Mean Global Circumferential Strain Research Articles

Global and regional cardiac magnetic resonance feature tracking left ventricular strain analysis in assessing early myocardial disease in β thalassemia major patients

BackgroundCardiac magnetic resonance imaging (CMR) is the modality of choice for quantification of myocardial iron overload in β-thalassemia major patients using the T2* sequence. CMR feature tracking (FT) is a recent magnetic resonance imaging tool that gives an idea about myocardial fibers deformation; thus, it can detect early impairment in myocardial function even before the reduction in ejection fraction.MethodsThis study aims to assess the ability of left ventricular CMR-FT in the early detection of systolic dysfunction in β thalassemia major patients and to correlate it with the degree of myocardial iron overload measured by CMR T2*. This prospective study enrolled 57 β thalassemia major patients who received long-term blood transfusion and 20 healthy controls. CMR was used to evaluate left ventricular volumes, ejection fraction, and the amount of myocardial T2*. A two-dimensional left ventricular FT analysis was performed. Both global and segmental left ventricular strain values were obtained.ResultsThe mean global circumferential strain (GCS) and global radial strain (GRS) values were significantly lower in patients compared to control (P = 0.002 and P = 0.006, respectively). No correlation was found between T2* values and ejection fraction; however, there was a significant correlation between T2* values and GCS and GRS (P = 0.012 and P = 0.025, respectively) in thalassemia patients. Regional strain revealed significantly lower values of GCS and GRS in basal regions compared to apical ones (P = 0.000).ConclusionsOur study revealed that CMR-FT can play a role in the early detection of systolic impairment in thalassemia patients.

Correlation of myocardial strain by CMR-feature tracking with substrate abnormalities detected by electro-anatomical mapping in patients with nonischemic cardiomyopathy

BackgroundLate gadolinium enhancement (LGE) detected by cardiac MRI (CMR) has low correlation with low voltage zones (LVZs) detected by electroanatomical mapping (EAM). We aim to study correlation of myocardial strain by CMR- Feature Tracking (FT) alongside LGE with LVZs detected by EAM.MethodsNineteen consecutive CMRs of patients with EAM were analyzed offline by CMR-FT. Peak value of circumferential strain (CS), longitudinal strain (LS), and LGE was measured in each segment of the left ventricle (17-segment model). The percentage of myocardial segments with CS and LS > −17% was determined. Percentage area of LGE-scar was calculated. Global and segment–wise bipolar and unipolar voltage was collected. Percentage area of bipolar LVZ (<1.5 mV) and unipolar LVZ (<8.3 mV) was calculated.ResultsMean age was 62±11 years. Mean LVEF was 37±13%. Mean global CS was −11.8±5%. Mean global LS was −11.2±4%. LGE-scar was noted in 74% of the patients. Mean percentage area of LGE-scar was 5%. There was significant correlation between percentage abnormality detected by LS with percentage bipolar LVZ (r = +0.5, p = 0.03) and combined percentage CS+LS abnormality with percentage unipolar LVZ (r = +0.5, p = 0.02). Per-unit increase in CS increased the percentage area of unipolar LVZ by 2.09 (p = 0.07) and per-unit increase in LS increased the percentage area of unipolar LVZ by 2.49 (p = 0.06). The concordance rates between CS and LS to localize segments with bipolar/unipolar LVZ were 79% and 95% compared to 63% with LGE.ConclusionsMyocardial strain detected by CMR-FT has a better correlation with electrical low voltage zones than the conventional LGE.

