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

Comparative analysis of left ventricle function and deformation imaging in short and long axis plane in cardiac magnetic resonance imaging

Background

Advancements in cardiac imaging have revolutionized our understanding of ventricular contraction. While ejection fraction (EF) is still the gold standard parameter to assess left ventricle (LV) function, strain imaging (SI) has provided valuable insights into ventricular mechanics. The lack of an integrative method including SI parameters in a single, validated formula may limit its use. Our aim was to compare different methods for evaluating global circumferential strain (GCS) and their relationship with global longitudinal strain (GLS) and EF in CMR and how the different evaluations fit in the theoretical relationship between EF and global strain.

Methods

Retrospective monocenter study. Inclusion of every patient who underwent a CMR during a 15 months period with various clinical indication (congenital heart defect, myocarditis, cardiomyopathy). A minimum of three LV long-axis planes and a stack of short-axis slices covering the LV using classical steady-state free precession cine sequences. A single assessment of GLS on long axis (LAX) slices and a double assessment of GCS and EF with both short axis (SAX) and LAX slices were made by a single experienced CMR investigator.

Results

GCS-SAX and GCS-LAX were correlated (r = 0.77, P < 0.001) without being interchangeable with a high reproducibility for GCS, GLS and EF. EF calculated from LAX images showed an overestimation compared to EF derived from SAX images of 7%. The correlation between calculated EF and theoretical EF derived from SI was high (r = 0.88 with EF-SAX, 0.95 with EF-LAX).

Data conclusion

This study highlights the need to integrate strain imaging techniques into clinical by incorporating strain parameters into EF calculations, because it gives a deeper understanding of cardiac mechanics.

Incremental value of myocardial global longitudinal strain in predicting major adverse cardiac events among patients with hypertrophic cardiomyopathy

OBJECTIVES

Endocardial global longitudinal strain (endo-GLS) measured with echocardiography (echo) has been demonstrated to be associated with myocardial fibrosis (MF) and is a prognostic predictor in patients with hypertrophic cardiomyopathy (HCM). Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging showed that MF is primarily located in the myocardial layer of the extremely hypertrophic septal or ventricular wall. We hypothesized that GLS of the myocardial layer (myo-GLS) is more strongly correlated with the extent of LGE (%LGE) and is a more powerful prognostic factor than endo-GLS.

METHODS

A total of 177 inpatients (54.0 [IQR: 43.0, 64.0] years, female 37.3%) with HCM were retrospectively included from May 2019 to April 2021. Among them, 162 patients underwent echocardiographic examination and contrast-enhanced CMR within 7 days. Myo-GLS and %LGE were blindly assessed in a core laboratory. All the patients were followed after they were discharged.

RESULTS

During a mean follow-up of 33.77 [IQR 30.05, 35.40] months, 14 participants (7.91%) experienced major adverse cardiac events (MACE). The MACE (+) group showed lower absolute endo-GLS and myo-GLS than the MACE (-) group. Myo-GLS was more associated with %LGE (r = -.68, P < .001) than endo-GLS (r = -.64, P < .001). Cox multivariable analysis indicated that absolute myo-GLS was independently associated with MACE (adjusted hazard ratio = .75, P < .05). Myo-GLS was better than endo-GLS at detecting MACE (+) patients (-8.64%, AUC .939 vs. - 16.375%, AUC .898, P < .05).

CONCLUSIONS

Myo-GLS is a stronger predictor of MACE than endo-GLS in patients with HCM and is highly correlated with %LGE.

Lower Limit of Normality of Segmental Multilayer Longitudinal Strain in Healthy Adult Subjects

Speckle tracking echocardiography is an advanced imaging technique that allows for a more detailed assessment of cardiac global and regional function. Reference values for segmental longitudinal layered strain (subendocardial, mid-myocardial, and subepicardial) are scarce, limiting the clinical use of these measurements in clinical practice. Two hundred consecutive Caucasian healthy subjects (mean age = 37 ± 11 years) were enrolled in the study. The mean values of global longitudinal strain (GLS) for endocardial (Endo), mid-myocardial (Myo) and epicardial (Epi) layers were -22.9 ± 2.7, -20.0 ± 2.4 and -17.5 ± 2.1, respectively. The GLSEndo/GLSMyo ratio was 1.1 ± 0.05, while the GLSEndo/GLSEpi ratio was 1.3 ± 0.05. The apical strain-sparing ratio was >1 in 10% of the subjects (endocardium) and 7% (mid-myocardium). The lower limits for segmental LS were as follows: for endocardial LS, -10% (basal), -12% (mid), -14% (apical); for mid-myocardial LS, -10% -10% (basal), -10% (mid), -10% (apical); and for epicardial LS, -7% (basal), -8% (mid), -8% (apical). The findings of this study provide data regarding the lower limit of normality of LS for each LV segment and suggest, for practical considerations, that an LS value below 10% should be considered abnormal in any segment. Further larger studies are warranted to confirm these findings.

Oxidative Stress and Left Ventricular Performance in Patients with Different Glycometabolic Phenotypes

The aim of the present study was to evaluate the possible correlation between oxidative stress and subclinical myocardial damage, assessed with speckle tracking echocardiography (STE), in normal glucose tolerance (NGT) patients with one-hour plasma glucose values ≥ 155 mg/dL (NGT ≥ 155), comparing them to NGT < 155 subjects, impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM) newly diagnosed patients. We enrolled 100 Caucasian patients. All subjects underwent OGTT. The serum values of oxidative stress markers (8-isoprostane and Nox-2) were assessed with an ELISA test. Echocardiographic recordings were performed using an E-95 Pro ultrasound system. We observed significant differences, among the four groups, for fasting plasma glucose (p < 0.0001), one-hour postload (p < 0.0001), and two-hour postload plasma glucose (p < 0.0001). As compared with NGT < 155, NGT ≥ 155 exhibited significantly worse insulin sensitivity and higher values of hs-CRP. No significant differences were observed between NGT ≥ 155 and IGT patients. There was a significant increase in 8-isoprostane (p < 0.0001) and Nox-2 (p < 0.0001), from the first to fourth group, indicating an increase in oxidative stress with the worsening of the metabolic status. Serum levels of 8-isoprostane and Nox-2 were significantly increased in NGT ≥ 155 compared to the NGT < 155 group, but similar to IGT. The global longitudinal strain (GLS) appeared progressively lower proceeding from the NGT < 155 to T2DM group (p < 0.0001). For similar values of left ventricular ejection fraction (LVEF), NGT ≥ 155 exhibited reduced GLS compared to NGT < 155 (p = 0.001), but similar to IGT patients. Our study demonstrated that NGT ≥ 155 subjects exhibit early functional impairment of myocardial contractile fibres, these alterations are correlated with increased oxidative stress.

