup of cardiac diseases treated in ICU.

Early Speckle-tracking Echocardiography Predicts Left Ventricle Remodeling after Acute ST-segment Elevation Myocardial Infarction

Background:

Prediction of the left ventricular remodeling (LVR) after ST-segment elevation myocardial infarction (STEMI) in patients treated with effective myocardial reperfusion is challenging.

Methods:

Forty-one consecutive patients (36 males, age 59 ± 10 years) with STEMI who underwent effective (TIMI III) primary coronary angioplasty were enrolled. All patients had an echocardiography and cardiac magnetic resonance (CMR) study within 72 h from revascularization. Three echocardiographic parameters including LV ejection fraction (EF), global longitudinal strain (GLS) and severe altered longitudinal strain (SAS) area by two-dimensional speckle-tracking echocardiography (2D-STE) and 3 CMR indices including LV global function index (LV-GFI), myocardial salvage index (MSI), and microvascular obstruction (MVO) were calculated. LVR was defined as an increase in CMR LV end-diastolic volume (EDV) >15% after 6 months.

Results:

Of 41 patients, 10 (24%) had LVR (LV-EDV from 145.1 ± 29.3 to 185.9 ± 49.8 ml, P < 0.001). A significant correlation with LV-EDV variation was found for baseline SAS area (r = 0.81), LV-GFI (r = −0.56), MVO (r = 0.55), EF (r = −0.42), GLS (r = 0.42), not for MSI (r = −0.25). At the multivariable analysis, a significant correlation remained only for the SAS area. The receiver-operating characteristic curve analysis showed that a baseline SAS area ≥15% predicts LVR with a sensitivity of 80.0% and a specificity of 90.3%.

Conclusions:

The SAS area evaluated by 2D-STE early in acute STEMI is a valuable predictor of LVR after 6 months. Further investigations are needed to verify its value in predicting patient survival.

Risk stratification of patients with non-ST-elevation acute coronary syndromes by assessing global longitudinal strain

Noninvasive detection of left main/three-vessel diseases (LM/3VD) among patients with non-ST-elevation acute coronary syndromes (NSTEACS) has been difficult using echocardiography. However, two-dimensional (2D) strain/strain-rate analysis is more sensitive in quantitatively assessing contractile abnormality. Accordingly, we aimed to clarify the usefulness of 2D strain/strain-rate analysis for risk stratification of NSTEACS. A total of 50 patients with NSTEACS underwent echocardiography and coronary angiography. We evaluated global longitudinal peak strain (global PS), peak systolic strain rate (global SSR), early diastolic global peak strain rate (global ESR), time from aortic valve closure to peak strain (TAVC-global PS), and global ESR (TAVC-global ESR) in apical four-, two-, and three-chamber views. Patients were divided into two groups according to coronary angiographic findings, the high-risk group (n = 15) with either of left main or three-vessel disease, and the low-risk group (n = 35). There were no significant differences in global SSR and global ESR between the two groups. The amplitude of global PS was significantly reduced in high-risk patients with LM/3VD in comparison with low-risk patients (-17.5 ± 2.4% vs -19.8 ± 2.7%, P = 0.007, respectively). TAVC-global PS and TAVC-global ESR were significantly prolonged in high-risk patients with LM/3VD in comparison with low-risk patients (15.3 ± 25.7 ms vs -36.8 ± 32.7 ms, P < 0.0001 and 162.8 ± 32.7 ms vs 135.7 ± 41.5 ms, P < 0.03, respectively). Receiver-operating characteristic analysis demonstrated that TAVC-global PS most strongly detected high-risk patients with sensitivity of 100% and specificity of 74.3% (area under the curve = 0.938, 95 % confidence interval 0.832-0.986, P = 0.0001). Temporal analysis of 2D strain appeared to be useful in detecting high-risk patients with LM/3VD among patients with NSTEACS.

