Two-dimensional Strain Rate Research Articles

Two-dimensional strain rate imaging study using a polarization camera and birefringent aqueous cellulose nanocrystal suspensions

The birefringence response of aqueous cellulose nanocrystal (CNC) suspensions in a two-dimensional laminar flow is measured and studied. The suspensions have CNC concentrations of 1.0 wt% (weight percentage) and 1.2 wt%. Cellulose nanocrystals are optically anisotropic rod-like particles that align when subjected to local velocity gradients, whereas at rest, they remain randomly orientated by Brownian motion. The alignment causes birefringence, a phenomenon also known as flow-induced birefringence. We study the flow through an additively manufactured flow channel and measure the amount of birefringence as well as the position of the refractive index axes by using polarizers and a polarization camera. With the help of reference data published in a previous study (Lane, Rode, et al., 2022a), strain rates are derived from the birefringence measurements and compared with numerical simulations. Two flow situations are studied, a plane Poiseuille flow and the flow around a cosine-shaped constriction. The experimentally derived shear rates for the plane Poiseuille flow are consistent with theoretical and computational results. The derived strain rates for the flow around the cosine-shaped constriction show an unexpected asymmetric profile, with the strain rates in the contraction zone being larger than in the expansion zone. The averaged orientation of the CNCs in the flow is linked to the position of the refractive index axes. In the contraction zone, the CNCs tend to align parallel to the flow, whereas in the expansion zone, the CNCs tend to align perpendicular to the flow. The results of this study are discussed in the context of previous, similar studies. The asymmetric strain rate profile around the cosine-shaped constriction is thought to originate from history effects, and the alignment of the CNCs is influenced by extensional rates.

Influence of hypertension on systolic and diastolic left ventricular function including segmental strain and strain rate.

Left ventricular (LV) systolic and diastolic functions are important cardiovascular risk predictors in patients with hypertension. However, data on segmental, layer-specific strain, and diastolic strain rates in these patients are limited. The aim of this study was to investigate segmental two-dimensional strain rate imaging (SRI)-derived parameters to characterize LV systolic and diastolic function in hypertensive individuals compared with that in normotensive individuals. The study sample comprised 1194 participants from the population-based Know Your Heart study in Arkhangelsk and Novosibirsk, Russia, and 1013 individuals from the Seventh Tromsø Study in Norway. The study population was divided into four subgroups: (A) healthy individuals with normal blood pressure (BP), (B) individuals on antihypertensive medication with normal BP, (C) individuals with systolic BP 140-159mmHg and/or diastolic BP>90mm HG, and (D) individuals with systolic BP ≥160mmHg. In addition to conventional echocardiographic parameters, global and segmental layer-specific strains and strain rates in early diastole and atrial contraction (SR E, SR A) were extracted. The strain and SR (S/SR) analysis included only segments without strain curve artifacts. With increasing BP, the systolic and diastolic global and segmental S/SR gradually decreased. SR E, a marker of impaired relaxation, showed the most distinctive differences between the groups. In normotensive controls and the three hypertension groups, all segmental parameters displayed apico-basal gradients, with the lowest S/SR in the basal septal and highest in apical segments. Only SR A did not differ between the segmental groups but increased gradually with increasing BP. End-systolic strain showed incremental epi-towards endocardial gradients, irrespective of the study group. Arterial hypertension reduces global and segmental systolic and diastolic left ventricular S/SR parameters. Impaired relaxation determined by SR E is the dominant factor of diastolic dysfunction, whereas end-diastolic compliance (by SR A) does not seem to be influenced by different degrees of hypertension. Segmental strain, SR E and SR A provide new insights into the LV cardio mechanics in hypertensive hearts.

