Strain-rate imaging during dobutamine stress echocardiography provides objective evidence of inducible ischemia

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.

Association of postsystolic shortening on stress echocardiography and significant coronary artery stenosis: A single-centre retrospective cohort study

BACKGROUND

Postsystolic shortening (PSS) is one of the proposed quantitative measures to predict myocardial ischaemia in the stress echocardiographic (SE) evaluation. It is previously known that hypo-/akinesia (HA) correlates well with coronary stenosis. However, some patients undergoing SE only present with PSS, and their risk of significant coronary stenosis is less clear. This study aimed to evaluate the association between PSS and significant coronary stenosis compared with HA.

METHODS

This was a retrospective cohort study at the hospital of S:t Görans, Stockholm, Sweden. All patients who underwent SE to investigate inducible ischaemia between 1 January 2018 and 15 October 2021 were eligible for inclusion. Exclusion criteria were normal SE and inconclusive test. Pathological SE were divided into two groups, patients with HA and those with PSS. Outcome was significant coronary artery stenosis visualized by invasive coronary angiography.

RESULTS

The final study population consisted of 108 patients (73 PSS, 35 HA). The presence of HA was associated with a higher risk of significant stenosis compared to those with PSS (63% vs. 23%, p < 0.001). This relationship was observed among males (p < 0.001), but not among females (p = 0.133). Nonsignificant stenosis trended to be more common among patients with PSS (21% vs. 6%, p = 0.053) CONCLUSIONS: The finding of PSS without HA was associated with a lower risk of significant coronary stenosis than HA. However, patients with PSS still often had nonsignificant coronary stenosis and PSS in the evaluation for nonobstructive coronary artery disease (CAD) should be further investigated.

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.

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.

New Non-Invasive Imaging Technologies in Cardiac Transplant Follow-Up: Acquired Evidence and Future Options

Heart transplantation (HT) is the established treatment for end-stage heart failure, significantly enhancing patients' survival and quality of life. To ensure optimal outcomes, the routine monitoring of HT recipients is paramount. While existing guidelines offer guidance on a blend of invasive and non-invasive imaging techniques, certain aspects such as the timing of echocardiographic assessments and the role of echocardiography or cardiac magnetic resonance (CMR) as alternatives to serial endomyocardial biopsies (EMBs) for rejection monitoring are not specifically outlined in the guidelines. Furthermore, invasive coronary angiography (ICA) is still recommended as the gold-standard procedure, usually performed one year after surgery and every two years thereafter. This review focuses on recent advancements in non-invasive and contrast-saving imaging techniques that have been investigated for HT patients. The aim of the manuscript is to identify imaging modalities that may potentially replace or reduce the need for invasive procedures such as ICA and EMB, considering their respective advantages and disadvantages. We emphasize the transformative potential of non-invasive techniques in elevating patient care. Advanced echocardiography techniques, including strain imaging and tissue Doppler imaging, offer enhanced insights into cardiac function, while CMR, through its multi-parametric mapping techniques, such as T1 and T2 mapping, allows for the non-invasive assessment of inflammation and tissue characterization. Cardiac computed tomography (CCT), particularly with its ability to evaluate coronary artery disease and assess graft vasculopathy, emerges as an integral tool in the follow-up of HT patients. Recent studies have highlighted the potential of nuclear myocardial perfusion imaging, including myocardial blood flow quantification, as a non-invasive method for diagnosing and prognosticating CAV. These advanced imaging approaches hold promise in mitigating the need for invasive procedures like ICA and EMB when evaluating the benefits and limitations of each modality.

Cardioprotective Effect of Acute Intradialytic Exercise: A Comprehensive Speckle-Tracking Echocardiography Analysis

SIGNIFICANCE STATEMENT

Hemodialysis (HD) can lead to acute left ventricular (LV) myocardial wall motion abnormalities (myocardial stunning) due to segmental hypoperfusion. Exercise during dialysis is associated with favorable effects on central hemodynamics and BP stability, factors considered in the etiology of HD-induced myocardial stunning. In a speckle-tracking echocardiography analysis, the authors explored effects of acute intradialytic exercise (IDE) on LV regional myocardial function in 60 patients undergoing HD. They found beneficial effects of IDE on LV longitudinal and circumferential function and on torsional mechanics, not accounted for by cardiac loading conditions or central hemodynamics. These findings support the implementation of IDE in people with ESKD, given that LV transient dysfunction imposed by repetitive HD may contribute to heart failure and increased risk of cardiac events in such patients.

BACKGROUND

Hemodialysis (HD) induces left ventricular (LV) transient myocardial dysfunction. A complex interplay between linear deformations and torsional mechanics underlies LV myocardial performance. Although intradialytic exercise (IDE) induces favorable effects on central hemodynamics, its effect on myocardial mechanics has never been comprehensively documented.

METHODS

To evaluate the effects of IDE on LV myocardial mechanics, assessed by speckle-tracking echocardiography, we conducted a prospective, open-label, two-center randomized crossover trial. We enrolled 60 individuals with ESKD receiving HD, who were assigned to participate in two sessions performed in a randomized order: standard HD and HD incorporating 30 minutes of aerobic exercise (HDEX). We measured global longitudinal strain (GLS) at baseline (T0), 90 minutes after HD onset (T1), and 30 minutes before ending HD (T2). At T0 and T2, we also measured circumferential strain and twist, calculated as the net difference between apical and basal rotations. Central hemodynamic data (BP, cardiac output) also were collected.

RESULTS

The decline in GLS observed during the HD procedure was attenuated in the HDEX sessions (estimated difference, -1.16%; 95% confidence interval [95% CI], -0.31 to -2.02; P = 0.008). Compared with HD, HDEX also demonstrated greater improvements from T0 to T2 in twist, an important component of LV myocardial function (estimated difference, 2.48°; 95% CI, 0.30 to 4.65; P = 0.02). Differences in changes from T0 to T2 for cardiac loading and intradialytic hemodynamics did not account for the beneficial effects of IDE on LV myocardial mechanics kinetics.