Age- and sex-based normal values of layer-specific longitudinal and circumferential strain by speckle tracking echocardiography: the Copenhagen City Heart Study

AIMS

Technical advancements in 2D-speckle tracking echocardiography (2DSTE) have allowed for quantification of layer-specific global longitudinal strain (GLS) and circumferential strain (GCS) of the left ventricle (LV). The aim of this study was to establish age- and sex-based reference ranges of peak systolic layer-specific GLS and GCS and to assess normal values of regional strain.

METHODS AND RESULTS

We performed 2DSTE analysis of 1997 members of the general population from the fifth round of the Copenhagen City Heart Study, who were free of cardiovascular disease and risk factors. The mean age was 46 ± 16 years (range 21-97) and 62% were female. Mean values for peak systolic whole wall GLS (GLSWW.Sys), endomycardial (GLSEndo.Sys), and epimyocardial (GLSEpi.Sys) were 19.9 ± 2.1% (prediction interval [PI]: 15.8-24.0%), 23.5 ± 2.5% (PI: 18.6-28.4%), and 17.3 ± 1.9% (PI: 13.6-21.1%), respectively. Mean peak systolic whole wall GCS (GCSWW.Sys), was 21.6 ± 3.7% (PI: 14.3-28.9%), endomyocardial (GCSEndo.Sys) was 31.9 ± 4.7% (PI: 22.7-41.1%), and epimyocardial (GCSEpi.Sys) was 14.3 ± 3.8% (PI: 6.8-21.8%). A significant discrepancy in normal strain values between males and females was observed. Men had lower mean values and lower reference limits for all strain parameters. Furthermore, GLS and GCS changed differently with age in males and females. Finally, regional LS decreased from the apical to the basal LV region in both sexes, and regional CS varied significantly by LV segment.

CONCLUSION

In this study, we reported age- and sex-based reference ranges of layer-specific GLS and GCS. These reference ranges varied significantly with sex and age.

Layer-Specific Strain Is Preload Dependent: Comparison between Speckle-Tracking Echocardiography and Cardiac Magnetic Resonance Feature-Tracking

BACKGROUND

Speckle-tracking echocardiographic (STE) imaging and cardiac magnetic resonance feature-tracking (CMR-FT) are novel imaging techniques enabling layer-specific quantification of myocardial deformation. Conventional echocardiographic parameters are load dependent, but few studies have investigated the effects of loading conditions on STE and CMR-FT layer-specific strain and the interchangeability of the two modalities. The aim of this study was to evaluate the effects of acute preload augmentation by saline infusion on STE and CMR-FT longitudinal and circumferential layer-specific strain parameters and their intermodal agreement.

METHODS

A total of 80 subjects, including 41 control subjects (mean age, 40 ± 12 years; 49% men) and 39 patients with cardiac disease (mean age, 47 ± 15 years; 92% men) were examined using STE and CMR-FT layer-specific strain analysis before and after saline infusion (median, 2.0 L) with quantification of transmural global longitudinal strain (GLS), epicardial GLS, endocardial GLS, transmural global circumferential strain (GCS), epicardial GCS, and endocardial GCS in addition to epicardial-endocardial gradients. Bland-Altman plots and Pearson correlation coefficients were used to evaluate agreement between the two modalities across all strain parameters.

RESULTS

Acute saline infusion increased all STE and CMR-FT layer-specific strain parameters in both groups. STE and CMR-FT GLS increased by 1.4 ± 1.5% and 1.5 ± 2.0% (P < .001) in control subjects and by 0.9 ± 1.8% and 0.9 ± 1.9% (P < .001) in patients with cardiac disease. STE and CMR-FT GCS increased by 2.0 ± 2.2% and 1.8 ± 2.3% (P < .001) in control subjects and by 1.8 ± 2.3% and 1.7 ± 3.6% in patients with cardiac disease (P < .001 and P = .03). STE longitudinal strain correlated strongly with corresponding CMR-FT longitudinal strain (GLS, epicardial GLS, and endocardial GLS: r = 0.81, r = 0.82, and r = 0.81, respectively) despite poor intermodal agreement (bias ± limits of agreement, -2.84 ± 4.06%, 0.16 ± 3.68%, and 2.33 ± 3.52%, respectively) whereas GCS, epicardial GCS, and endocardial GCS correlated weakly between the two modalities (r = 0.28, r = 0.19, and r = 0.34, respectively) and displayed poor intermodal agreement (bias ± limits of agreement, -1.33 ± 6.86%, 4.43 ± 6.49%, and -9.92 ± 8.55%, respectively).

CONCLUSIONS

STE and CMR-FT longitudinal and circumferential layer-specific strain parameters are preload dependent in both control subjects and patients with cardiac disease. STE and CMR-FT longitudinal layer-specific strain parameters are strongly correlated, whereas circumferential layer-specific strain parameters are weakly correlated. STE and CMR-FT longitudinal and circumferential strain should not be used interchangeably, because of poor intermodal agreement.

Echocardiographic reference ranges for normal left ventricular layer-specific strain: results from the EACVI NORRE study

AIMS

To obtain the normal range for 2D echocardiographic (2DE) measurements of left ventricular (LV) layer-specific strain from a large group of healthy volunteers of both genders over a wide range of ages.