Reduced left atrial contractile strain with speckle tracking analysis predicts abnormal plasma NTproBNP in an asymptomatic community population

BackgroundThe left atrium (LA) is closely related to left ventricular diastolic function. Two-dimensional speckle tracking strain and strain rate (SR) imaging has been applied in the study of LA function. We intended to explore the relationship between global LA deformation parameters and plasma NTproBNP levels in asymptomatic community residents with normal ejection fraction and normal LA volume.MethodsA cross-sectional sample of Beijing residents underwent comprehensive Doppler echocardiography and medical record review in 2009. Global LA longitudinal strain and SR indexes were obtained in the apical four-chamber view. LA stiffness index (LASI) was calculated as the ratio of early diastolic velocity of transmitral flow/early diastolic mitral annular motion velocity (E/E') to LA reservoir strain.ResultsA total of 620 individuals (mean age = 65.8 years, left ventricular ejection fraction = 70.8%, LA volume index = 17.9 ml/m2) were investigated in our study. 117 individuals had increased plasma NTproBNP (≥ 125 pg/ml). LA reservoir and contractile function by LA strain and SR indexes were significantly reduced in the abnormal NTproBNP group compared with the normal NTproBNP group. Multiple regression analysis indicated that LA contractile strain was a negative predictor of plasma NTproBNP in addition to indexed LA volume and E/E'. LASI was higher in the abnormal NTproBNP group and was significantly correlated with NTproBNP (r = 0.342, P < 0.001). The area under ROC analysis for LASI in predicting elevated plasma NTproBNP was 0.690, similar with LA contractile strain, E/E’ and LAVI. The cut-off value of LASI was 0.612.ConclusionsLA reservoir and contractile functions demonstrated by LA strain and SR were significantly impaired in the community-based population with increased plasma NTproBNP levels. LA contractile strain adds incremental information in predicting abnormal NTproBNP levels. As a single index, LASI showed similar diagnostic value with LAVI and E/E’ in predicting abnormal NTproBNP.

CRT-300.09 Value of Left Ventricular 2D Speckle-Tracking Parameters in Predicting the TIMI Flow Grade of the Coronary Arteries in Patients With Acute Myocardial Infarction

The achievement of TIMI grade 3 flow after STEMI is associated with greater myocardial salvage. Two-dimensional (2D) strain and strain rate analyses are novel techniques to assess myocardial deformation. This is a prospective study from September 2016 to April 2019. 80 patients with acute MI were

Tissue Doppler imaging of the atrial lateral wall: Correlation with atrial strain rate and parameters of diastolic function

To evaluate the velocity profile of the lateral wall of the left atrium (LA) using pulsed-wave color tissue Doppler imaging (TDI) on line and its correlation with two-dimensional strain rate imaging (SRI) by speckle tracking, of equal segments and phases, and other parameters of diastolic function in a population of individuals without known cardiovascular disease. A total of 91 adults aged 18-74years, without cardiovascular history, hypertension, diabetes, dyslipidemia or obesity, were evaluated. A Doppler echocardiogram was performed. The lateral wall of the LA was divided subjectively into three portions, the atrial roof was excluded; the peak velocities of the basal and midportions, and their average, were measured with pulsed-wave TDI on line and SRI. Using both techniques, a first positive wave (S'la and SRS-reservoir phase) and two negative waves (E'la and SRE-conduit phase-and A'la and SRA-atrial systole-respectively) were obtained. E'la/A'la ratio and SRE/SRA ratio were analyzed. The median age was 42years, and 54.9% of the subjects were female. S'la presented moderate correlation with S' lateralmitral annulus. Both E'la and the E'la/A'la relationships showed moderate to good correlation with various diastolic dysfunction parameters evaluatedand SRI. A'la did not present a statistically significant correlation with any of the variables evaluated. Evaluation of the lateral wall of the LA by pulsed-wave color TDI on line is feasible in the vast majority of patients. In the conduit phase, E'la and the E'la/A'la relationship showed correlation with the parameters that evaluate diastolic function and SRI.

Crustal Deformation Prior to the 2017 Jiuzhaigou, Northeastern Tibetan Plateau (China), Ms 7.0 Earthquake Derived from GPS Observations