CONCLUSIONS

IDE applied acutely during HD improves regional myocardial mechanics and might warrant consideration in the therapeutic approach for patients on HD.

Strain Rate Changes during Stress Echocardiography Are the Most Accurate Predictors of Significant Coronary Artery Disease in Patients with Previously Treated Acute Coronary Syndrome

BACKGROUND AND AIMS

Dobutamine stress echocardiography (DSE) is a well-established non-invasive investigation for the detection of ischemic myocardial dysfunction. The aim of this study was to evaluate the accuracy of myocardial deformation parameters measured by speckle tracking echocardiography (STE) in predicting culprit coronary artery lesions in patients with prior revascularization and acute coronary syndrome (ACS).

METHODS

We prospectively studied 33 patients with ischemic heart disease, a history of at least one episode of ACS and prior revascularization. All patients underwent a complete stress Doppler echocardiographic examination, including the myocardial deformation parameters of peak systolic strain (PSS), peak systolic strain rate (SR) and wall motion score index (WMSI). The regional PSS and SR were analyzed for different culprit lesions.

RESULTS

The mean age of patients was 59 ± 11 years and 72.7% were males. At peak dobutamine stress, the change in regional PSS and SR in territories supplied by the LAD showed smaller increases compared to those in patients without culprit LAD lesions (p < 0.05 for all). Likewise, the regional parameters of myocardial deformation were reduced in patients with culprit LCx lesions compared to those with non-culprit LCx lesions and in patients with culprit RCA legions compared to those with non-culprit RCA lesions (p < 0.05 for all). In the multivariate analysis, the △ regional PSS (1.134 (CI = 1.059-3.315, p = 0.02)) and the △ regional SR (1.566 (CI = 1.191-9.013, p = 0.001)) for LAD territories predicted the presence of LAD lesions. Similarly, in a multivariable analysis, the △ regional PSS and the △SR predicted LCx culprit lesions and RCA culprit lesions (p < 0.05 for all). In an ROC analysis, the PSS and SR had higher accuracies compared to the regional WMSI in predicting culprit lesions. A △ regional SR of -0.24 for the LAD territories was 88% sensitive and 76% specific (AUC = 0.75; p < 0.001), a △ regional PSS of -1.20 was 78% sensitive and 71% specific (AUC = 0.76, p < 0.001) and a △ WMSI of -0.35 was 67% sensitive and 68% specific (AUC = 0.68, p = 0.02) in predicting LAD culprit lesions. Similarly, the △ SR for LCx and RCA territories had higher accuracies in predicting LCx and RCA culprit lesions.

CONCLUSIONS

The myocardial deformation parameters, particularly the change in regional strain rate, are the most powerful predictors of culprit lesions. These findings strengthen the role of myocardial deformation in increasing the accuracy of DSE analyses in patients with prior cardiac events and revascularization.

Assessment of Postsystolic Shortening and Global Longitudinal Strain Improves the Sensitivity of Dobutamine Stress Echocardiography in End-Stage Liver Disease

BACKGROUND

Dobutamine stress echocardiography (DSE) remains a widely used method for detection of coronary artery disease (CAD) in patients with end-stage liver disease (ESLD) despite low sensitivity. Speckle-tracking assessment of strain may enhance the sensitivity of DSE in the general population, but the value of strain analysis in ESLD is unknown.

METHODS

Dobutamine stress echocardiography with two-dimensional speckle-tracking and quantitative coronary angiography were performed in 146 patients with ESLD. Thirty-six patients (25%) had CAD (≥50% diameter stenosis of a major vessel). Global longitudinal strain at rest (GLSr) and at peak stress (GLSp) and an index of postsystolic (PSSi) shortening ([maximal extent of shortening - extent of shortening in systole]/[extent of shortening in systole]) were determined. A PSSi of ≥ 0.25 was considered evidence for CAD. Receiver operating characteristic analysis was used to determine the optimal thresholds of GLSr and GLSp for CAD and to assess the diagnostic performance of visual assessment of wall motion (WMA) and strain parameters. The sensitivity and specificity of WMA, GLSr, GLSp, and PSSi were compared.

RESULTS

Thirty-six patients (25%) had significant CAD. The areas under the curve for WMA, GLSr, GLSp, and PSSi were 0.60, 0.72, 0.68, and 0.78, respectively. Visual assessment of wall motion had a sensitivity of 28%. The sensitivity of each of the strain parameters, GLSr (53%, P = .016), GLSp (69%, P = .004), and PSSi (78%, P < .001), exceeded the sensitivity for WMA. Visual assessment of wall motion specificity was 92%, which exceeded the specificity for each of the strain parameters (GLSr = 82%, P = .037; GLSp = 63%, P < .001; and PSSi =78%, P = .009). Of the strain parameters, PSSi had the best balance between sensitivity and specificity (both 78%).

CONCLUSION

Assessment of GLS and PSSi with DSE yields better sensitivity than WMA in ELSD patients. Index of postsystolic shortening had the best diagnostic performance of all parameters in this population with a low prevalence of CAD.

Comparison between Visual Assessment and Longitudinal Strain during Dobutamine Stress Echocardiography

Background

The relationship between visual assessment and longitudinal strain during dobutamine stress echocardiography (DSE) remains poorly investigated. This study assessed wall motion segments visually graded as normokinetic, hypokinetic, and akinetic at baseline and the peak of DSE and compared with longitudinal strain between segments with and without induced impaired contractility and improved contractility during DSE.

Methods

This study included 112 patients examined by DSE, consisting of 58 patients referred for diagnostic study and 54 patients referred for viability study. Regional left ventricular (LV) contractility was assessed visually and longitudinal strain was measured using echocardiography transthoracic.

Results

At baseline, the strain of LV segments was -16.33 ± 6.26 in visually normokinetic, 13.05 ± 6.44 in visually hypokinetic, and -8.46 ± 5.69 in visually akinetic segments. During peak dose, the strain of LV segments was -15.37 ± 6.89 in visually normokinetic, -11.37 ± 5.11 in visually hypokinetic, and -7.37 ± 3.92 in visually akinetic segments. In segments with visually observed impaired contractility, the median longitudinal strain was significantly lower than in segments without impaired contractility. For segments with visually observed improved contractility, the median longitudinal strain was significantly higher than for segments without improved contractility. In diagnostic study, sensitivity of visual assessment for absolute decrease of >2% longitudinal strain was 77%, respectively. In the viability study, the sensitivity was 82% for an absolute decrease of ≥2% longitudinal strain.