METHODS AND RESULTS

A total of 287 (109 men, mean age: 46 ± 14 years) healthy subjects were enrolled at 22 collaborating institutions of the EACVI Normal Reference Ranges for Echocardiography (NORRE) study. Layer-specific strain was analysed from the apical two-, three-, and four-chamber views using 2DE software. The lowest values of layer-specific strain calculated as ±1.96 standard deviations from the mean were -15.0% in men and -15.6% in women for epicardial strain, -16.8% and -17.7% for mid-myocardial strain, and -18.7% and -19.9% for endocardial strain, respectively. Basal-epicardial and mid-myocardial strain decreased with age in women (epicardial; P = 0.008, mid-myocardial; P = 0.003) and correlated with age (epicardial; r = -0.20, P = 0.007, mid-myocardial; r = -0.21, P = 0.006, endocardial; r = -0.23, P = 0.002), whereas apical-epicardial, mid-myocardial strain increased with the age in women (epicardial; P = 0.006, mid-myocardial; P = 0.03) and correlated with age (epicardial; r = 0.16, P = 0.04). End/Epi ratio at the apex was higher than at the middle and basal levels of LV in men (apex; 1.6 ± 0.2, middle; 1.2 ± 0.1, base 1.1 ± 0.1) and women (apex; 1.6 ± 0.1, middle; 1.1 ± 0.1, base 1.2 ± 0.1).

CONCLUSION

The NORRE study provides useful 2DE reference ranges for novel indices of layer-specific strain.

A new integrated approach to cardiac mechanics: reference values for normal left ventricle

The association between left ventricular (LV) myocardial deformation and hemodynamic forces is still mostly unexplored. The normative values and the effects of demographic and technical factors on hemodynamic forces are not known. The authors studied the association between LV myocardial deformation and hemodynamic forces in a large cohort of healthy volunteers. One-hundred seventy-six consecutive subjects (age range, 16-82; 51% women), with no cardiovascular risk factors or any relevant diseases, were enrolled. All subjects underwent an echo-Doppler examination. Both 2D global myocardial and endocardial longitudinal strain (GLS), circumferential strain (GCS), and the hemodynamic forces were measured with new software that enabled to calculate all these values and parameters from the three apical views. Higher LV mass index and larger LV volumes were found in males compared to females (85 ± 17 vs 74 ± 15 g/m² and 127 ± 28 vs 85 ± 18 ml, p < 0.0001 respectively) while no differences of the mean values of endocardial and myocardial GLS and of myocardial GCS were found (p = ns) and higher endocardial GCS in women (- 30.6 ± 4.2 vs - 31.8 ± 3.7; p = 0.05). LV longitudinal force, LV systolic longitudinal force and LV impulse were higher in men (16.2 ± 5.3 vs 13.2 ± 3.6; 25.1 ± 7.9 vs 19.4 ± 5.6 and 20.4 ± 7 vs 16.6 ± 5.2, p < 0.0001, respectively). A weak but statistically significant decline with age (p < 0.0001) was also found for these force parameters. This new integrated approach could differentiate normality from pathology by providing average deformation values and hemodynamic forces parameters, differentiated by age and gender.

Transmural difference in myocardial damage assessed by layer-specific strain analysis in patients with ST elevation myocardial infarction

We performed layer-specific strain analysis with speckle-tracking echocardiography to investigate the transmural difference of myocardial damage as the predicting factor for the viability of damaged myocardium in patients with ST segment elevation myocardial infarction (STEMI). We analysed patients with acute STEMI who had undergone primary percutaneous coronary intervention and echocardiography within 24 h from the intervention and 2 months after the event. Segmental strains of the left ventricular (LV) endocardium, myocardium, epicardium, and strain gradient (SG) between the endocardium and epicardium were evaluated. In 34 patients, 112 akinetic/dyskinetic and 94 hypokinetic segments were observed among 612 segments of the LV at baseline, and 65 akinetic/dyskinetic segments had viability. In our study, layer-specific strains were gradually deteriorated by their wall motion. SG was augmented in the hypokinetic segments where inhomogeneous wall motion impairment was progressed. SG in the akinetic/dyskinetic segments was different between the viable and non-viable myocardium and was maintained in viable segments. We therefore believe that significantly reduced SG is indicative of irreversible transmural damage in the acute stage of STEMI and can be suitably used as a parameter for predicting myocardial viability.

Ventricular strain analysis in patients with no structural heart disease using a vendor-independent speckle-tracking software

Background

Ventricular strain measurements vary depending on cardiac chamber (left ventricle [LV] or right ventricle [RV]), type of strain (longitudinal, circumferential, or radial), ventricular level (basal, mid, or apical), myocardial layer (endocardial or epicardial), and software used for analysis, among other demographic factors such as age and gender. Here, we present an analysis of ventricular strain taking all of these variables into account in a cohort of patients with no structural heart disease using a vendor-independent speckle-tracking software.

Methods

LV and RV full-thickness strain parameters were retrospectively measured in 102 patients (mean age 39 ± 15 years; 62% female). Within this cohort, we performed further layer-specific strain analysis in 20 subjects. Data were analyzed for global and segmental systolic strain, systolic strain rate, early diastolic strain rate, and their respective time-to-peak values.

Results

Mean LV global longitudinal, circumferential, and radial strain values for the entire cohort were − 18.4 ± 2.0%, − 22.1 ± 4.1%, and 43.9 ± 12.1% respectively, while mean RV global and free wall longitudinal strain values were − 24.2 ± 3.9% and − 26.1 ± 5.2% respectively. Women on average demonstrated higher longitudinal and circumferential strain and strain rate than men, and longer corresponding time-to-peak values. Longitudinal strain measurements were highest at the apex compared with the mid ventricle and base, and in the endocardium compared with the epicardium. Longitudinal strain was the most reproducible measure, followed closely by circumferential strain, while radial strain showed suboptimal reproducibility.

Conclusions

We present an analysis of ventricular strain in patients with no structural heart disease using a vendor-independent speckle-tracking software.

Speckle tracking echocardiography in patients with systemic lupus erythematosus: A meta-analysis

BACKGROUND

Systemic lupus erythematosus (SLE), is characterized by a systemic involvement including myocardial dysfunction. Being standard echocardiography not able at fully detecting subclinical alterations, speckle tracking echocardiography (STE) has recently emerged as a quantitative ultrasound technique to accurately estimate myocardial function.

METHODS

We conducted a systematic review with meta-analysis of studies reporting STE parameters in patients with SLE.