The 2017 Jiuzhaigou Ms 7.0 earthquake occurred on the northeastern margin of the Tibetan Plateau, with no noticeable rupture surface recognized. We characterized the pre-seismic deformation of the earthquake from GPS (Global Positioning System) data at eight continuous and 73 campaign sites acquired over the 2009–2017 period. With respect to the Eurasian plate, the velocity field showed a noticeable decrease, from west of the epicenter of the Jiuzhaigou earthquake to the western edge of the Longmenshan fault, in the southeast direction. The total northwest west–southeast east shortening rate in the vicinity of the epicentral area was in the range of 1.5 mm/y to 3.1 mm/y. With a GPS velocity transect across the Huya fault (HYF), where the epicenter was located, we estimated the activity of the HYF, showing a dominant left-lateral slip rate of 3.3 ± 0.2 mm/y. We calculated strain rates using a spherical wavelet-based multiscale approach that solved for the surface GPS velocity according to multiscale wavelet basis functions while accounting for spatially variable spacing of observations. Multiscale components of the two-dimensional strain rate tensor showed a complex crustal deformation pattern. Our estimates of strain rate components at the scale of seven and eight revealed extensional strain rate on the northern extension of the HYF. The Jiuzhaigou earthquake occurred at the buffer zone between extensional and compressional deformation, and with significant maximum shear rates being 100–140 nanostrain/y. In addition, a maximum shear strain rate of 60–120 nanostrain/y appeared around the epicenter of the 2013 Ms 6.6 Minxian–Zhangxian earthquake. These findings imply that inherent multiscale strain rates could be separated to identify strain accumulation related to medium- and large-sized earthquakes.

A0524 Differentially Expressed Genes in Accumulated Epicardial Adipose Tissue Linked to Early Impaired Systolic Cardiac Deformation Ability in a Rat Model of Metabolic Syndrome

Objectives: This study aimed to detect early impairment of systolic cardiac function by two-dimensional spackle-tracking strain and strain rate analysis and it's link to epicardial adipose tissue (EAT) in a rat model of metabolic syndrome (MetS). Methods: Sixteen male six-week old SD rats were randomly divided into MetS and control groups. MetS model rats were injected with STZ (15 mg/kg) and fed with high-fat, high-salt diet and water containing 0.02% L-NAME and 10% glucose. All the rats were fed for six weeks. Plasma levels of glucose, insulin and lipids were measured. OGTT and blood pressure measurement were conducted. LVEF was calculated with M-mode echocardiography. Systolic strain and strain rate were analyzed with B-mode echocardiography. Differentially expressed genes in EAT was quantified by genome-wide expression profiling microarray. Results: MetS model rats had higher body weight, blood pressure, plasma glucose and lipids levels (P < 0.05). LVEF, endocardial systolic radial and circumferential strain and strain rate of left ventricle in MetS rats were not different from the controls (P > 0.05). Epicardial systolic radial strain and strain rate in MetS rats were also not different from the controls (P > 0.05). However, epicardial systolic circumferential strain and strain rate in MetS rats were less than the controls (P < 0.05). EAT mass related to impaired epicardial deformation ability negatively (P < 0.01). There were thirty-three differentially-expressed genes in hypertrophic cardiomyo pathway, cardiac muscle contraction pathway, adipo-cytokine signaling pathway or related to heart contraction and lipid storage in EAT in MetS rats. Conclusion: Early impairment of systolic cardiac deformation ability in MetS was possibly myocardial layer-specific. Differentially-expressed genes in EAT possibly played some effects on it.

Effects of Spinal Anaesthesia on Left Ventricular Function: An Observational Study using Two-Dimensional Strain Echocardiography.

Hypotension frequently occurs during spinal anaesthesia (SA), especially in the elderly. This side effect could have a cardiac component per se (myocardial contractility impairment). Two-dimensional (2D) strain and strain rate imaging are new echocardiographic methods allowing an accurate assessment of myocardial function by quantifying myocardial deformation. Allowing quantification of minor myocardial dysfunction not detectable by standard echocardiography, strain imaging could bring new perspective on the cardiac effect of SA. Our objective was to evaluate the effects of SA on left ventricular function assessed by 2D strain echocardiography. In this prospective observational study, we enrolled 20 patients older than 60 years, who underwent elective lower-limb surgery under SA. Myocardial strain imaging were collected before and 20 minutes after SA (injection of 10 mg of isobaric bupivacaine with 5 μg of sufentanil). We observed an increase in global longitudinal reconnoitering (Δ-0.2±0.3% s-1; p<0.005), whereas left ventricular ejection fraction was not modified by SA. This slight increase in myocardial contractility could be an adaptive mechanism to compensate the preload decrease and limit the blood pressure drop.