Acute Cardiac Resynchronization Therapy for the Failing Left, Right, or Single Ventricle After Repaired Congenital Heart Disease

Use of cardiac resynchronization in children and young adults with congenital heart disease has been described in a variety of anecdotal cases and pooled institutional summaries which report mid-term results. This manuscript addresses use of cardiac resynchronization and/or multisite pacing in children in the acute postoperative period with a failing right, left, or single ventricle.

Assessment of global and regional left ventricular function after surgical revascularization in patients with coronary artery disease by real-time triplane echocardiography

OBJECTIVE

The purpose of this study was to evaluate the capability of real-time triplane echocardiography (RT3PE) for monitoring global and regional systolic function of the left ventricle (LV) after surgical revascularization and for evaluating the effect of surgery and predicting restenosis.

METHODS

Forty-nine patients underwent RT3PE before and at 10 days and 1, 3, and 6 months after coronary artery bypass grafting (CABG). The global systolic function of the LV was assessed with the parameters of end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), and stroke volume (SV). The regional myocardial deformation was detected by triplane strain rate imaging. Recovery of myocardial function after surgery and the correlation between global and regional function were investigated.

RESULTS

In 41 of the 49 patients, the EDV and ESV decreased, and the EF and SV increased gradually and showed statistical significance at 3 and 6 months after surgery (P < .05; P < .01). The systolic strain rate (SR(sys)) and systolic strain (S(sys)) increased, and the postsystolic strain index (PSI) decreased progressively after CABG, with significant changes in almost all studied segments at 6 months (P < .05; P < .01). In addition, recovery of the SR(sys), S(sys), and PSI at each follow-up stage after surgery correlated well with EF improvement, with a positive correlation between the SR(sys), S(sys), and EF and a negative correlation between the PSI and EF. Restenosis was suspected in the other 8 patients. The sensitivity, specificity, and accuracy of RT3PE to predict restenosis were 75.00%, 89.47%, and 85.19%, respectively.

CONCLUSIONS

Real-time triplane echocardiography can be used to quantitatively assess global and regional myocardial function. It may represent a new, powerful method to monitor improvement of myocardial function after CABG and to predict restenosis.

Analysis of the origin of cardiac wall motion that constitutes myocardial velocity-time curves in patients with left bundle branch block

Septal and lateral wall myocardial velocity-time curves from tissue Doppler imaging were analyzed to determine wall motion from which the velocity originated in 34 patients with left bundle branch and systolic dysfunction (ejection fraction < 45%). Longitudinal strain rate by speckle tracking imaging was assessed to identify whether corresponding wall motion was active or passive. All lateral peak velocities during the ejection period were derived from delayed active movement. However, septal peak velocities were more numerous and complex. Septal peak velocities during pre-ejection were derived from the first active movement in 29 patients (85.2%). Septal peak velocities during the ejection period were derived from the second active movement in 20 patients, passive movement in 9 patients, and first active movement in 5 patients. Because septal peak velocities were consistent with various wall motion types, identification of the origin of septal peak velocities, including during pre-ejection, may be important in identifying LV dyssynchrony based on the propagation of first active myocardial movements.

Tissue Doppler strain-mapping in the assessment of the extent of chronic myocardial infarction: validation using magnetic resonance imaging

AIMS

The distribution of myocardial strain values can be visualized by colour-coded strain images. We examined for the first time if this strain-mapping function can be used to study the extent of prior myocardial infarction.