Conclusions

There is good association between strain analysis value and visually assessed wall motion contractility.

The basic heart anatomy and physiology from the cardiologist's perspective: Toward a better understanding of left ventricular mechanics, systolic, and diastolic function

A comprehensive understanding of the cardiac structure-function relationship is essential for proper clinical cardiac imaging. This review summarizes the basic heart anatomy and physiology from the perspective of a heart imager focused on myocardial mechanics. The main issues analyzed are the left ventricular (LV) architecture, the LV myocardial deformation through the cardiac cycle, the LV diastolic function basic parameters and the basic parameters of the LV deformation used in clinical practice for the LV function assessment.

High-Frame-Rate Speckle Tracking for Echocardiographic Stress Testing

Stress echocardiography helps to diagnose cardiac diseases that cannot easily be detected or do not even manifest at rest. In clinical practice, assessment of the stress test is usually performed visually and, therefore, in a qualitative and subjective way. Although speckle tracking echocardiography (STE) has been proposed for the quantification of function during stress, its time resolution is inadequate at high heart rates. Recently, high-frame-rate (HFR) imaging approaches have been proposed together with dedicated STE algorithms capable of handling small interframe displacements. The aim of this study was to determine if HFR STE is effective in assessing strain and strain rate parameters during echocardiographic stress testing. Specifically, stress echocardiography, at four different workload intensities, was performed in 25 healthy volunteers. At each stress level, HFR images from the apical four-chamber view were recorded using the ULA-OP 256 experimental scanner. Then, the myocardium was tracked with HFR STE, and strain and strain rate biomarkers were extracted to further analyze systolic and diastolic (early and late) peaks, as well as a short-lived isovolumic relaxation peak during stress testing. The global systolic strain response was monophasic, revealing a significant (p < 0.001) increase at low stress but then reaching a plateau. In contrast, all strain rate indices linearly increased (p < 0.001) with increasing stress level. These findings are in line with those reported using tissue Doppler imaging and, thus, indicate that HFR STE can be a useful tool in assessing cardiac function during stress echocardiography.

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.

Diagnostic value of postsystolic shortening of the left ventricular myocardium assessed during speckle tracking stress echocardiography on the treadmill in patients with coronary artery disease

Aim      To evaluate the diagnostic capacity of left ventricular (LV) postsystolic shortening (PSS) values obtained by speckle-tracking stress-echocardiography (stress-EchoCG) using a treadmill test in determining the functional significance of the degree of coronary artery (CA) stenosis.Material and methods  The study included 132 patients (80 men aged 65.0±9.3 years) with suspected or previously verified diagnosis of ischemic heart disease. Stress-EchoCG with the treadmill test was performed for all patients. Strain parameters were determined by two-dimensional speckle-tracking on gray-scale images before and after the exercise. Values of LV postsystolic index (PSI) and LV mean postsystolic time (PST) were calculated. Coronary angiography was performed for all patients. Patients were divided into 3 groups based on the severity of CA stenosis according to the G. G. Gensini score.Results LV PSS values at rest did not significantly differ between the patient groups. After completion of the exercise, the mean LV PSI was significantly higher for patients with pronounced CA stenosis than in the group without CA stenosis or with moderate CA stenosis: 8.9 %  [3.8; 10.7 %] vs. 3.8 % [2.2; 6.8 %] (p=0.012) and 3.4 %  [2.2; 6.2 %] (p=0.012), respectively. The mean LV PSI after completion of the exercise indicated the presence of pronounced CA stenosis with a sensitivity of 75 % and a specificity of 61 % (area under the curve, AUC, 0.74±0.06; р&lt;0.001). After completion of the exercise, the mean LV PST was significantly greater for patients with pronounced CA stenosis than in the group without CA stenosis or with moderate CA stenosis: 27.4 [18.7; 34.7] ms vs. 18.4 [10.8; 26.5] ms (p=0.036) and 20.9 [14.2; 29.5] ms (p=0.036), respectively. The mean LV PST after completion of the exercise exceeding 23.5 ms suggests pronounced CA stenosis with a sensitivity of 71 % and a specificity of 65 % (AUC 0.69±0.06; p=0.004). A complex evaluation of the LV PSI, the LV local contractility disorder (LCD) index, the LV PST, and LV LCD index allows enhancement of the test sensitivity in diagnozing pronounced CA stenosis.Conclusion      Determination of LV PSS in speckle-tracking stress-EchoCG may be useful for evaluating the functional significance of the degree of CA stenosis to enhance the sensitivity of stress-EchoCG in patients with pronounced CA stenosis.

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.

Fast-Strain Encoded Cardiac Magnetic Resonance During Vasodilator Perfusion Stress Testing

Background: Cardiac magnetic resonance perfusion imaging during vasodilator stress is an established modality in patients with suspected and known coronary artery disease (CAD). Aim: This study aimed to evaluate the performance of fast-Strain-Encoded-MRI (fast-SENC) for the diagnostic classification and risk stratification of patients with ischemic heart disease. Methods: Perfusion and fast-SENC cardiac magnetic resonance (CMR) images were retrospectively analyzed in 111 patients who underwent stress CMR. The average myocardial perfusion score index, global and segmental longitudinal and circumferential strain (GLS and GCS and SLS and SCS, respectively), were measured at rest and during stress. The combination of SLS and SCS was referred to as segmental aggregate strain (SAS). Segments exhibiting perfusion defects or SAS impairment during stress were defined as "ischemic." All-cause mortality, non-fatal infarction, and urgent revascularization were deemed as our combined clinical endpoint. Results: During adenosine stress testing, 44 of 111 (39.6%) patients exhibited inducible perfusion abnormalities. During a mean follow-up of 1.94 ± 0.65 years, 25 (22.5%) patients reached the combined endpoint (death in n = 2, infarction in n = 3 and urgent revascularization in n = 20). Inducible perfusion defects were associated with higher number of segments with inducible SAS reduction ≥6.5% (χ² = 37.8, AUC = 0.79, 95% CI = 0.71-0.87, p < 0.001). In addition, patients with inducible perfusion defects or SAS impairment exhibited poorer outcomes (AUC_Perf = 0.81 vs. AUC_SAS = 0.74, p = NS vs. each other, and χ² = 30.8, HR = 10.3 and χ² = 9.5, HR = 3.5, respectively, p < 0.01 for both). Conclusion: Purely quantitative strain analysis by fast-SENC during vasodilator stress was related to the diagnosis of ischemia by first-pass perfusion and is non-inferior for the risk stratification of patients with ischemic heart disease. This may bear clinical implications, especially in patients with contraindications for contrast agent administration.