Increased circumferential deformation predicts cardiac events when left ventricular ejection fraction is normal

Abstract Background Recent research suggests that early left ventricular (LV) systolic dysfunction is characterized by compromised longitudinal function and a concomitant augmentation of circumferential deformation expressed as increased global circumferential strain (GCS). It is hypothesized that increased GCS could be used to identify people at higher risk of cardiovascular events when left ventricular ejection fraction (LVEF) is preserved. Purpose The present study aimed to investigate whether elevated GCS in individuals with preserved LVEF predicts major adverse cardiovascular events (MACE). Methods A total of 2,874 participants from the general population were included in this prospective cohort study. All participants had echocardiography performed and analyzed. Exclusion criteria were HF at baseline, non-sinus rhythm during echocardiography, and inadequate image quality for GCS assessment. Outcome was MACE including incident heart failure, myocardial infarction, and/or cardiovascular death. Absolute values of strain were used. To determine the optimal transition point of a potential effect modification, Cox regression models with different LVEF thresholds were created. The model with the optimal hazard ratio (HR) and P values of the interaction terms and Akaike information criterion was chosen. Results Mean age was 53±18 years and 60% were female. Mean LVEF and GCS were 57±6% and 21.6±4.0%, respectively. Median follow-up was 3.5 years [IQR: 2.6; 4.4] and a total of 92 (3.2%) developed MACE. A U-shaped relationship was observed between GCS and MACE. The lowest incidence rate was within the GCS range of 20 to 25% (Figure 1a). A significant interaction (P&amp;lt;0.001) between GCS and LVEF was observed regarding MACE. The optimal transition point for this effect modification was determined to be LVEF=50%. In multivariable Cox regressions (including conventional cardiovascular risk factors and global longitudinal strain (GLS)), increasing GCS was significantly associated with future MACE in participants with LVEF ≥50% (HR=1.09 [95% CI: 1.01; 1.17] per 1% increase, n=2420) while decreasing GCS were associated with a higher risk of MACE in individuals with abnormal LVEF (HR=1.16 [95% CI: 1.04; 1.29] per 1% decrease, n=289) (Figure 1b). A total of 50 (2.1%) developed the MACE amongst the participants with LVEF ≥50%. This group had significantly lower GLS (19.0±2.7% vs 19.9±2.0%, P=0.013) and ratio of peak early transmitral filling velocity to peak early diastolic tissue velocity (E/e') (10.7 [IQR: 7.9; 14.3] vs 6.5 [5.3; 8.4], P&amp;lt;0.001) compared to the participants that did not develop MACE with normal LVEF. Figure 2 illustrates a model of the development of GCS, LVEF, GLS, and E/e' as LV function declines. Conclusion In the general population, the prognostic value of GCS is modified by LVEF. In participants with normal LVEF, higher GCS was associated with increased risk of MACE, while the opposite was observed in participants with abnormal LVEF. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): The Copenhagen City Heart Study is funded by The Danish Heart FoundationThe Metropolitan Region of Denmark (public funding).

The relationship between myocardial microstructure and strain in chronic infarction using cardiovascular magnetic resonance diffusion tensor imaging and feature tracking

BackgroundCardiac diffusion tensor imaging (cDTI) using cardiovascular magnetic resonance (CMR) is a novel technique for the non-invasive assessment of myocardial microstructure. Previous studies have shown myocardial infarction to result in loss of sheetlet angularity, derived by reduced secondary eigenvector (E2A) and reduction in subendocardial cardiomyocytes, evidenced by loss of myocytes with right-handed orientation (RHM) on helix angle (HA) maps. Myocardial strain assessed using feature tracking-CMR (FT-CMR) is a sensitive marker of sub-clinical myocardial dysfunction. We sought to explore the relationship between these two techniques (strain and cDTI) in patients at 3 months following ST-elevation MI (STEMI).Methods32 patients (F = 28, 60 ± 10 years) underwent 3T CMR three months after STEMI (mean interval 105 ± 17 days) with second order motion compensated (M2), free-breathing spin echo cDTI, cine gradient echo and late gadolinium enhancement (LGE) imaging. HA maps divided into left-handed HA (LHM, − 90 < HA < − 30), circumferential HA (CM, − 30° < HA < 30°), and right-handed HA (RHM, 30° < HA < 90°) were reported as relative proportions. Global and segmental analysis was undertaken.ResultsMean left ventricular ejection fraction (LVEF) was 44 ± 10% with a mean infarct size of 18 ± 12 g and a mean infarct segment LGE enhancement of 66 ± 21%. Mean global radial strain was 19 ± 6, mean global circumferential strain was − 13 ± − 3 and mean global longitudinal strain was − 10 ± − 3. Global and segmental radial strain correlated significantly with E2A in infarcted segments (p = 0.002, p = 0.011). Both global and segmental longitudinal strain correlated with RHM of infarcted segments on HA maps (p < 0.001, p = 0.003). Mean Diffusivity (MD) correlated significantly with the global infarct size (p < 0.008). When patients were categorised according to LVEF (reduced, mid-range and preserved), all cDTI parameters differed significantly between the three groups.ConclusionChange in sheetlet orientation assessed using E2A from cDTI correlates with impaired radial strain. Segments with fewer subendocardial cardiomyocytes, evidenced by a lower proportion of myocytes with right-handed orientation on HA maps, show impaired longitudinal strain. Infarct segment enhancement correlates significantly with E2A and RHM. Our data has demonstrated a link between myocardial microstructure and contractility following myocardial infarction, suggesting a potential role for CMR cDTI to clinically relevant functional impact.