Contemporary Crustal Deformation Within the Pamir Plateau Constrained by Geodetic Observations and Focal Mechanism Solutions

We used an updated data set of 192 GPS-derived surface velocities and 393 earthquake focal mechanisms (Mw > 3.0, hypocenter depths < 30 km) to evaluate the spatial variations in the surface strain rate and crustal stress regime throughout the Pamir Plateau and its surrounding regions. The strain rate field was estimated using the spline in tension approach that solves for the surface velocity in a rectangular grid and the stress field was predicted from focal mechanism solutions using the damped regional-scale stress inversion (DRSSI) method of Hardebeck and Michael (Journal of Geophysical Research, https://doi.org/10.1029/2005jb004144 , 2006). The results show that the crustal stress field around the Pamir Plateau is predominantly characterized by NNW–SSE compression and E–W extension, which is consistent with the principal orientations of the two-dimensional surface strain rate tensor. This agreement supports the notion that the Pamir and southwestern Tien Shan are uniformly strained blocks. In particular, the fan-shaped rotational pattern between $${\text{Shmax}}$$ and the strain rate from the western Pamir to the Tajik Basin shows that the counterclockwise rotation of the $${\text{Shmax}}$$ orientation is associated with vertical deformation, which is consistent with the idea of Schurr et al. (Tectonics 33(8):2014TC003576, 2014) concerning the gravitational collapse and westward extrusion of the crust in the western Pamir. We propose that such a stress–strain pattern, dominated by NNW–ESE oriented compression and E–W trending extension, originated from a combination of the northward push of the Indian continent and the southward subduction of the Tien Shan.

Cardiac function in paediatric patients with congenital adrenal hyperplasia due to 21 hydroxylase deficiency.

Hyperandrogenism and exogenous glucocorticoid excess may cause unfavourable changes in the cardiovascular risk profile of patients with congenital adrenal hyperplasia (CAH). To evaluate the cardiac function in paediatric patients with CAH. Twenty-seven paediatric patients with CAH, aged 8-16years, were evaluated by physical examination, electrocardiogram (ECG), conventional echocardiography, tissue Doppler imaging and two-dimensional (2D) myocardial strain (rate) imaging. Results were compared to 27 age- and gender- matched healthy controls. No signs of left ventricular hypertrophy or dilatation were detected on echocardiography. ECG revealed a high prevalence (25.9%) of incomplete right bundle branch block. Left ventricular posterior wall thickness in diastole (LVPWd) was significantly lower in patients with CAH compared to controls (5.55 vs 6.53mm; P=.009). The LVPWd Z-score was significantly lower in patients with CAH yet within the normal range (-1.12 vs -0.35; P=.002). Isovolumetric relaxation time was significantly lower in patients with CAH (49 vs 62ms; P=.003). Global longitudinal, radial and circumferential strain was not significantly different compared to controls. Global radial strain rate was significantly higher compared to healthy controls (2.58 vs 2.06 1/s; P=.046). Global longitudinal strain was negatively correlated with 24-hour blood pressure parameters. Cardiac evaluation of paediatric patients with CAH showed no signs of left ventricular hypertrophy or ventricular dilatation. LVPWd was lower in patients with CAH than in controls but within the normal range. A shorter isovolumetric relaxation time in patients with CAH may be a sign of mild left ventricular diastolic dysfunction.

Evaluation of two-dimensional strain rate imaging on left ventricular longaxis systolic function in patients with slow coronary flow

Objective: To evaluate the value of two-dimensional strain rate imaging (STE) in detecting the alteration of regionally left ventricular long-axis systolic function in patients with slow coronary flow (SCF). Methods: 24 patients who were with SCF but without significant coronary artery stenosis in LAD were included in left anterior descending artery (LAD) group, and 15 patients with slow flow in right coronary artery (RCA) were included in RCA group, and 20 patients who were without significant coronary stenosis or abnormal corrected thrombolysis in myocardial infarction frame count (CTFC) were included in control group. CTFC was carried on 3 groups. Peak systolic strain rate (PSRs) were measured at basal, middle and apical segments in left ventricular walls, including the septal, lateral, inferior and anterior. Results: CTFC of left anterior descending coronary artery blood flow (39.88 ± 7.48) was significantly higher in LAD group than control group (19.84 ± 5.91, P<0.01). CTFC of right coronary artery blood flow (23.78 ± 8.15) was significantly higher in RCA group than control group (21.55 ± 8.12, P<0.01). PSRs of anterior wall in LAD group and interior wall in RCA group were significantly lower than that in control group (P<0.01). Linear regression showed that the CTFC of left anterior descending artery was negatively correlated with the PSRs of anterior wall (r=-0.55, P<0.01), as well as the CTFC of right coronary artery and the PSRs of interior wall in RCA group (-0.86, P<0.01). Conclusions: STE can evaluate the regional left ventricular long-axis systolic function in the patients with SCF.