METHODS AND RESULTS

Echocardiography and cardiac magnetic resonance imaging with delayed contrast enhancement were performed in 26 patients with chronic myocardial infarction. Two-dimensional strain images of the left ventricle were obtained in all standard apical views. Myocardial segments (n = 416) were assigned a score ranging from one to four based on the strain-coded colour of the segment, with higher scores representing worse myocardial function. Strain-mapping scores and quantitative strain values averaged, respectively, 1.3 +/- 0.6 and -16.4 +/- 7.6% in segments without infarction, 1.7 +/- 1.0 and -15.0 +/- 8.6% in non-transmural infarctions, and 2.8 +/- 1.2 and -6.5 +/- 8.6% in transmural infarctions. Strain-mapping had a sensitivity of 60% and a specificity of 95% in detecting segments with transmural myocardial infarction. Corresponding values for echocardiographic wall motion analysis were 50 and 96%. Strain-mapping was possible in 80% of the segments and inter-observer agreement was substantial (kappa = 0.63).

CONCLUSION

Strain-mapping is a clinically applicable method for the assessment of regional myocardial function in post-myocardial infarction patients. Strain-mapping has reasonable feasibility and is more sensitive in detecting infarction damage than routine wall motion analysis.

Early Detection of Regional Myocardial Dysfunction in Paced Children With Congenital Complete Atrioventricular Block

BACKGROUND

Right ventricular apical pacing leads to global left ventricular dysfunction. Assessment of regional myocardial function may allow for earlier detection of pacing-induced myocardial remodeling. The aim of this study was to evaluate regional myocardial function in paced children with congenital complete atrioventricular block (CCAVB).

METHODS

We investigated regional myocardial function using strain echocardiography and tissue velocity imaging in 10 paced children with CCAVB and in 14 age-matched healthy children. Echocardiograms of the paced children were obtained during intrinsic junctional rhythm.

RESULTS

All patients had normal biventricular size and global function. The time from R wave to peak regional strain rate and the time from R wave to peak regional myocardial tissue velocity were measured in nine segments. The differences between maximum and minimum values were used as a measure of contraction delay (dSR and dTV). Study group patients had significantly higher dSR and dTV values compared to the control group. Mean peak strain rates and peak tissue velocities obtained from same segments were significantly decreased in the study group compared to the control group. Regional dysfunction was more prominent in the areas of ventricular pacing. No significant correlation is found between the duration of pacing (2.5-18 years) and dSR, dTV, mean peak strain rates, or mean peak tissue velocities.

CONCLUSION

Pacing leads to regional myocardial dysfunction that can be detected with strain echocardiography and tissue velocity imaging during intrinsic junctional rhythm in children with CCAVB. Pacing-induced regional myocardial remodeling does not seem to progress with long-term right ventricular pacing in children with CCAVB.

Assessment of ischemic myocardium by strain-rate imaging during adenosine stress echocardiography

OBJECTIVE

Strain rate (SR) provides a quantitative segmental analysis of myocardial function. However, the use of SR with stress echocardiography to determine the ischemic myocardium has not been completely investigated. The present study aimed to determine the changes in systolic function of the ischemic myocardium by strain-rate imaging (SRI) with adenosine stress echocardiography.

METHODS

Stenosis and complete occlusion of coronary arteries were produced in 11 canine models by constricting the left anterior descending coronary artery (LAD). Myocardial longitudinal strain with adenosine was measured at baseline and during ischemia and infarction.

RESULTS

Strain and SR did not differ during ischemia and infarction as compared with that at baseline in non-LAD segments or after adenosine treatment. As compared with baseline, during ischemia, LAD segments showed significantly decreased peak systolic SR (SR(peak sys)) (P < 0.05) and significantly increased ratio of postsystolic strain (epsilon(ps)) to strain during ejection time (epsilon(et)) (epsilon(ps)/epsilon(et)) (P < 0.05); epsilon(max) and epsilon(et) were reduced slightly, epsilon(ps) and the ratio of epsilon(ps) to maximal systolic strain (epsilon(max))(epsilon(ps)/epsilon(max)) were increased minimally, but had no significance(P > 0.05). During infarction, the epsilon(ps) and the ratios of epsilon(ps)/epsilon(max) and epsilon(ps)/epsilon(et) were increased markedly (P < 0.01) and epsilon(et) and SR(peak sys) decreased as compared with that at baseline and during ischemia, whereas epsilon(max) was reduced only with at baseline (P < 0.01). After adenosine treatment, in the non-LAD segments, the values of strain and SR did not change at baseline or during ischemia and infarction and in LAD segments, values did not change at baseline and during infarction. However, during ischemia, SR(peak sys) and epsilon(et) were significantly reduced (P < 0.05), whereas epsilon(ps), epsilon(ps)/epsilon(max) and epsilon(ps)/epsilon(et) were increased (P < 0.05 and < 0.01, respectively).