Abstract 12136: Detection of Sub-Clinical Left Ventricular Dysfunction in COVID-19 Patients

Introduction: Abnormalities of left ventricular (LV) strain have been shown to occur prior to impairment of global left ventricular function, measured by global LV ejection fraction (EF). Although first described in patients receiving cardiotoxic chemotherapy, impairment of LV strain prior to a decrease in EF has also been shown in many other disease states which affect LV function. This study was designed to assess impairment of LV strain in post COVID-19 patients with normal EF using cardiac MRI MyoStrain Fast-SENC (strain encoded) pulse sequences. Methods: An institutional cardiac imaging database was queried for all patients with documented COVID-19 test positivity and a normal LVEF &gt;= 55% who underwent measurement of global longitudinal strain (GLS), global circumferential strain (GCS), and regional longitudinal and circumferential strain using cardiac MRI Fast-SENC pulse sequences. Global and regional strain measurements were compared to a cohort of healthy volunteers who also underwent CMR Fast-SENC imaging. Abnormal myocardial strain was defined as a value &gt;-17%. Results: Of 50 COVID-19 patients in the cardiac imaging database who underwent CMR Fast-SENC imaging, 40 had a normal LVEF, constituting the study cohort. Mean GLS and GCS for the study cohort were -16.40% and -15.45% and for healthy volunteers were -19.71% and -20.93% respectively; both comparisons were statistically significant with an unpaired t-test (p&lt;0.01). Furthermore, the prevalence of abnormal LV strain in COVID-19 patients with normal LVEF was 77.78%. Conclusions: These data suggest that impairment of LV strain (longitudinal and circumferential) occurs in COVID-19 patients who have a normal LVEF. Whether a decrease in GLS and/or GCS precede a decrease in LVEF, is beyond the scope of this study. However, the ability to evaluate progression of LV strain abnormalities with CMR may help identify changes in LV function before the onset of a reduction in LVEF and development of heart failure. The ability to identify and quantify abnormal left ventricular GLS and GCS with cardiac MRI also opens the door to assess any benefit of therapy, including anti-inflammatory agents, anti-viral drugs and steroids.