RESULTS

A total of 9 studies were included in the analysis. Left ventricle global longitudinal strain (GLS) was significantly lower in SLE patients than in non-SLE controls (MD: -2.331, 95% CI: -3.083, -1.580, p < 0.001). In addition, we found significant differences between SLE patients and non-SLE controls in left ventricle GLS rate (MD: -0.115, 95% CI: -0.177 to 0.063, p < 0.001), left ventricle circumferential strain(MD: -1.841, 95% CI: -3.160 to 0.521, p = 0.006) and left ventricle radial strain(MD: -11.03, 95% CI: -13.819 to 8.241, p < 0.001). Right ventricle strain was significantly lower in SLE patients than in non-SLE controls (MD: -5.814, 95% CI: -7.347, -4.281, p < 0.001). Meta-regression models showed a lower difference in left ventricle GLS between SLE cases and controls for studies with a higher prevalence of female gender and higher prevalence of hypertension.

CONCLUSIONS

SLE patients have lower STE parameters than controls, thus suggesting the presence of an impaired myocardial function involving both left and right ventricle.

Range Variability in CMR Feature Tracking Multilayer Strain across Different Stages of Heart Failure

Heart failure (HF) is associated with progressive ventricular remodeling and impaired contraction that affects distinctly various regions of the myocardium. Our study applied cardiac magnetic resonance (CMR) feature tracking (FT) to assess comparatively myocardial strain at 3 distinct levels: subendocardial (Endo-), mid (Myo-) and subepicardial (Epi-) myocardium across an extended spectrum of patients with HF. 59 patients with HF, divided into 3 subgroups as follows: preserved ejection fraction (HFpEF, N = 18), HF with mid-range ejection fraction (HFmrEF, N = 21), HF with reduced ejection fraction (HFrEF, N = 20) and a group of age- gender- matched volunteers (N = 17) were included. Using CMR FT we assessed systolic longitudinal and circumferential strain and strain-rate at Endo-, Myo- and Epi- levels. Strain values were the highest in the Endo- layer and progressively lower in the Myo- and Epi- layers respectively, this gradient was present in all the patients groups analyzed but decreased progressively in HFmrEF and further on in HFrEF groups. GLS decreased with the severity of the disease in all 3 layers: Normal > HFpEF > HFmrEF > HFrEF (Endo-: −23.0 ± 3.5 > −20.0 ± 3.3 > −16.4 ± 2.2 > −11.0 ± 3.2, p < 0.001, Myo-: −20.7 ± 2.4 > −17.5.0 ± 2.6 > −14.5 ± 2.1 > −9.6 ± 2.7, p < 0.001; Epi-: −15.7 ± 1.9 > −12.2 ± 2.1 > −10.6 ± 2.3 > −7.7 ± 2.3, p < 0.001). In contrast, GCS was not different between the Normal and HFpEF (Endo-: −34.5 ± 6.2 vs −33.9 ± 5.7, p = 0.51; Myo-: −21.9 ± 3.8 vs −21.3 ± 2.2, p = 0.39, Epi-: −11.4 ± 2.0 vs −10.9 ± 2.3, p = 0.54) but was, as well, markedly lower in the systolic heart failure groups: Normal > HFmrEF > HFrEF (Endo-: −34.5 ± 6.2 > −20.0 ± 4.2 > 12.3 ± 4.2, p < 0.001; Myo-: −21.9 ± 3.8 > −13.0 ± 3.4 > −8.0 ± 2.7. p < 0.001; Epi-: −11.4 ± 2.0 > −7.9 ± 2.3 > −4.5 ± 1.9. p < 0.001). CMR feature tracking multilayer strain assessment identifies large range differences between distinct myocardial regions. Our data emphasizes the importance of sub-endocardial myocardium for cardiac contraction and thus, its predilect role in imaging detection of functional impairment. CMR feature tracking offers a convenient, readily available, platform to evaluate myocardial contraction with excellent spatial resolution, rendering further details about discrete areas of the myocardium. Using this technique across distinct groups of patients with heart failure (HF), we demonstrate that subendocardial regions of the myocardium exhibit much higher strain values than mid-myocardium or subepicardial and are more sensitive to detect contractile impairment. We also show comparatively higher values of circumferential strain compared with longitudinal and a higher sensitivity to detect contractile impairment. A newly characterized group of patients, HF with mid-range ejection fraction (EF), shows similar traits of decompensation but has relatively higher strain values as patients with HF with reduced EF.

Echocardiography and cardiovascular magnetic resonance based evaluation of myocardial strain and relationship with late gadolinium enhancement

OBJECTIVES

We sought to: (1) determine the agreement in cardiovascular magnetic resonance (CMR) and speckle tracking echocardiography (STE) derived strain measurements, (2) compare their reproducibility, (3) determine which approach is best related to CMR late gadolinium enhancement (LGE).

BACKGROUND

While STE-derived strain is routinely used to assess left ventricular (LV) function, CMR strain measurements are not yet standardized. Strain can be measured using dedicated pulse sequences (strain-encoding, SENC), or post-processing of cine images (feature tracking, FT). It is unclear whether these measurements are interchangeable, and whether strain can be used as an alternative to LGE.

METHODS

Fifty patients underwent 2D echocardiography and 1.5 T CMR. Global longitudinal strain (GLS) was measured by STE (Epsilon), FT (NeoSoft) and SENC (Myocardial Solutions) and circumferential strain (GCS) by FT and SENC.

RESULTS

GLS showed good inter-modality agreement (r-values: 0.71-0.75), small biases (< 1%) but considerable limits of agreement (- 7 to 8%). The agreement between the CMR techniques was better for GLS than GCS (r = 0.81 vs 0.67; smaller bias). Repeated measurements showed low intra- and inter-observer variability for both GLS and GCS (intraclass correlations 0.86-0.99; coefficients of variation 3-13%). LGE was present in 22 (44%) of patients. Both SENC- and FT-derived GLS and GCS were associated with LGE, while STE-GLS was not. Irrespective of CMR technique, this association was stronger for GCS (AUC 0.77-0.78) than GLS (AUC 0.67-0.72) and STE-GLS (AUC = 0.58).

CONCLUSION

There is good inter-technique agreement in strain measurements, which were highly reproducible, irrespective of modality or analysis technique. GCS may better reflect the presence of underlying LGE than GLS.

Reproducibility and Agreement of Tissue Tracking versus Feature Tracking for Strain Measurement on Cardiac MR Images in Patients with Repaired Tetralogy of Fallot

PURPOSE

To evaluate differences in strain measurements by using tissue-tracking (TT) and feature-tracking (FT) software on cardiovascular MR images in patients with repaired tetralogy of Fallot (TOF).