A continuum model of present-day crustal deformation in the Pamir-Tien Shan region constrained by GPS data

We present a new model of crustal deformation in the Pamir-Tien Shan region. There are two different ways of assessing the deformation: block and continuum modeling. In this study we adopt a continuum modeling approach, which is based on computation of the two-dimensional strain rate tensor field of the Earth’s crust. This approach allows independent computation of the deformation at any point of the computation grid by solving an over-constrained system of linear algebraic equations based on the linear term of the Taylor series expansion of the point velocity function about its radius-vector. We propose a detailed description of this method including a significance criterion introduced by the author for estimating the reliability of modeling results. We discuss the parameters of this deformation model for the Pamir-Tien Shan region, computed from the GPS velocity data measured at 506 sites of the Central Asian GPS network. The most distinctive features of the estimated strain field are N-S shortening of the largest basins in the Tien Shan and at the junction between the Pamir and Tien Shan, as well as the westward motion of the eastern and western boundaries of the Pamir relative to the Tarim plate and Tajik depression.

Echocardiographic assessments of longitudinal left ventricular function in healthy English Springer spaniels

ObjectivesTo establish reference intervals for echocardiographic measures of longitudinal left ventricular function in adult English Springer spaniel (ESS) dogs. AnimalsThis study involved 42 healthy adult ESS. MethodsAnimals were prospectively recruited from a general practice population in the United Kingdom. Dogs were examined twice, at least 12 months apart, to exclude dogs with progressive cardiac disease. Mitral annular plane systolic excursion, tissue Doppler imaging mitral annular velocities and two-dimensional speckle-tracking echocardiographic left ventricular longitudinal strain and strain rate were measured. Intraoperator and intraobserver variability were examined and reference intervals were calculated. The potential effects of body weight, age and heart rate on these variables were examined. ResultsIntraoperator and intraobserver variability was <10% for all parameters except tissue Doppler imaging E′ (the peak velocity of early diastolic mitral annular motion as determined by pulsed wave Doppler) and two-dimensional speckle-tracking echocardiographic variables, which were all <20%. Thirty-nine dogs were used to create reference intervals. Significant (but mostly weak) effects of age, heart rate and body weight on were detected. Reference intervals were similar to previously published values in different breeds. Clinical significanceBreed specific reference intervals for measures of longitudinal left ventricular function in the ESS are presented.

CRT-400.05 Value Of Right Ventricular 2D-Speckle Tracking Parameters In Predicting The TIMI Flow Grade Of The RCA In Patients With Acute RV Infarction

Two-dimensional (2D) strain and strain rate (SR) analyses are novel Doppler-independent techniques to assess myocardial deformation. While this method has been frequently used to assess LV function, it has yet rarely been used to examine right ventricular (RV) function. This is a prospective study

Right ventricular strain before and after pulmonary thromboendarterectomy in patients with chronic thromboembolic pulmonary hypertension.

Right ventricular (RV) function is significantly impaired in patients with chronic thromboembolic pulmonary hypertension (CTEPH). Two-dimensional speckle tracking RV strain and strain rate are novel methods to assess regional RV systolic function in CTEPH patients before and after pulmonary thromboendarterectomy (PTE). Our goal was to (1) assess baseline longitudinal strain and strain rate of the basal RV free wall in CTEPH and (2) measure early changes in RV strain and strain rate after PTE. We performed echocardiography on 30 consecutive patients with CTEPH referred for PTE with adequate pre- and post-PTE strain imaging. Strain and strain rate were assessed 6.4 ± 4.5 days before and 9.1 ± 3.9 after PTE. Basal RV free wall strain and time to peak strain-but not basal RV strain rate and time to peak strain rate-changed significantly after PTE. Unexpectedly, basal RV strain became less negative, from -24.3% to -18.9% after PTE (P = 0.005). Time to peak strain decreased from 356 to 287 msec after PTE (P < 0.001). Preoperatively, RV strain correlated with pulmonary vascular resistance (PVR) and mean pulmonary artery pressure (mPAP) but this relationship was not evident postoperatively. Furthermore, the change in RV strain did not correlate with the change in mPAP or PVR. In patients with CTEPH, RV basal strain paradoxically became less negative (i.e., relative systolic shortening decreased) following PTE. This change in RV strain could be due to intraoperative RV ischemia and/or postoperative stunning. Thus, RV basal strain cannot be used as a surrogate marker for surgical success early after PTE.