Evidence of occult right ventricular dysfunction in morbidly obese patients

Abstract Background Abnormalities of right ventricular (RV) strain have been shown to occur prior to impairment of global right ventricular function, measured by global RV ejection fraction (RVEF) in patients with increased RV afterload, such as pulmonary hypertension. Obesity is a form of increased afterload involving both the right and left cardiac circulations, raising suspicion that impaired RV strain may be an early indicator of myocardial dysfunction. Purpose This study was designed to assess impairment of RV strain in obese patients with normal right ventricular ejection fraction (RVEF) using cardiac MRI Fast SENC (strain encoded) pulse sequences. Methods An institutional cardiac imaging database was queried for all patients with body mass index (BMI) greater than 35 kg/m2 who underwent measurement of RV global longitudinal strain (GLS), RV global circumferential strain (GCS) and 37 segmental strain measurements using cardiac MRI Fast-SENC pulse sequences. Global RVEF was computed for all patients using a standard cardiac MRI method using non-automated hand drawn RV endocardial borders. Global and regional strain measurements were compared to a cohort of healthy volunteers who also underwent CMR Fast-SENC imaging. Abnormal myocardial strain was defined as a value greater than −17%. Results Of the 356 patients in the database, 48 had a BMI greater than 35 kg/m2. Mean RV GLS and GCS for the study cohort were −16.6 and −15.8 respectively. For healthy volunteers RV GLS and GCS were −20.8 and −19.0 respectively. Comparison of mean RV GLS and GCS of both groups were statistically significant ANOVA p&amp;lt;0.001. The number of normal RV segmental strain values was significantly decreased in obese patients when compared to the normal cohort, ANOVA p&amp;lt;0.001 (Figure 1). Furthermore, the prevalence of abnormal RV GCS in morbidly obese patients with normal RVEF greater than or equal to 40% was 84% (21 of 25 patients). Conclusions These findings suggest that morbidly many obese patients have occult RV dysfunction despite a normal RVEF. This occult RV dysfunction not only affects RV global GLS and GCS, but also the percentage of normal segmental strain values. Detection of occult RV dysfunction is of clinical significance in that it may provide an opportunity for treatment before development of symptomatic right heart failure. Figure 1 Funding Acknowledgement Type of funding source: None

Two-dimensional systolic speckle tracking echocardiography provides a noninvasive aid in the identification of acute pediatric heart transplant rejection.

Acute rejection is an important cause of morbidity and mortality in the pediatric heart transplant (HT) population. A reliable noninvasive method for diagnosis of clinical rejection could substantially reduce these negative outcomes. Evaluate left ventricular (LV) global longitudinal strain (GLS), and global circumferential strain (GCS) as early noninvasive indicators of acute pediatric HT rejection. An 18-month prospective cohort study involving 61 patients evaluated absolute change in peak global systolic strain (GLS and GCS) from enrollment (baseline) to next planned clinical encounter (follow-up) or rejection. Acute rejection defined as a biopsy of grade≥2R or treatment with enhanced immunosuppression by the transplant team, blinded to strain analysis. Two patient cohorts three months post HT without evidence of rejection at enrollment were identified. The study cohort experienced rejection. The control cohort remained free from rejection on follow-up. Two-way analysis of variance (ANOVA) models evaluated change in GLS and GCS by cohort group and time. Applying exclusion criteria, 51 patients enrolled in the control cohort and 10 in the study cohort. The study cohort's mean GLS declined 33% from baseline to rejection (P<.001) and mean GCS declined 16.6% (P=.021). No significant change from baseline to follow-up was seen in the control cohort. A threshold absolute GLS value of 16.1% identified acute rejection with 100% sensitivity and 98% specificity (Likelihood Ratio, [LR] 51). Noninvasive global longitudinal strain was sensitive and specific in the identification of acute clinical rejection in pediatric HT recipients.

Comparison of left ventricular systolic function by 2D speckle-tracking echocardiography between normal pregnant women and pregnant women with preeclampsia.