MATERIALS AND METHODS

In this retrospective cross-sectional study of 25 patients with repaired TOF (median age, 33.1 years; interquartile range, 25.3-38.3 years) from 2008 through 2014, left ventricular (LV) and right ventricular (RV) global circumferential and longitudinal strain were measured from cardiac MR images by using TT and FT software. Time to process was measured from opening the study to acceptance of contours. Intra- and interobserver reproducibility were evaluated with Bland-Altman analysis, coefficient of variation, and intraclass correlation coefficient.

RESULTS

Time to process was slightly longer for TT (10.2 minutes ± 3.1 [standard deviation] vs 9.0 minutes ± 1.7, P = .04). Fewer patients required contour revision with TT than with FT. Both TT and FT measurements had similar moderate-to-strong correlations with LV and RV ejection fractions; correlation of RV longitudinal strain with RV ejection fraction did not reach significance by using either method. With the exception of LV circumferential strain, strain measurements were lower with FT relative to TT. Intra- and interobserver reproducibility were lower with FT for longitudinal strain measurements.

CONCLUSION

TT and FT have systematic differences in strain values and reproducibility, particularly for longitudinal strain. Software-specific normative data are necessary, as are studies to evaluate correlation with clinical outcomes for each modality.© RSNA, 2019.

Assessment of the left ventricular function in patients with uremia using layer-specific 2-dimensional speckle tracking echocardiography

The aim of this research is to evaluate the longitudinal and circumferential systolic function of the left ventricle with different configurations from endocardium, midmyocardium, and epicardium, respectively, in patients with uremia using layer-specific 2-dimensional speckle tracking echocardiography (2D-STE).According to the different left ventricular (LV) configurations, 119 patients with uremia were divided into 2 groups: LV normal group (LVN group, n = 63) and LV hypertrophy group (LVH group, n = 56). In all, 66 healthy volunteers were selected as controls. High-frame rate 2-dimensional images were recorded from the apical 4-chamber view, apical 2-chamber view, parasternal LV long-axis view, and mitral annulus, papillary muscle, and apical levels of the parasternal LV short-axis view during 3 consecutive cardiac cycles. The peak systolic longitudinal strain (LS) and circumferential strain (CS) were measured in the endocardium, midmyocardium, and epicardium.In the 3 groups, the endocardium had the highest LS and CS, whereas the epicardium had the lowest LS and CS; the LS and CS of each group gradually decreased from the endocardium to the epicardium in all the 3 sections; the LS and CS of the myocardial layers were kept gradient features, namely, endocardium > midmyocardium > epicardium. The LS of the endocardium in the LVN and LVH groups was significantly lower than that in the control group (P < .05). The LS of the midmyocardium and epicardium in the LVH group were significantly lower than those in the control group (P < .05). The LS of the endocardium significantly decreased in the LVH group compared with that in the LVN group (P < .05). The CS of the endocardium and midmyocardium in the LVH group significantly decreased compared with those in the control and LVN groups (P < .05). There were no significant differences in the CS between the LVN and control groups (P > .05).In patients with uremia, the longitudinal and circumferential systolic function in 3 myocardial layers of the LVH group, and the longitudinal systolic function in endocardium of the LVN group were found significantly impaired by layer-specific 2D-STE.

Left Ventricular Strain Is Abnormal in Preclinical and Overt Hypertrophic Cardiomyopathy: Cardiac MR Feature Tracking

Purpose To evaluate myocardial strain and circumferential transmural strain difference (cTSD; the difference between epicardial and endocardial circumferential strain) in a genotyped cohort with hypertrophic cardiomyopathy (HCM) and to explore correlations between cTSD and other anatomic and functional markers of disease status. Left ventricular (LV) dysfunction may indicate early disease in preclinical HCM (sarcomere mutation carriers without LV hypertrophy). Cardiac MRI feature tracking may be used to evaluate myocardial strain in carriers of HCM sarcomere mutation. Materials and Methods Participants with HCM and their family members participated in a prospective, multicenter, observational study (HCMNet). Genetic testing was performed in all participants. Study participants underwent cardiac MRI with temporal resolution at 40 msec or less. LV myocardial strain was analyzed by using feature-tracking software. Circumferential strain was measured at the epicardial and endocardial surfaces; their difference yielded the circumferential transmural strain difference (cTSD). Multivariable analysis to predict HCM status was performed by using multinomial logistic regression adjusting for age, sex, and LV parameters. Results Ninety-nine participants were evaluated (23 control participants, 34 participants with preclinical HCM [positive for sarcomere mutation and negative for LV hypertrophy], and 42 participants with overt HCM [positive for sarcomere mutation and negative for LV hypertrophy]). The average age was 25 years ± 11 and 44 participants (44%) were women. Maximal LV wall thickness was 9.5 mm ± 1.4, 9.8 mm ± 2.2, and 16.1 mm ± 5.3 in control participants, participants with preclinical HCM (P = .496 vs control participants), and participants with overt HCM (P < .001 vs control participants), respectively. cTSD for control participants, preclinical HCM, and overt HCM was 14% ± 4, 17% ± 4, and 22% ± 7, respectively (P < .01 for all comparisons). In multivariable models (controlling for septal thickness and log-transformed N-terminal brain-type natriuretic peptide), cTSD was predictive of preclinical and overt HCM disease status (P < .01). Conclusion Cardiac MRI feature tracking identifies myocardial dysfunction not only in participants with overt hypertrophic cardiomyopathy, but also in carriers of sarcomere mutation without left ventricular hypertrophy, suggesting that contractile abnormalities are present even when left ventricular wall thickness is normal. © RSNA, 2018 Online supplemental material is available for this article.

Layer-specific myocardial function in asymptomatic cats with obstructive hypertrophic cardiomyopathy assessed using 2-dimensional speckle-tracking echocardiography

Background

Hypertrophic cardiomyopathy (HCM), a primary disorder of the myocardium, is the most common cardiac disease in cats. However, determination of layer‐specific myocardial function with 2D speckle‐tracking echocardiography in cats with asymptomatic HCM has not yet been reported.

Objectives

To quantitatively measure layer‐specific myocardial function of asymptomatic cats with HCM.