The Influence of the Region of Interest Width on Two‐Dimensional Speckle Tracking–Based Measurements of Strain and Strain Rate

There are significant variations in the published normal values of two-dimensional speckle tracking-derived strain and strain rate. These occur even when authors use the same software. To measure strain, the operator creates a region of interest (ROI) to define the myocardium to be analyzed. The purpose of this study was to test the hypothesis that measurements vary significantly with the chosen ROI width. In 20 healthy subjects (11 males, mean age 17.6 ± 6.18 years) an apical four-chamber view (4CH) and parasternal short-axis view (SAX) were analyzed. Initially ROI width was set automatically by the software. Two subsequent measurements were obtained from each cine loop by choosing the ROI width one step narrower and one step wider than the automatic ROI width. The mean differences between the measurements of narrower and automatic ROI and between automatic and wider ROI were -1.8 ± 0.7% and -0.9 ± 0.5% for global longitudinal strain (SL), -2.2 ± 0.6% and -1.7 ± 0.7% for global circumferential strain (SC), -0.10 ± 0.06/sec and -0.07 ± 0.06/sec for global longitudinal strain rate (SrL), and -0.15 ± 0.09/sec and -0.12 ± 0.07/sec for global circumferential strain rate (SrC) (all P < 0.000). This corresponds to a relative difference to the mean of both measurements of -4.4 to -11.0%. Layer-specific myocardial deformation and curvature dependency lead to an inverse correlation between the chosen ROI width and strain and strain rate measurements. Just one step of ROI-width change leads to a significant bias. Precise ROI-width definition is essential but technical factors limit its feasibility.

Combination of a peroxisome proliferator-activated receptor-gamma agonist and an angiotensinII receptor blocker attenuates myocardial fibrosis and dysfunction in type2 diabetic rats.

We aimed to examine the effect of an angiotensinII receptor blocker (ARB), a peroxisome proliferator-activated receptor (PPAR)-gamma agonist, and their combination on myocardial fibrosis and function in type2 diabetic rats. Five male Long-Evans Tokushima Otsuka (LETO) rats and 20 male Otsuka Long-Evans Tokushima Fatty (OLETF) rats were used. OLETF rats were assigned to four groups (n=5 per group) at 28weeks-of-age: untreated, losartan-treated, rosiglitazone-treated and combination-treated. The ARB, losartan, was administered at a dose of 5mg/kg/day, and the PPAR-gamma agonist, rosiglitazone, was administered at a dose of 3mg/kg/day by oral gavage for 12weeks. Urine and blood samples were collected, and two-dimensional echocardiograms and strain rate imaging were obtained at 28 and 40weeks. Cytokines were evaluated by reverse transcriptase polymerase chain reaction, and histological analysis was carried out at 40weeks. At 40weeks, the global radial strains of the losartan-treated (55.7±4.5%, P=0.021) and combination-treated groups (59.3±6.7%, P=0.001) were significantly higher compared with the untreated OLETFs (44.3±10.5%). No difference was observed when compared with LETO rats. Although the rosiglitazone-treated group showed a better metabolic profile than the untreated OLETF group, there was no difference in the global radial strain (49.8±6.0 vs 44.3±10.5, P=0.402). The expression of pro-inflammatory cytokines, and collagen typeI and III were consistently attenuated in the losartan-treated and combination-treated OLETF groups, but not in the rosiglitazone-treated group. A combination of rosiglitazone and losartan attenuates myocardial fibrosis and dysfunction in type2 diabetic rats.