A Reminder That Stress Echocardiography Is Useful in Diagnosing Myocardial Ischemia in Nonobstructive Coronary Artery Disease: Case Series

Identification of ischemia remains critical when assessing individuals presenting with atypical symptoms or in patients with known coronary artery disease (CAD). Several imaging modalities are currently available to attain this diagnostic goal. Unfortunately, not all case presentations are straightforward, particularly when microvascular dysfunction (MVD) is the cause of symptoms in the absence of identifiable epicardial luminal stenosis. Specifically, in such cases, current imaging guidelines do not include stress echocardiography (SE) as a recommended tool when assessing these patients. We present three cases that highlight the utility of SE for identifying MVD and provide mechanistic explanations. We believe that SE should not be completely discarded as an inadequate testing modality; we highlight the potential utility of this imaging modality not only in diagnosing CAD and pre-surgical evaluation of patients but also in identifying patients with MVD.

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.

Acute regional changes in myocardial strain may predict ventricular remodelling after myocardial infarction in a large animal model

To identify predictors of left ventricular remodelling (LVR) post-myocardial infarction (MI) and related molecular signatures, a porcine model of closed-chest balloon MI was used along with serial cardiac magnetic resonance imaging (CMRI) up to 5-6 weeks post-MI. Changes in myocardial strain and strain rates were derived from CMRI data. Tissue proteomics was compared between infarcted and non-infarcted territories. Peak values of left ventricular (LV) apical circumferential strain (ACS) changed over time together with peak global circumferential strain (GCS) while peak GLS epicardial strains or strain rates did not change over time. Early LVR post-MI enhanced abundance of 39 proteins in infarcted LV territories, 21 of which correlated with LV equatorial circumferential strain rate. The strongest associations were observed for D-3-phosphoglycerate dehydrogenase (D-3PGDH), cysteine and glycine-rich protein-2, and secreted frizzled-related protein 1 (sFRP1). This study shows that early changes in regional peak ACS persist at 5-6 weeks post-MI, when early LVR is observed along with increased tissue levels of D-3PGDH and sFRP1. More studies are needed to ascertain if the observed increase in tissue levels of D-3PGDH and sFRP1 might be casually involved in the pathogenesis of adverse LV remodelling.

Prediction of Significant Coronary Artery Disease Through Advanced Echocardiography: Role of Non-invasive Myocardial Work

Background: Non-invasive prediction of critical coronary artery stenosis (CAST) in patients with coronary artery disease (CAD) is challenging. Strain parameters can often capture an impairment of regional longitudinal function; however, they are load dependent. A novel non-invasive method to estimate Myocardial Work (MW) has been recently proposed, showing a strong correlation with invasive work measurements. Our aim was to investigate the ability of non-invasive MW to predict the ischaemic risk area underlying a CAST. Methods and Results: The study population comprises 80 individuals: 50 patients with CAST and 30 controls (CTRL). Echocardiography recordings were obtained before coronary angiography to measure global longitudinal strain (GLS), Myocardial Work Index (MWI), Myocardial Constructive Work (MCW), Myocardial Wasted work (MWW), Myocardial Work Efficiency (MWE). Global MWI (p = 0.048), MWE (p < 0.001), and MCW (p = 0.048) at baseline were significantly reduced in patients with CAST compared to controls (p < 0.05). Regional MWE within the myocardial segments underlying the CAST, but not LS, was significantly reduced compared to non-target segments (p < 0.001). At ROC analysis, the diagnostic performance to predict CAST for regional MWE (AUC = 0.920, p < 0.001) was higher compared to both regional post-systolic shortening index (PSI) (AUC = 0.600, p = 0.129) and regional LS (AUC = 0.546, p = 0.469). Conclusions: Non-invasive estimation of MW work indices is able to predict a CAST before invasive angiography.

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.

[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.

Comparison of the within-reader and inter-vendor agreement of left ventricular circumferential strains and volume indices derived from cardiovascular magnetic resonance imaging

PURPOSE

Volume indices and left ventricular ejection fraction (LVEF) are routinely used to assess cardiac function. Ventricular strain values may provide additional diagnostic information, but their reproducibility is unclear. This study therefore compares the repeatability and reproducibility of volumes, volume fraction, and regional ventricular strains, derived from cardiovascular magnetic resonance (CMR) imaging, across three software packages and between readers.

METHODS

Seven readers analysed 16 short-axis CMR stacks of a porcine heart. Endocardial contours were manually drawn using OsiriX and Simpleware ScanIP and repeated in both softwares. The images were also contoured automatically in Circle CVI42. Endocardial global, apical, mid-ventricular, and basal circumferential strains, as well as end-diastolic and end-systolic volume and LVEF were compared.

RESULTS

Bland-Altman analysis found systematic biases in contour length between software packages. Compared to OsiriX, contour lengths were shorter in both ScanIP (-1.9 cm) and CVI42 (-0.6 cm), causing statistically significant differences in end-diastolic and end-systolic volumes, and apical circumferential strain (all p<0.006). No differences were found for mid-ventricular, basal or global strains, or left ventricular ejection fraction (all p<0.007). All CVI42 results lay within the ranges of the OsiriX results. Intra-software differences were found to be lower than inter-software differences.