Animals

Ten client‐owned, asymptomatic cats with obstructive HCM and 13 healthy cats.

Methods

A retrospective, case‐control study. Cats underwent assessment of layer‐specific myocardial function (whole, endocardial, and epicardial) in the longitudinal and circumferential directions by using 2D speckle‐tracking echocardiography.

Results

Longitudinal strains were significantly lower in cats with HCM than controls in the whole (−15.5% vs −19.1%), endocardial (−18.3% vs −21.8%), and epicardial (−13.1% vs −16.8%) layers. Circumferential strains in whole and epicardial layers also were significantly lower in cats with HCM as compared with controls (−15.0% vs −20.2% and − 4.4% vs −9.4%, respectively). However, no significant difference was found between cats with HCM and controls in the global circumferential strain in the endocardial layer (−31.2% vs −34.2%). The circumferential endocardial‐to‐epicardial strain ratio was significantly higher in cats with HCM than in controls (6.1 vs 3.5).

Conclusions and Clinical Importance

Layer‐specific myocardial function assessed by 2D speckle‐tracking echocardiography differed in asymptomatic cats with obstructive HCM compared to controls despite their apparently normal systolic function, as determined by conventional echocardiography. The maintained endocardial circumferential strain and higher circumferential endocardial‐to‐epicardial strain ratio may reflect compensation for occult systolic dysfunction in cats with obstructive HCM.

Does Masked Hypertension Cause Early Left Ventricular Impairment in Youth?

Objectives: Masked hypertension (MH) is not uncommon in the youth and may increase risks of long-term cardiovascular impairment. However, little is known about the subclinical heart damage in this group of patients. Currently, 3-layer speckle tracking imaging based on two-dimensional echocardiography is feasible to detect the early signs of myocardial damage. We therefore aimed to investigate whether subtle changes of cardiac function occurred in the young MH patients by using advanced quantification with layer-specific speckle tracking. Methods: A total of 40 adolescents with MH (age 18 ± 3 years, 73% males) and 40 age-, gender-, race-, and height-matched normotensive volunteers were enrolled in our study. MH was defined as one or more of the ambulatory blood pressure (BP) parameters (24-h, daytime and night-time average BPs) higher than ≥ 95th percentile for gender and height according to the local reference. Both comprehensive two-dimensional echocardiography with layer-specific strain analysis and 24-h ambulatory BP monitoring were performed. Longitudinal strain and circumferential strain in endocardial, mid-myocardial, and epicardial layers were determined accordingly with the dedicated software (EchoPAC software version 201, GE Healthcare, Horten, Norway). Results: Compared with normotensive controls, youths with MH had higher ambulatory pulse rate and left ventricular mass index, and were more obese. Interestingly, similar ventricular volumes and ejection fraction were observed in the study groups, but further analysis with layer-specific strains revealed that endocardial and mid-myocardial longitudinal and circumferential mechanical function were decreased in the young MH subjects when compared to normotensive individuals (all p < 0.05). However, there were no difference regarding radial strain and apical rotation derived from traditional speckle tracking analysis. Conclusion: Subclinical change of LV mechanic function assessed by layer-specific speckle tracking is present in youth with MH despite considered as normal with conventional ways.Thus, MH in youth should be monitored closely instead of labeling as an entirely benign entity.

Reference Ranges and Regional Patterns of Left Ventricular Strain and Strain Rate Using Two-Dimensional Speckle-Tracking Echocardiography in a Healthy Middle-Aged Black and White Population: The CARDIA Study

BACKGROUND

Strain and strain rate are sensitive markers of left ventricular (LV) myocardial function. The aim of this study was to assess reference ranges and regional patterns of LV strain and strain rate using two-dimensional speckle-tracking echocardiography in a large population of black and white subjects.

METHODS

This study involved a retrospective review of prospectively collected images in 557 participants in the Coronary Artery Risk Development in Young Adults study who remained healthy at the year 25 examination. LV deformation parameters were measured in apical four-chamber, apical two-chamber, and parasternal short-axis views in 509, 391, and 521 subjects, respectively.

RESULTS

Patients' mean age was 49.6 ± 3.6 years, 61.6% were women, and 69.5% were white. White women showed the highest LV systolic and diastolic deformation values, reflected by a more negative reference range for apical four-chamber longitudinal strain (-16.4%; 95% prediction interval [PI], -20.8% to -12.0%) and a higher positive reference range for early diastolic strain rate (0.93 1/sec; 95% PI, 0.41 to 1.46 1/sec), respectively. The lowest LV systolic and diastolic deformation values were found in black men, with apical four-chamber longitudinal strain (14.7%; 95% PI, -19.1% to -10.3%) and early diastolic strain rate (0.79 1/sec; 95% PI, 0.42 to 1.16 1/sec). Absolute strain increased from the epicardium toward the endocardium. A base-to-apex gradient of longitudinal strain toward the apex was exhibited in inferior and inferoseptal regions and, in contrast, in the opposite direction in anterior and anterolateral walls. Sex had the strongest influence on LV deformation variability.

CONCLUSIONS

Strain and strain rate reference values were sex and race related. White women showed the highest reference ranges for LV deformation, while the lowest values were found in black men. Significant layer- and level-specific patterns in regional LV deformation were identified.

Normal range of myocardial layer-specific strain using two-dimensional speckle tracking echocardiography

Background

Newer 2D strain software has a potential to assess layer-specific strain. However, normal reference values for layer-specific strain have not been established. We aimed to establish the normal ranges of layer-specific longitudinal and circumferential strain (endocardial global longitudinal strain (GLS), transmural GLS, epicardial GLS, endocardial global circumferential strain (GCS), transmural GCS, and epicardial GCS).

Methods and results

We retrospectively analyzed longitudinal and circumferential strain parameters in 235 healthy subjects, with use of layer-specific 2D speckle tracking software (GE). The endocardial strain/epicardial strain (Endo/Epi) ratio was also measured to assess the strain gradient across the myocardium. The endocardial, transmural, and epicardial GLS values and the Endo/Epi ratio in the normal subjects were -23.1±2.3, -20.0±2.0, -17.6±1.9, and 1.31±0.07, respectively. The corresponding values of GCS were -28.5±3.0, -20.8±2.3, -15.3±2.0, and 1.88±0.17, respectively. The layer-specific global strain parameters exhibited no age dependency but did exhibit gender dependency except for endocardial GCS. A subgroup analysis revealed that basal and middle levels of endocardial LS was decreased in the middle and elderly aged group. However, apical endocardial LS was preserved even in the elderly subjects.