Introduction: In light of previous studies reporting the significant effects of preeclampsia on cardiac dimensions, we sought to evaluate changes in the left ventricular (LV) systolic and diastolic functions in patients with preeclampsia with a view to investigating changes in cardiac strain. Methods: This cross-sectional study evaluated healthy pregnant women and pregnant women suffering from preeclampsia who were referred to our hospital for routine healthcare services. LV strain was measured by 2D speckle-tracking echocardiography. Results: Compared with the healthy group, echocardiography in the group with preeclampsia showed a significant increase in the LV end-diastolic diameter (47.43 ± 4.94 mm vs 44.84 ± 4.30 mm; P = 0.008), the LV end-systolic diameter (31.16 ± 33.3 mm vs 29.20 ± 3.75 mm; P = 0.008), and the right ventricular diameter (27.93 ± 1.71 mm vs 24.53 ± 23.3; P = 0.001). The mean global longitudinal strain was -18.69 ± 2.8 in the group with preeclampsia and -19.39 ± 3.49 in the healthy group, with the difference not constituting statistical significance (P = 0.164). The mean global circumferential strain in the groups with and without preeclampsia was -20.4 ± 12.4 and -22.68 ± 5.50, respectively, which was significantly lower in the preeclampsia group (P = 0.028). Conclusion: The development of preeclampsia was associated with an increase in the right and left ventricular diameters, as well as a decrease in the ventricular systolic function, demonstrated by a decline in global circumferential strain.

Left Ventricular Myocardial Deformation on Cine MR Images: Relationship to Severity of Disease and Prognosis in Light-Chain Amyloidosis.

Purpose To measure left ventricular (LV) myocardial strain with cine magnetic resonance (MR) imaging and a deformable registration algorithm (DRA) and to assess the prognostic value of myocardial strain in patients with light-chain (AL) amyloidosis. Materials and Methods In this prospective study, 78 consecutive patients with AL amyloidosis who underwent contrast material-enhanced cardiac MR imaging were enrolled at West China Hospital. LV myocardial strains and late gadolinium enhancement (LGE) were evaluated. Association between myocardial strain and all-cause mortality was analyzed with the stepwise Cox regression model. Results Global longitudinal strain (GLS) and global circumferential strain (GCS) were significantly lower in the no or nonspecific LGE group compared with the subendocardial LGE and transmural LGE groups (mean GLS, -10% ± 3 [standard deviation] vs -7% ± 3 vs -4% ± 1; P < .001) (mean GCS, -13% ± 3 vs -11% ± 3 vs -7% ± 2; P < .001). GLS and GCS were reduced in patients without clinical cardiac amyloidosis (mean GLS, -13% ± 3 vs -16% ± 2; P = .005) (mean GCS, -16% ± 1 vs -19% ± 2; P = .02). Circumferential and radial strains were impaired in basal segments in accordance with the distribution of LGE. Multivariate Cox analysis revealed that GCS (hazard ratio [HR] = 1.16 per 1% absolute decrease; 95% confidence interval [CI]: 1.03, 1.31; P = .02) and the presence of transmural LGE (HR = 1.75; 95% CI: 1.10, 2.80; P = .02) were independent predictors of all-cause mortality after adjustment for LV ejection fraction, right ventricular ejection fraction, LV mass index, GLS, and global radial strain. Conclusion Strain parameters derived with cine MR imaging-based DRA may be a new noninvasive imaging marker with which to evaluate the extent of cardiac amyloid infiltration and may offer independent prognostic information for all-cause mortality in patients with AL amyloidosis.

111 New normal ranges and superior reproducibility of 3d myocardial strain on cardiovascular magnetic resonance-feature tracking

BackgroundMyocardial deformation can be key to clinical decision. 2D feature-tracking of cardiovascular magnetic resonance (CMR-FT) imaging is user-friendly but has poor reproducibility, particularly for radial strain. 3D CMR-FT may improve...

Reference Ranges of Left Ventricular Strain Measures by Two-Dimensional Speckle-Tracking Echocardiography in Children: A Systematic Review and Meta-Analysis