CONCLUSION

OsiriX and CVI42 gave consistent results for all strain and volume metrics, with no statistical differences found between OsiriX and ScanIP for mid-ventricular, global or basal strains, or left ventricular ejection fraction. However, volumes were influenced by the choice of contouring software, suggesting care should be taken when comparing volumes across different software.

Right Ventricular Dysfunction in Early Sepsis and Septic Shock

BACKGROUND

Sepsis is a frequently lethal state, commonly associated with left ventricular (LV) dysfunction. Right ventricular (RV) dysfunction in sepsis is less well understood.

RESEARCH QUESTION

In septic patients, how common is RV dysfunction, and is it associated with worse outcomes?

STUDY DESIGN AND METHODS

We measured echocardiographic parameters on critically ill patients with severe sepsis or septic shock within the first 24 hours of ICU admission. We defined RV dysfunction as fractional area change (FAC) less than 35% or tricuspid annulus systolic plane excursion (TAPSE) less than 1.6 cm. We defined LV systolic dysfunction as ejection fraction (EF) less than 45% or longitudinal strain greater than -19%. Using logistic regression, we assessed the relationship between 28-day mortality and presence of RV dysfunction and LV systolic dysfunction, controlling for receipt of vasopressors, receipt of fluid, mechanical ventilation, and the acute physiology and chronic health evaluation (APACHE II) score.

RESULTS

We studied 393 patients. RV and LV dysfunction were common (48% and 63%, respectively). Mean echocardiographic values were: RV end-diastolic area, 22.4 ± 7.0 cm²; RV end-systolic area, 14.2 ± 6.0 cm²; RV FAC, 38 ± 11%; TAPSE, 1.8 ± .06 cm; RV longitudinal strain, -15.3 ± 6.5%; LV EF, 60% ± 14%; LV longitudinal strain, -16.5% ± 6.0%. Patients with RV dysfunction had higher 28-day mortality (31% vs 16%, P = .001). In our multivariable regression model, RV dysfunction was associated with increased mortality (OR, 3.4; CI, 1.7-6.8; P = .001), and LV systolic dysfunction was not (OR, 0.63; CI, 0.3 -1.2; P = .32) INTERPRETATION: Right ventricular dysfunction is present in nearly half of studied septic patients and is associated with over threefold higher 28-day mortality.

Additional diagnostic accuracy of global longitudinal strain at peak dobutamine stress in patients with moderate pretest probability of coronary artery disease

BACKGROUND

Previous studies confirmed the feasibility of 2D speckle tracking echocardiography (2D STE) during dobutamine stress echocardiography (DSE) in assessing myocardial ischemia in patients with previous myocardial infarction. It is unknown whether it improves the diagnostic accuracy in young patients with intermediate pretest probability for coronary artery disease (CAD) and no prior cardiovascular events.

METHODS

We prospectively studied 101 patients by DSE and STE, followed by coronary angiography within 1 month. Significant CAD was defined as diameter stenosis ≥ 50%. Receiver operating characteristic analysis obtained global longitudinal strain (GLS) cutoff values of significant area under the curve (AUC).

RESULTS

Mean age: 53 ± 8 years, 56% females, 49 had significant CAD (group 1) and 52 had normal/mild CAD (group 2); no significant baseline differences except more males in group 1 (P: .002). DSE sensitivity and specificity for CAD were 79.6% and 92.3%, respectively, positive predictive value (PPV): 90.6%, negative predictive value (NPV): 82.7%, and diagnostic accuracy: 86%. At peak stress, all strain parameters were significantly lower in group 1. However, GLS had the highest AUC: 0.88, P: <.001. GLS cutoff value ≤ -20.5 had 89.8% sensitivity, 84.6% specificity, 84.6% PPV, 89.8% NPV, and 87% diagnostic accuracy. Combining GLS cutoff with DSE had higher AUC than either alone (0.9, P < .001): 95.9% sensitivity, 84.6% specificity, 85.5% PPV, 95.7% NPV, and 90% diagnostic accuracy.

CONCLUSION

2D-STE-derived GLS increases DSE precision to detect CAD in intermediate pretest probability patients: It improves DSE sensitivity, NPV, and accuracy. It is reproducible and has comparable specificity.

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.

Deterioration of longitudinal, circumferential, and radial myocardial strains during acute coronary flow reduction: which direction of strain should be analyzed for early detection?

Longitudinal myocardial strain is considered to deteriorate in the early ischemic stage compared to circumferential and radial strains because the subendocardial inner oblique fibers are generally directed along the longitudinal axis. However, it is unclear whether the decrease in longitudinal strain precedes a decrease in circumferential and radial strains during acute coronary flow reduction. The left anterior descending artery was gradually narrowed in 13 open-chest dogs. Whole-wall and subendocardial longitudinal, circumferential, and radial strains were analyzed at baseline and during flow reduction. Peak systolic and end-systolic strains, the postsystolic strain index (PSI), and the early systolic strain index (ESI) were measured in the risk area; the decreasing rate in each parameter and the diagnostic accuracy to detect flow reduction were evaluated. Absolute values of peak systolic and end-systolic strains gradually decreased with flow reduction. The decreasing rate and diagnostic accuracy of longitudinal systolic strain were not significantly different from those in other strains, although the diagnostic accuracy of radial systolic strain tended to be lower. PSI and ESI gradually increased with flow reduction. In these parameters, a lower diagnostic accuracy with respect to radial strain was not demonstrated. During acute coronary flow reduction, the decrease in longitudinal systolic strain did not precede that in circumferential systolic strain; however, the decrease in radial systolic strain may be smaller than that of other systolic strains. In contrast, there appeared to be no differences in the PSI and ESI values among the three strains.