CONCLUSION

Combined with adenosine stress echocardiography, SRI can quantitatively differentiate the ischemic from non-ischemic myocardium. epsilon(ps)/epsilon(max) and epsilon(ps)/epsilon(et) can be used as objective indices to identify the ischemic myocardium.

Usefulness of two-dimensional speckle strain for evaluation of left ventricular diastolic deformation in patients with coronary artery disease

We investigated the influence of > or =70% luminal coronary artery stenosis on regional diastolic deformation at rest using 2-dimensional strain echocardiography. We prospectively imaged patients during/within 24 hours of coronary angiography. Longitudinal systolic (SRs), early (SRe), and late diastolic strain rates, systolic, early, and late diastolic strain and times to isovolumic relaxation and peak SRe were measured in the 3 major vascular territories. Regions subtended by > or =70% coronary stenosis were labeled ischemic. Ischemic regions were compared with the same region in patients without significant coronary stenosis. Of 61 enrolled patients (38 men), 39 had > or =70% coronary stenosis (1 vessel in 14, 2 vessels in 15, 3 vessels in 10), and 15 had normal coronary arteries. There were no significant differences between the normal and ischemic groups with regard to age (59 +/- 13 vs 64 +/- 10 years, p = 0.20), clinical variables (dyslipidemia, smoking, diabetes), systolic (130 +/- 26 vs 139 +/- 31 mm Hg, p = 0.38) or diastolic (72 +/- 13 vs 72 +/- 11 mm Hg, p = 0.81) blood pressure and ejection fraction (58 +/- 12% vs 56 +/- 11%, p = 0.66). SRs and SRe were significantly decreased in ischemic compared with normal regions in all vascular distributions. SRs and SRe together (values below cutoff) or SRe alone were the most specific (93%) and SRe or SRs below cutoff the most sensitive (93%) parameters for detecting ischemic regions. In conclusion, analysis of regional deformation by 2-dimensional strain echocardiography enables detection of significantly diseased coronary arteries at rest. Altered diastolic deformation at rest identifies regions subtended by > or =70% coronary stenosis with high specificity.

Currently available technology for echocardiographic assessment of left ventricular function

New ultrasound technology is mainly represented by tissue Doppler (TD), which allows the quantitative analysis of myocardial function and includes two modalies: pulsed-wave TD and color TD. Strain rate imaging (SRI) is an implementation of color TD. Pulsed-wave TD, performed and analyzed in real time, instantaneously measures myocardial velocities. Color TD, performed offline on digitally stored images, allows the quantification of mean myocardial velocities. The advantage of color TD compared with pulsed TD is the ability to simultaneously analyze multiple myocardial segments. The limit of both these methodologies consists of the myocardial velocity dependence by the base-apex myocardial gradient. SRI measures the rate and percentage of myocardial wall deformation. From digitally recorded color TD cine loops containing velocity data from the entire myocardium, SRI can be derived from regional Doppler velocity gradients. Strain rate is relatively load dependent, and, therefore, can be considered a strong index of myocardial contractility. Due to these favorable characteristics, SRI may potentially overcome the limitations of color TD, discriminating between active and merely passive wall motion. A novel technique is the implementation of 2D SRI, which is not angle dependent, and therefore potentially more feasible and reliable.