Establishment of the range of reference values and associated variations of two-dimensional speckle-tracking echocardiography (2DSTE)-derived left ventricular (LV) strain is a prerequisite for its routine clinical adoption in pediatrics. The aims of this study were to perform a meta-analysis of normal ranges of LV global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS) measurements derived by 2DSTE in children and to identify confounding factors that may contribute to variance in reported measures. A systematic review was launched in MEDLINE, Embase, Scopus, the Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Library. Search hedges were created to cover the concepts of pediatrics, STE, and left-heart ventricle. Two investigators independently identified and included studies if they reported 2DSTE-derived LV GLS, GCS, or GRS. The weighted mean was estimated by using random effects models with 95% CIs, heterogeneity was assessed using the Cochran Q statistic and the inconsistency index (I(2)), and publication bias was evaluated using the Egger test. Effects of demographic (age), clinical, and vendor variables were assessed in a metaregression. The search identified 2,325 children from 43 data sets. The reported normal mean values of GLSamong the studies varied from -16.7% to -23.6% (mean, -20.2%; 95% CI, -19.5% to -20.8%), GCS varied from -12.9% to -31.4% (mean, -22.3%; 95% CI, -19.9% to -24.6%), and GRS varied from 33.9% to 54.5% (mean, 45.2%; 95% CI, 38.3% to 51.7%). Twenty-six studies reported longitudinal strain only from the apical four-chamber view, with a mean of -20.4% (95% CI, -19.8% to -21.7%). Twenty-three studies reported circumferential strain (mean, -20.3%; 95% CI, -19.4% to -21.2%) and radial strain (mean, 46.7%; 95% CI, 42.3% to 51.1%) from the short-axis view at the midventricular level. A significant apex-to-base segmental longitudinal strain gradient (P<.01) was observed in the LV free wall. There was significant between-study heterogeneity and inconsistency (I(2)>94% and P<.001 for each strain measure), which was not explained by age, gender, body surface area, blood pressure, heart rate, frame rate, frame rate/heart rate ratio, tissue-tracking methodology, location of reported strain value along the strain curve, ultrasound equipment, or software. The metaregression showed that these effects were not significant determinants of variations among normal ranges of strain values. There was no evidence of publication bias (P=.40). This study defines reference values of 2DSTE-derived LV strain in children on the basis of a meta-analysis. In healthy children, mean LV GLS was -20.2% (95% CI, -19.5% to -20.8%), mean GCS was -22.3% (95% CI, -19.9% to -24.6%), and mean GRS was 45.2% (95% CI, 38.3% to 51.7%). LV segmental longitudinal strain has a stable apex-to-base gradient that is preserved throughout maturation. Although variations among different reference ranges in this meta-analysis were not dependent on differences in demographic, clinical, or vendor parameters, age- and vendor-specific referenced ranges were established as well.

Left Ventricular Longitudinal and Circumferential Layer-Specific Myocardial Strains and Their Determinants in Healthy Subjects.

The reference values and impact of physiologic variables on echocardiographic quantification of left ventricular (LV) longitudinal and circumferential layer-specific myocardial strains in large series of healthy persons remain unknown. This study prospectively investigated the impact of age, gender, and other physiologic parameters on LV longitudinal and circumferential layer-specific myocardial strains. 119 healthy volunteers (age range, 22-76; 50% women) underwent echocardiography. Short-axis (for circumferential strain) and apical (for longitudinal strain) views were analyzed using modified speckle tracking software enabling the analysis of strains in three myocardial layers. In normal subjects, longitudinal and circumferential strain was highest in the endocardium and lowest in the epicardium, longitudinal and circumferential three-layer strain was highest in the apex and lowest in the base. The mean global longitudinal strain in the endocardial layer (GLS-endo), in the mid-myocardial layer (GLS-mid) and in the epicardial layer (GLS-epi) were -24.3 ± 3.1%, -21.3 ± 2.9%, and -18.9 ± 2.8%, respectively. Gender, HR, and SV (stroke volume) were independent predictors of GLS-endo, GLS-mid, and GLS-epi. The mean global circumferential strain in the endocardial layer (GCS-endo), in the mid-myocardial layer (GCS-mid) and in the epicardial layer (GCS-epi) were -34.3 ± 4.4%, -20.5 ± 3.0%, and -11.8 ± 2.7%, respectively. HR independently predicted GCS-endo, GCS-mid, and GCS-epi. Three-layer analysis of longitudinal and circumferential strain using two-dimensional speckle tracking imaging (2DSTI) can be performed on a clinical basis and may become an important method for the assessment of real time, quantitative global, and regional LV function.