Analysis of nonstandardized stress echocardiography sequences using multiview dimensionality reduction

Alternative stress echocardiography protocols such as handgrip exercise are potentially more favorable towards large-scale screening scenarios than those currently adopted in clinical practice. However, these are still underexplored because the maximal exercise levels are not easily quantified and regulated, requiring the analysis of the complete data sequences (thousands of images), which represents a challenging task for the clinician. We propose a framework for the analysis of these complex datasets, and illustrate it on a handgrip exercise dataset including complete acquisitions of 10 healthy controls and 5 ANT1 mutation patients (1377 cardiac cycles). The framework is based on an unsupervised formulation of multiple kernel learning, which is used to integrate information coming from myocardial velocity traces and heart rate to obtain a lower-dimensional representation of the data. Such simplified representation is then explored to discriminate groups of response and understand the underlying pathophysiological mechanisms. The analysis pipeline involves the reconstruction of population-specific signatures using multiscale kernel regression, and the clustering of subjects based on the trajectories defined by their projected sequences. The results confirm that the proposed framework is able to detect distinctive clusters of response and to provide insight regarding the underlying pathophysiology.

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.

Reduced Left Ventricular Global Longitudinal Strain Predicts Prolonged Hospitalization: A Cohort Analysis of Patients Having Aortic Valve Replacement Surgery

BACKGROUND

Left ventricular ejection fraction (LVEF) is often preserved in patients with aortic stenosis and thus cannot distinguish between normal myocardial contractile function and subclinical dysfunction. Global longitudinal strain and strain rate (SR), which measure myocardial deformation, are robust indicators of myocardial function and can detect subtle myocardial dysfunction that is not apparent with conventional echocardiographic measures. Strain and SR may better predict postoperative outcomes than LVEF. The primary aim of our investigation was to assess the association between global longitudinal strain and serious postoperative outcomes in patients with aortic stenosis having aortic valve replacement. Secondarily, we also assessed the associations between global longitudinal SR and LVEF and the outcomes.

METHODS

In this post hoc analysis of data from a randomized clinical trial (NCT01187329), we examined the association between measures of myocardial function and the following outcomes: (1) need for postoperative inotropic/vasopressor support; (2) prolonged hospitalization (>7 days); and (3) postoperative atrial fibrillation. Standardized transesophageal echocardiographic examinations were performed after anesthetic induction. Myocardial deformation was measured using speckle-tracking echocardiography. Multivariable logistic regression was used to assess associations between measures of myocardial function and outcomes, adjusted for potential confounding factors. The predictive ability of global longitudinal strain, SR, and LVEF was assessed as area under receiver operating characteristics curves (AUCs).

RESULTS

Of 100 patients enrolled in the clinical trial, 86 patients with aortic stenosis had acceptable images for global longitudinal strain analysis. Primarily, worse intraoperative global longitudinal strain was associated with prolonged hospitalization (odds ratio [98.3% confidence interval], 1.22 [1.01-1.47] per 1% decrease [absolute value] in strain; P = .012), but not with other outcomes. Secondarily, worse global longitudinal SR was associated with prolonged hospitalization (odds ratio [99.7% confidence interval], 1.68 [1.01-2.79] per 0.1 second(-1) decrease [absolute value] in SR; P = .003), but not other outcomes. LVEF was not associated with any outcomes. Global longitudinal SR was the best predictor for prolonged hospitalization (AUC, 0.72), followed by global longitudinal strain (AUC, 0.67) and LVEF (AUC, 0.62).

CONCLUSIONS

Global longitudinal strain and SR are useful predictors of prolonged hospitalization in patients with aortic stenosis having an aortic valve replacement.

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.

Diabetes as an independent predictor of left ventricular longitudinal strain reduction at rest and during dobutamine stress test in patients with significant coronary artery disease

Aims

Diabetes (DM) is a strong cardiovascular risk factor modifying also the left ventricular (LV) function that may be objectively assessed with echocardiographic strain analysis. Although the impact of isolated DM on myocardial deformation has been already studied, few data concern diabetics with coronary artery disease (CAD), especially in all stages of dobutamine stress echocardiography (DSE). We compared LV systolic function during DSE in CAD with and without DM using state-of-the art speckle-tracking quantification and assessed the impact of DM on LV systolic strain.

Methods and results

DSE was performed in 250 patients with angina who afterwards had coronarography with ≥50% stenosis in the left main artery and ≥70% in other arteries considered as significant. In this analysis, we included 127 patients with confirmed CAD: 42 with DM [DM(+); mean age 64 ± 9 years] and 85 patients without DM [DM(-); mean age 63 ± 9 years]. The severity of CAD and LV ejection fraction (EF) were similar in both groups. Global and regional LV peak systolic longitudinal strain (PSLS) revealed in all DSE phases lower values in DM(+) group: 14.5 ± 3.6% vs. 17.4 ± 4.0% at rest; P = 0.0001, 13.8 ± 3.9% vs. 16.7 ± 4.0% at peak stress; P = 0.0002, and 14.2 ± 3.1% vs. 15.5 ± 3.5% at recovery; P = 0.0432 for global parameters, although dobutamine challenge did not enhance further resting differences. LV EF, body surface area, and diabetes were independent predictors for strain in 16-variable model (R2 = 0, 51, P < 0.001).

Conclusion

PSLS although diminished in both groups with CAD was lower in diabetics at all DSE stages, and DM was an independent predictor of this impairment. However, the dobutamine challenge did not deepen the resting differences, suggesting that the direct impact of coronary stenoses effaces the influence of DM during DSE. The comparison with our previous data revealed synergistic, detrimental effect of coexisting CAD and DM on myocardial strain.

The Clinical Utility and Enduring Versatility of Stress Echocardiography

Stress echocardiography is an established cardiac imaging modality for the detection and quantification of severity of coronary artery disease. In recent years, there has also been an increasing use of stress echocardiography in the assessment of non-ischaemic cardiac disease given its ability to assess functional capacity and haemodynamic changes with exercise which can help guide therapy and inform prognosis. The emerging use of strain, myocardial contrast and three-dimensional (3D) echocardiography further assists in improving diagnostic accuracy particularly in patients with coronary artery disease. This paper summarises the protocols, indications and clinical applications of stress echocardiography in both ischaemic and non-ischaemic cardiac disease.