Two-Dimensional Atrial Systolic Strain Imaging Predicts Atrial Fibrillation at 4-Year Follow-Up in Asymptomatic Rheumatic Mitral Stenosis

The aim of this study was to assess systolic left atrial (LA) reservoir function in patients with mitral stenosis (MS) using two-dimensional (2D) strain (ε) and strain rate imaging and its prognostic value in predicting atrial fibrillation (AF) at 4-year follow-up. One hundred one asymptomatic patients with pure rheumatic MS and 70 healthy controls were evaluated using standard Doppler echocardiography (mitral valve area, mean gradient, systolic pulmonary pressure, LA width, LA volumes, and LA ejection fraction) and 2D speckle-tracking. LA width, volumes, and systolic pulmonary pressure were significantly increased (P < .0001), and LA 2D ε and strain rate were significantly impaired in patients with MS (P < .0001). At 4-year follow-up, 20 patients (20%) showed AF on standard electrocardiography or 24-hour Holter electrocardiography. Patients with MS who had AF were older than those who did not, without significant differences in LA dimensions, volumes, ejection fraction, and compliance index. Instead, atrial myocardial systolic 2D ε was significantly impaired in patients with events. On multivariate analysis (age, LA volume, planimetric mitral area, average annular Ea, and LA strain) the best predictor of AF was average LA peak systolic ε (coefficient, 0.43; SE, 0.098; P<.01), with an area under the receiver operating characteristic curve of 0.761 (SE, 0.085; 95% confidence interval, 0.587-0.888, P= .002) for a cutoff value of 17.4%. The results of 2D ε imaging are abnormal in patients with asymptomatic MS and predict AF at 4-year follow-up.

Time Course of Right Ventricular Remodeling after Percutaneous Atrial Septal Defect Closure: Assessment of Regional Deformation Properties with Two‐Dimensional Strain and Strain Rate Imaging

Quantitative assessment of the right ventricular (RV) function in atrial septal defect (ASD) patients before and after closure remains difficult. The aim of this study was to assess the regional RV function in ASD patients, to evaluate the extent and time course of RV remodeling following ASD closure, and to investigate whether any regional difference exists in RV remodeling. Twenty patients with ASD and 20 age-matched controls were included. All underwent standard echocardiography and two-dimensional strain (S) and strain rate (SR) imaging by speckle tracking before, and 24 hours and 1 month after the defect closure. Right ventricular S was higher in ASD patients except apical lateral segment S, which was lower when compared with controls. There was no difference in RV SR between ASD patients and controls. RV septal S and SR, and lateral SR decreased in 24 hours after the procedure and remained the same at 1 month. RV lateral basal and mid S decreased and apical S increased in 24 hours after the closure. All 3 segments showed some more increase at 1 month. RV apical S showed strong correlations with systolic pulmonary artery pressure and global RV systolic function indices. Chronic volume overload in ASD patients causes alterations in RV deformation. Percutaneous closure results in rapid remodeling and normalization of RV deformation. The major geometrical and deformational changes are completed in 24 hours. Lateral wall S seems to reflect the RV deformational changes due to volume loading and unloading better than SR in ASD patients.

Two-Dimensional Strain Rate and Doppler Tissue Myocardial Velocities: Analysis by Echocardiography of Hemodynamic and Functional Changes of the Failed Left Ventricle during Different Degrees of Extracorporeal Life Support

To evaluate hemodynamic and functional changes of the failed left ventricle by Velocity Vector Imaging (VVI) and tissue Doppler, 22 patients with cardiogenic shock supported by extracorporeal life support (ECLS) were imaged during ECLS output variations inducing severe load manipulations. The following data were acquired: (1) mean arterial pressure, aortic Doppler velocity-time integral, left ventricular end-diastolic volume, and mitral Doppler E wave; (2) tissue Doppler systolic (Sa) and early diastolic (Ea) velocities; and (3) systolic peak velocity (Sv), strain, and strain rate using VVI. Load variations were documented by a significant decrease in afterload (mean arterial pressure, -21%), an increase in preload (left ventricular end-diastolic volume, +12%; E, +46%; E/Ea ratio, +22%), and an increase in the velocity-time integral (+45%). VVI parameters increased (Sv, +36%; strain, +81%; and strain rate, +67%; P < .05), unlike tissue Doppler systolic velocities (+2%; P = NS). Whatever the ECLS flow, Sa was higher in patients who survived. VVI parameters are not useful in characterizing the failed left ventricle with rapidly varying load conditions. Tissue Doppler systolic velocities appear to be load independent and thus could help in the management of ECLS patients.