Strain Analysis during Exercise in Patients with Left Ventricular Hypertrophy: Impact of Etiology

Hypertrophic cardiomyopathy (HCM) and aortic stenosis (AS) may influence left ventricular (LV) systolic function, despite preservation of LV ejection fraction. The aim of this study was to determine the relative importance of cardiac afterload and myocardial hypertrophy in the potential dysfunction of myocardial deformation, at rest and during standardized exercise. Patients with moderate to severe (≤ 1.5 cm(2)) asymptomatic AS and patients with HCM in sinus rhythm were prospectively studied using resting and exercise echocardiography during submaximal exercise. Myocardial deformations were assessed using two-dimensional strain. Exclusion criteria were altered LV ejection fraction (<50%), coronary artery disease, intra-LV obstruction > 30 mm Hg at rest, diastolic LV thickness ≥ 30 mm, and New York Heart Association class > II. Thus, 50 patients (25 with AS, 25 with HCM) were selected and matched for age, sex, rest and exercise blood pressure, degree of LV hypertrophy (defined by maximal wall thickness), and LV ejection fraction. Mean resting global longitudinal strain (GLS) was -14.9 ± 4.7% in patients with AS and -16.1 ± 3.9% in those with HCM (P = .30). During exercise (mean heart rate, 110 ± 10 beats/min), mean GLS was -13.9 ± 4.2% in patients with AS and -18.1 ± 5.4% in those with HCM (P = .004). GLS decreased in patients with AS but increased in those with HCM (ΔGLS, 0.9 ± 3.1% and -1.9 ± 3.2%, respectively, P = .003). The same results were observed for global circumferential strain. Mean resting global circumferential strain was -16.4 ± 5.8% in patients with AS and -17.9 ± 4.5% in those with HCM (P = .36). During exercise, mean global circumferential strain was -13.8 ± 4.1% in patients with AS and -18.6 ± 5.3% in those with HCM (P = .011). Afterload was higher, particularly during exercise, in patients with AS than in those with HCM. Longitudinal and circumferential LV deformation during exercise was lower in patients with AS compared with those with HCM, despite similar resting characteristics. The greater afterload observed in patients with AS led to reduced contractile reserve.

Global Circumferential Strain by 2-Dimensional Speckle Tracking Method for the Evaluation of the Left Ventricular Function

Background and Objectives: The speckle tracking method using 2-dimensional (2D) echocardiography is not affected by the tethering of neighboring segments and angulation. Global circumferential strain (GCS) of the left ventricle (LV) has been suggested as a systolic index and correlated with LV contractility. The purpose of this study was to investigate whether acute changes in preload affect global circumferential strain and to evaluate the usefulness of GCS by the speckle tracking method. Subjects and Methods: 2D echocardiography was performed in 69 patients with end-stage renal disease before and after hemodialysis to measure the LV end-diastolic volume and LV ejection fraction. 2D images were acquired from the short-axis view of the mid-LV for the evaluation of GCS. Results: Mean LV end-diastolic volume significantly decreased from 91.2±33.3 mL to 72.3±32.0 mL (p< 0.05), and LV ejection fraction decreased from 63.6±13.1% to 60.0±11.2% (p=0.006) after hemodialysis. However, mean GCS showed no significant change after hemodialysis (17.2±5.3% vs. 16.6±4.7%, p=0.13). GCS was found to be well correlated with LV ejection fraction (r=0.54, p<0.05) and peak systolic mitral annular velocity (r=0.46, p=0.000), but not with LV preload (r=0.06, p=0.622). Conclusion: GCS using the speckle tracking method is a useful index for the evaluation of LV systolic function because it is not affected by acute preload change and is correlated with LV ejection fraction and peak systolic mitral annular velocity. (Korean Circ J 2008;38:379-386)