Conclusions

We proposed normal reference values for layer-specific strain based on both age and gender. This detailed strain analysis provides layer-oriented information with the potential to characterize abnormal findings in various cardiovascular diseases.

Distribution pattern of left-ventricular myocardial strain analyzed by a cine MRI based deformation registration algorithm in healthy Chinese volunteers

The cine magnetic resonance imaging based technique feature tracking-cardiac magnetic resonance (FT-CMR) is emerging as a novel, simple and robust method to evaluate myocardial strain. We investigated the distribution characteristics of left-ventricular myocardial strain using a novel cine MRI based deformation registration algorithm (DRA) in a cohort of healthy Chinese subjects. A total of 130 healthy Chinese subjects were enrolled. Three components of orthogonal strain (radial, circumferential, longitudinal) of the left ventricle were analyzed using DRA on steady-state free precession cine sequence images. A distinct transmural circumferential strain gradient was observed in the left ventricle that showed universal increment from the epicardial to endocardial myocardial wall (epiwall: -15.4 ± 1.9%; midwall: -18.8 ± 2.0%; endowall: -22.3 ± 2.3%, P < 0.001). Longitudinal strain showed a similar trend from epicardial to endocardial layers (epiwall: -16.0 ± 2.9%; midwall: -15.6 ± 2.7%; endowall: -14.8 ± 2.4%, P < 0.001), but radial strain had a very heterogeneous distribution and variation. In the longitudinal direction from the base to the apex of the left ventricle, there was a trend of decreasing peak systolic longitudinal strain (basal: -23.3 ± 4.6%; mid: -13.7 ± 7.3%; apical: -13.2 ± 5.5%; P < 0.001). In conclusion, there are distinct distribution patterns of circumferential and longitudinal strain within the left ventricle in healthy Chinese subjects. These distribution patterns of strain may provide unique profiles for further study in different types of myocardial disease.

Right ventricular strain as predictor of pulmonary complications in patients with femur fracture

Background:

Following femur fracture, medullary fat enters the systemic circulation and altered pulmonary haemodynamics may contribute to pulmonary complications. This study evaluated the association between right ventricular (RV) function and pulmonary complications in patients with femur fracture.

Methods:

Patients with a femur fracture who had undergone pre-operative echocardiography that included RV peak global longitudinal strain (RV GLS) were evaluated retrospectively between March 2015 and February 2016. Pulmonary complications were defined as the development of pneumonia or pulmonary thromboembolism during the first postoperative month.

Results:

Among 78 patients, pulmonary complications developed in eight (10.3%). The RV GLS value of all patients was lower than the normal range. In addition, the RV GLS value of patients with pulmonary complications was significantly lower than that of patients without pulmonary complications. Multivariate regression analyses found that worse RV GLS values independently predicted pulmonary complications [odds ratio (OR) 2.09, 95% confidence interval (CI) 1.047–4.151, p = 0.037]. Receiver operating characteristic curve analysis found that a RV GLS value of –14.85% was the best cut-off value to predict pulmonary complications; sensitivity: 75.0%; specificity: 62.9%. Moreover, patients with RV GLS values > –14.85% had significantly lower pulmonary complication-free survival.

Conclusions:

In patients with femur fracture, RV GLS values could help predict pulmonary complications. Therefore, patients with RV GLS values > –14.85 should be monitored closely before and after surgery for femur fracture.

Multilayer longitudinal strain at rest may help to predict significant stenosis of the left anterior descending coronary artery in patients with suspected non-ST-elevation acute coronary syndrome

Two-dimensional speckle tracking echocardiography (2D-STE) multilayer analysis of myocardial deformation is a non-invasive method that enables discrimination of transmural differences owing to myocardial ischemia or necrosis. We wished to ascertain if multilayer longitudinal strains at rest are associated with significant (≥70 %) stenosis of the left anterior descending coronary artery (LAD) in patients with suspected non-ST-elevation acute coronary syndrome (NSTE-ACS). Our cohort comprised 113 consecutive patients with suspected NSTE-ACS and preserved ejection fraction (EF). Using coronary angiography, we diagnosed 63 patients with significant stenosis of the LAD and 50 patients without significant coronary artery disease. Echocardiography was done ≤48 h before angiography. Multilayer longitudinal strains were assessed from the endocardium, mid-myocardium and epicardium by 2D-STE. Regional longitudinal strain in LAD territory (RLS_LAD) was calculated as the mean peak systolic longitudinal strain of segments subtended by the LAD for all myocardial layers. Significant differences were observed in all strain parameters between the two groups. RLS_LAD and global longitudinal strain in the endocardium showed higher accuracy than that in the mid-myocardium and epicardium, wall motion score index (WMSI), WMSI in LAD territory, and EF for detection of significant LAD stenosis (all P < 0.05), with areas under the receiver operating characteristic curve of 0.87 and 0.91, respectively. An endocardial RLS_LAD cutoff of -23.52 % showed optimal sensitivity and specificity (88.9/80.0 %). In patients with suspected NSTE-ACS, multilayer longitudinal strain analysis at rest might enable prediction of significant LAD stenosis, and could help to identify patients requiring reperfusion.

Coupling of ventricular action potential duration and local strain patterns during reverse remodeling in responders and nonresponders to cardiac resynchronization therapy

BACKGROUND

The high risk of ventricular arrhythmias in patients with heart failure remains despite the benefit of cardiac resynchronization therapy (CRT). An electromechanical interaction between regional myocardial strain patterns and the electrophysiological substrate is thought to be important.

OBJECTIVE

We investigated the in vivo relation between left ventricular activation recovery interval (ARI), as a surrogate measure of action potential duration (APD), and local myocardial strain patterns in responders and nonresponders to CRT.

METHODS

ARIs were recorded from the left ventricular epicardium in 20 patients with CRT 6 weeks and 6 months post implantation. Two-dimensional speckle tracking echocardiography was performed at the same time to assess myocardial strains. Patients with ≥15% reduction in end-systolic volume at 6 months were classified as responders.