[Echocardiographic evaluation to select patients for cardiac resynchronization therapy]

Wide QRS complex and asynchronous myocardial contraction in heart failure are associated with poor prognosis. Resynchronization can be achieved by biventricular pacing (BVP), which leads to hemodynamic and clinical improvement and reverse remodeling, and may improve survival. However, there is a substantial subset of patients with wide QRS complexes in the electrocardiogram who does not improve despite BVP, and there are findings which suggest that resynchronization therapy may be also beneficial for heart failure patients with normal QRS duration. QRS width predicts the benefit of BVP only with limitation and only correlates weakly with echocardiographically determined myocardial asynchrony. Determination of asynchrony by tissue Doppler echocardiography seems to be the best predictor for improvement after BVP, although no consensus on the optimal method to assess asynchrony has yet been achieved. To date, most studies evaluating tissue Doppler echo in BVP were performed retrospectively and only one prospective study with patient selection for BVP according to echocardiography and electrocardiography criteria of asynchrony has been published. These new echocardiographic tools will help to prospectively select patients for BVP, help to guide implantation and to optimize device programming.

Influence of the atrio-ventricular delay optimization on the intra left ventricular delay in Cardiac Resynchronization Therapy

BACKGROUND

Cardiac Resynchronization Therapy (CRT) leads to a reduction of left-ventricular dyssynchrony and an acute and sustained hemodynamic improvement in patients with chronic heart failure. Furthermore, an optimized AV-delay leads to an improved myocardial performance in pacemaker patients. The focus of this study is to investigate the acute effect of an optimized AV-delay on parameters of dyssynchrony in CRT patients.

METHOD

11 chronic heart failure patients with CRT who were on stable medication were included in this study. The optimal AV-delay was defined according to the method of Ismer (mitral inflow and trans-oesophageal lead). Dyssynchrony was assessed echocardiographically at three different settings: AVDOPT; AVDOPT-50 ms and AVDOPT+50 ms. Echocardiographic assessment included 2D- and M-mode echo for the assessment of volumes and hemodynamic parameters (CI, SV) and LVEF and tissue Doppler echo (strain, strain rate, Tissue Synchronisation Imaging (TSI) and myocardial velocities in the basal segments)

RESULTS

The AVDOPT in the VDD mode (atrially triggered) was 105.5 +/- 38.1 ms and the AVDOPT in the DDD mode (atrially paced) was 186.9 +/- 52.9 ms. Intra-individually, the highest LVEF was measured at AVDOPT. The LVEF at AVDOPT was significantly higher than in the AVDOPT-50 setting (p = 0.03). However, none of the parameters of dyssynchrony changed significantly in the three settings.

CONCLUSION

An optimized AV delay in CRT patients acutely leads to an improved systolic left ventricular ejection fraction without improving dyssynchrony.

Tissue Doppler echocardiography and biventricular pacing in heart failure: patient selection, procedural guidance, follow-up, quantification of success

Asynchronous myocardial contraction in heart failure is associated with poor prognosis. Resynchronization can be achieved by biventricular pacing (BVP), which leads to clinical improvement and reverse remodeling. However, there is a substantial subset of patients with wide QRS complexes in the electrocardiogram that does not improve despite BVP. QRS width does not predict benefit of BVP and only correlates weakly with echocardiographically determined myocardial asynchrony. Determination of asynchrony by Tissue Doppler echocardiography seems to be the best predictor for improvement after BVP, although no consensus on the optimal method to assess asynchrony has been achieved yet. Our own preliminary results show the usefulness of Tissue Doppler Imaging and Tissue Synchronization Imaging to document acute and sustained improvement after BVP. To date, all studies evaluating Tissue Doppler in BVP were performed retrospectively and no prospective studies with patient selection for BVP according to echocardiographic criteria of asynchrony were published yet. We believe that these new echocardiographic tools will help to prospectively select patients for BVP, help to guide implantation and to optimize device programming.