A Case of Myocardial Ischemia Detected by Global Longitudinal Strain Using Intraoperative Speckle-Tracking Echocardiography in a High-Risk Patient Undergoing Abdominal Aortic Aneurysm Repair

Patient: Male, 75

Final Diagnosis: Coronary artery disease

Symptoms: Chest pain

Medication: —

Clinical Procedure: Open abdominal aortic aneurysm repair

Specialty: Anesthesiology

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.

Effect of elective percutaneous coronary intervention of left anterior descending coronary artery on regional myocardial function using strain imaging

BACKGROUND

Percutaneous coronary intervention (PCI) is a commonly used procedure for revascularization, however the impairment of regional myocardial function in patients with stable coronary artery disease (CAD) has not been well characterized, our study aimed to assess the improvement of left ventricular (LV) systolic function after elective PCI of the left anterior descending artery (LAD) using strain and strain rate imaging techniques.

MATERIALS AND METHODS

The study included 30 patients (aged 56.8 ± 6.6 years, 66.7% males) presented with stable CAD on optimal medical therapy, and recommended for elective PCI to LAD, all patients included in the study had a normal LV wall motions, and normal LV systolic function. Tissue Doppler imaging (TDI) was done before PCI, immediately, and three months post PCI. The peak systolic longitudinal strain (PSLS), and peak systolic strain rate (PSSR) were measured and averaged for the 6 LAD segments (the basal, mid, and apical segments of the anterior wall, the basal, mid anteroseptal, and the apicoseptal segments), 15 healthy control subjects were included as a control group.

RESULTS

The average PSLS and PSSR of the ischemic segments were significantly lower in patients compared to control in the ischemic segments, and significantly increased 3 months post PCI but not immediately post PCI. Using the ROC curve a cutoff value of -13.69% for PSLS can detect regional ischemia with a sensitivity 93.3% and a specificity of 80%.

CONCLUSIONS

TDI derived strain and strain rate can detect resting regional myocardial dysfunction in presence of preserved LV systolic function, and can assess the improvement of regional myocardial function after successful elective PCI in patients with stable CAD.

Accuracy of speckle tracking in the context of stress echocardiography in short axis view: An in vitro validation study

Aim

This study aimed to test the accuracy of a speckle tracking algorithm to assess myocardial deformation in a large range of heart rates and strain magnitudes compared to sonomicrometry.

Methods and results

Using a tissue-mimicking phantom with cyclic radial deformation, radial strain derived from speckle tracking (RS-SpT) of the upper segment was assessed in short axis view by conventional echocardiography (Vivid q, GE) and post-processed with clinical software (EchoPAC, GE). RS-SpT was compared with radial strain measured simultaneously by sonomicrometers (RS-SN). Radial strain was assessed with increasing deformation rates (60 to 160 beats/min) and increasing pulsed volumes (50 to 100 ml/beat) to simulate physiological changes occurring during stress echocardiography. There was a significant correlation (R² = 0.978, P <0.001) and a close agreement (bias ± 2SD, 0.39 ± 1.5%) between RS-SpT and RS-SN. For low strain values (<15%), speckle tracking showed a small but significant overestimation of radial strain compared to sonomicrometers. Two-way analysis of variance did not show any significant effect of the deformation rate. For RS-SpT, the feasibility was excellent and the intra- and inter-observer variability were low (the intraclass correlation coefficients were 0.96 and 0.97, respectively).

Conclusions

Speckle tracking demonstrated a good correlation with sonomicrometry for the assessment of radial strain independently of the heart rate and strain magnitude in a physiological range of values. Though speckle tracking seems to be a reliable and reproducible technique to assess myocardial deformation variations during stress echocardiography, further studies are mandated to analyze the impact of angulated and artefactual out-of-plane motions and inter-vendor variability.

Imaging the myocardial ischemic cascade

Non-invasive imaging plays a growing role in the diagnosis and management of ischemic heart disease from its earliest manifestations of endothelial dysfunction to myocardial infarction along the myocardial ischemic cascade. Experts representing the North American Society for Cardiovascular Imaging and the European Society of Cardiac Radiology have worked together to organize the role of non-invasive imaging along the framework of the ischemic cascade. The current status of non-invasive imaging for ischemic heart disease is reviewed along with the role of imaging for guiding surgical planning. The issue of cost effectiveness is also considered. Preclinical disease is primarily assessed through the coronary artery calcium score and used for risk assessment. Once the patient becomes symptomatic, other imaging tests including echocardiography, CCTA, SPECT, PET and CMR may be useful. CCTA appears to be a cost-effective gatekeeper. Post infarction CMR and PET are the preferred modalities. Imaging is increasingly used for surgical planning of patients who may require coronary artery bypass.

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.

Left ventricular strain rate is reduced during voluntary apnea in healthy humans

During an apneic event, sympathetic nerve activity increases resulting in subsequent increases in left ventricular (LV) afterload and myocardial work. It is unknown how cardiac mechanics are acutely impacted by the increased myocardial work during an apneic event. Ten healthy individuals (23 ± 3 yr) performed multiple voluntary end-expiratory apnea (VEEA) maneuvers exposed to room air, while a subset ( n = 7) completed multiple VEEA exposed to hyperoxic air (100% [Formula: see text]). Beat-by-beat blood pressure, heart rate, and stroke volume were measured continuously. Effective arterial elastance (EA) was calculated as an index of cardiac afterload, and myocardial work was calculated as the rate pressure product (RPP). Tissue Doppler echocardiography was used to measure LV tissue velocities, deformation via strain, and strain rate (SR). Systolic blood pressure (Δ18 ± 13 mmHg, P < 0.01), EA (Δ0.13 ± 0.10 mmHg/ml, P < 0.01), and RPP (Δ9 ± 10 beats/min × mmHg 10^-2, P < 0.01) significantly increased with room air VEEA. This occurred in parallel with decreases in peak longitudinal systolic (Δ-0.62 ± 0.41 cm/s, P < 0.01) and early LV filling (Δ-2.81 ± 1.99 cm/s, P < 0.01) myocardial velocities. Longitudinal SR (Δ-0.30 ± 0.32 1/s, P = 0.01) was significantly decreased during room air VEEA. VEEA with hyperoxia did not alter ( P > 0.18) EA or RPP and attenuated the systolic blood pressure response compared with room air. Myocardial velocities and LV strain rate response to VEEA were unchanged ( P = 0.30) with hyperoxia. Consistent with our hypotheses, VEEA-induced increases in EA and myocardial work impact LV mechanics, which may depend, in part, on stimulation of peripheral chemoreceptors. NEW & NOTEWORTHY Transient increases in arterial blood pressure and systemic vascular resistance occur during sleep apnea events and may contribute to the associated daytime hypertension and risk of overt cardiovascular disease. To date, the link between this apnea pressor response and acute changes in left ventricular function remains poorly understood. We demonstrate that in parallel to increases in cardiac afterload a depressed left ventricular systolic function occurs at end apnea.