RESULTS

ARI decreased in responders (263 ± 46 ms vs 246 ± 47 ms, P < .01) and increased in nonresponders (235 ± 23 ms vs 261 ± 20 ms; P < .01). Time-to-peak radial, circumferential, and longitudinal strains increased in responders (41 ± 27, 35 ± 25, 56 ± 37 ms; P < .01) and decreased in nonresponders (-58 ± 26, -47 ± 26, -64 ± 27 ms; P < .01). There was a nonlinear correlation between changes in time-to-peak strain and ARIs (Spearman correlation coefficient r ≥ 0.70; P < .01). Baseline QRS duration >145 ms and QRS duration shortening with biventricular pacing were associated with ARI shortening following CRT.

CONCLUSION

Changes in ventricular wall mechanics predict local APD lengthening or shortening during CRT. Nonresponders have a worsening of myocardial strain and local APD. Baseline QRS duration >145 ms and QRS duration shortening with biventricular pacing identified patients who exhibited improvement in APD.

Different responses of the myocardial contractility by layer following acute pressure unloading in severe aortic stenosis patients

The present study evaluated change in left ventricle (LV) biomechanics, layer-by-layer, following acute pressure unloading in patients with severe aortic stenosis (AS). In twenty-eight consecutive patients with severe AS who underwent transcatheter aortic valve replacement (TAVR), LV peak global longitudinal and circumferential strains of the endo-, midmyo- and epicardium were evaluated using multilayer speckle tracking echocardiography before, 1 week after, and 1 month after TAVR. Longitudinal and circumferential strains were significantly highest in the endocardium and lowest in the epicardium at baseline. At 1 month following TAVR, longitudinal strain significantly improved in all layers compared with the baseline [endocardium (%) -16.7 ± 3.8 vs. -18.6 ± 3.3, P = 0.01; mid-myocardium -14.4 ± 3.2 vs. -16.2 ± 3.5, P < 0.01; epicardium -12.4 ± 2.8 vs. -13.6 ± 2.6, P = 0.01], whereas LV ejection fraction and circumferential strain remained unchanged. Importantly, only those with LV hypertrophy demonstrated improved longitudinal strain [endocardium (%) -15.7 ± 3.0 vs. -18.7 ± 2.9, P < 0.01; mid-myocardium -13.6 ± 2.7 vs. -16.0 ± 2.5, P < 0.01; epicardium -11.8 ± 2.4 vs. -13.7 ± 2.3, P < 0.01]. The improvement in longitudinal strain was more prominent in the endocardium, which was evident even at an early time point (1 week) after TAVR. Longitudinal strain significantly improved in all three layers following acute pressure unloading, the most prominent of which was observed in the endocardium. Evaluation of multilayer strain may provide new insights into the LV mechanics in the future.

Global longitudinal strain and global circumferential strain by speckle-tracking echocardiography and feature-tracking cardiac magnetic resonance imaging: comparison with left ventricular ejection fraction

BACKGROUND

Left ventricular (LV) ejection fraction (EF) is a routine clinical standard to assess cardiac function. Global longitudinal strain (GLS) and global circumferential strain (GCS) have emerged as important LV functional measures. The objective of this study was to determine the relationships of GLS and GCS by speckle-tracking echocardiography and featuring-tracking cardiac magnetic resonance (CMR) to CMR EF as a standard of reference in the same patients.

METHODS

A total of 73 consecutive patients aged 55 ± 15 years clinically referred for both CMR and echocardiography (EF range, 8%-78%) were studied. Routine steady-state free precession CMR images were prospectively analyzed offline using feature-tracking software for LV GLS, GCS, volumes, and EF. GLS was averaged from three standard longitudinal views and GCS from the mid-LV short-axis plane. Echocardiographic speckle-tracking was used from the similar imaging planes for GLS, GCS, LV volumes, and EF.

RESULTS

Feature-tracking CMR strain was closely correlated with speckle-tracking strain in the same patients: GLS, r = -0.87; GCS, r = -0.92 (P < .0001). End-diastolic and end-systolic volumes and EF by feature-tracking CMR were significantly correlated with standard manual tracing of multiple CMR short-axis images (r = 0.97, r = 0.98, and r = 0.97, P < .0001 for all). GLS and GCS by echocardiography and CMR feature-tracking were closely correlated with standard CMR EF: r = -0.85 and r = -0.95, respectively (P < .001). Global strain measures (in absolute values) were correlated with EF using the formula EF = 3(GLS) + 8% or EF = 2.5(GCS) + 8%.

CONCLUSIONS

GLS and GCS by feature-tracking CMR analysis was a rapid means to obtain myocardial strain similar to speckle-tracking echocardiography. GLS and GCS were closely correlated with CMR EF in this patient series and may play a role in the clinical assessment of LV function.

Feasibility and correlation of standard 2D speckle tracking echocardiography and automated function imaging derived parameters of left ventricular function during dobutamine stress test

Speckle tracking echocardiography (STE) is a method of quantitative assessment of myocardial function complementary to ejection fraction and visual evaluation. Standard STE analysis, demands manual tracing of the myocardium whereas automated function imaging (AFI) offers more convenient (based on selection of three points) assessment of longitudinal strain. Nevertheless, feasibility and correlation between both methods were not thoroughly examined, especially during tachycardia at peak stage of dobutamine stress echocardiography (DSE). We performed DSE in 238 patients (pts) with recording of apical views during baseline (0) and peak (1) DSE and analyzed them by STE and AFI. According to angiography, 127/238 pts had significant (≥70%) lesions in coronary arteries. We assessed correlations between STE and AFI derived peak systolic longitudinal strain values for global and regional parameters, feasibility, time of analysis and interobserver agreement. Global systolic longitudinal strain measured during baseline and peak stage of DSE by AFI showed very good correlation with standard STE parameters, with correlation coefficients r = 0.90 and r = 0.86 respectively (p < 0.0001). For regional parameters correlation coefficients ranged from 0.83 to 0.85 for baseline and from 0.70 to 0.79 for peak DSE. Both methods provided good and similar feasibility with only 1% segments excluded from analysis at peak stage of DSE with shorter time and lower coefficient of variance offered by AFI. Global and regional longitudinal strain achieved by faster and less operator-dependent AFI method correlate well with standard more time-consuming STE analysis during baseline and peak stage of DSE.