Left ventricular endocardial and epicardial strain changes with apical myocardial ischemia in an open-chest porcine model

Early detection of acute myocardial ischemia is critical to prevent permanent myocardial damage. The impact of apical ischemia on global left ventricular (LV) function can be difficult to characterize using traditional volume‐based echocardiography measures. Myocardial strain imaging is a sensitive, quantitative marker of myocardial deformation that can measure ventricular function. Recent advances allow layer‐specific measurement of endo‐ and epicardial strain, enhancing the ability to evaluate myocardial ischemia. This study investigates the effects of apical ischemia on LV function using epi‐ and endocardial strain. We hypothesize that myocardial strain will identify changes in regional and global myocardial function associated with focal apical ischemia as compared to ejection fraction (EF), and that longitudinal strain will be a better indicator of myocardial dysfunction compared to circumferential or radial strain. In a porcine model (n = 9), acute ischemia was induced by left anterior descending coronary artery occlusion. Echocardiograms were performed at baseline, during 15‐min ischemia, and after reperfusion. Global longitudinal strain decreased with acute focal ischemia of the left ventricular apical region (baseline: −16.4% vs. ischemia: −12.2%; P = 0.010), with no change observed in global circumferential and radial strain or EF. Both endocardial and epicardial longitudinal strain decreased by 68% (P < 0.001) in the ischemic and peri‐ischemic zone, while circumferential and radial strain only decreased in endocardium of the ischemic zone. Longitudinal strain was more sensitive to ischemia, being able to detect changes in global LV function and thus may confer clinical diagnostic advantage in the evaluation of acute LV apical ischemia.

Study of the Safety of Extracorporeal Cardiac Shock Wave Therapy: Observation of the Ultrastructures in Myocardial Cells by Transmission Electron Microscopy

Extracorporeal cardiac shock wave therapy (CSWT) has been used to treat patients with severe coronary heart disease and cardiac failure with good results; however, the safety of this treatment is still controversial. Its safety in clinical setting and on microstructures has been confirmed, but the influence of shock wave on the ultrastructures of myocardial cells is not clear. In this study, 12 Sprague-Dawley rats were randomly divided into control (NC) and CSWT therapy (NC+SW) groups. The heart rate, blood pressure, serum troponin I (TNI), and cardiac ultrasound were evaluated, and the myocardial inflammatory responses and fibrosis changes were compared. The samples were observed by transmission electron microscopy to evaluate the changes in myocardial tissue ultrastructure. The CSWT had no significant influence on rat hemodynamics indices and serum TNI, did not affect left ventricular function, and did not cause myocardial inflammatory response and fibrosis changes. The scores of myocardial ultrastructure damage in the NC and NC+SW groups were 1.39 ± 0.982 and 2.42 ± 1.009, respectively ( P = .103). The CSWT did not cause significant additional damage to myocardial ultrastructures. The safety of CWST has been preliminarily proved at the clinical, microstructure, and ultrastructure levels, but its long-term safety needs further exploration.

Early Left and Right Ventricular Response to Aortic Valve Replacement

BACKGROUND

The immediate effect of aortic valve replacement (AVR) for aortic stenosis on perioperative myocardial function is unclear. Left ventricular (LV) function may be impaired by cardioplegia-induced myocardial arrest and ischemia-reperfusion injury, especially in patients with LV hypertrophy. Alternatively, LV function may improve when afterload is reduced after AVR. The right ventricle (RV), however, experiences cardioplegic arrest without benefiting from improved loading conditions. Which of these effects on myocardial function dominate in patients undergoing AVR for aortic stenosis has not been thoroughly explored. Our primary objective is thus to characterize the effect of intraoperative events on LV function during AVR using echocardiographic measures of myocardial deformation. Second, we evaluated RV function.

METHODS

In this supplementary analysis of 100 patients enrolled in a clinical trial (NCT01187329), 97 patients underwent AVR for aortic stenosis. Of these patients, 95 had a standardized intraoperative transesophageal echocardiographic examination of systolic and diastolic function performed before surgical incision and repeated after chest closure. Echocardiographic images were analyzed off-line for global longitudinal myocardial strain and strain rate using 2D speckle-tracking echocardiography. Myocardial deformation assessed at the beginning of surgery was compared with the end of surgery using paired t tests corrected for multiple comparisons.

RESULTS

LV volumes and arterial blood pressure decreased, and heart rate increased at the end of surgery. Echocardiographic images were acceptable for analysis in 72 patients for LV strain, 67 for LV strain rate, and 54 for RV strain and strain rate. In 72 patients with LV strain images, 9 patients required epinephrine, 22 required norepinephrine, and 2 required both at the end of surgery. LV strain did not change at the end of surgery compared with the beginning of surgery (difference: 0.7 [97.6% confidence interval, -0.2 to 1.5]%; P = 0.07), whereas LV systolic strain rate improved (became more negative) (-0.3 [-0.4 to -0.2] s; P < 0.001). In contrast, RV systolic strain worsened (became less negative) at the end of surgery (difference: 4.6 [3.1 to 6.0]%; P < 0.001) although RV systolic strain rate was unchanged (0.0 [97.6% confidence interval, -0.1 to 0.1]; P = 0.83).

CONCLUSIONS

LV function improved after replacement of a stenotic aortic valve demonstrated by improved longitudinal strain rate. In contrast, RV function, assessed by longitudinal strain, was reduced.