Reference Values for Myocardial Two-Dimensional Strain Echocardiography in a Healthy Pediatric and Young Adult Cohort

Assessment of left ventricular functions with tissue Doppler, strain, and strain rate echocardiography in patients with familial Mediterranean fever

OBJECTIVE

This study assessed the early changes in regional and global systolic and diastolic myocardial functions in patients with familial Mediterranean fever without any cardiovascular symptoms using tissue Doppler and strain and strain rate echocardiography and compared them to the results of a control group.

METHODS

This study has a cross-sectional and observational design. FMF patients with normal left ventricular function were included in the study. We excluded patients who had arrhythmia, acquired/congenital heart disease, pericarditis, or acute attack. We compared 45 children with familial Mediterranean fever on colchicine therapy and 45 age- and sex-matched healthy children.

RESULTS

The 45 patients with familial Mediterranean fever included 24 (55.3%) girls and 21 (46.7%) boys with a mean age of 11.3 ± 3.7 (range 2-18) years. The mean disease duration was 4.6 ± 2.4 (range 0.5-10) years. In the patient group, the homozygous M694V mutation was the most common (64.4%) mutation. The patients with familial Mediterranean fever had statistically lower longitudinal global strain, radial global strain, and strain rates (-14.44 ± 4.77%, 14.80 ± 6.29%, and 0.59 ± 0.24 s, respectively) than the controls (-17.40 ± 1.79%, 17.53 ± 4.63%, and 0.83 ± 0.51 s) (p < 0.05). The circumferential global strain did not differ significantly between the groups.

CONCLUSION

Patients with familial Mediterranean fever who are subclinical from a cardiac aspect might have normal left ventricular function as measured by conventional echocardiography. However, the disease affects their myocardial tissue, and these patients should be followed with conventional, strain, and strain rate echocardiography techniques regularly.

Normal Range of Left Ventricular Strain, Dimensions and Ejection Fraction Using Three-dimensional Speckle-Tracking Echocardiography in Neonates

Aims:

Three-dimensional speckle-tracking echocardiography (3D-STE) is a promising new technique to evaluate left ventricular (LV) mechanics. The feasibility and normal values of LV strain using 3D-STE have recently been established in adults and children. Unfortunately, no data are available in neonates. The aims of this study were to evaluate the feasibility and establish normal values of 3D LV volumes, ejection fraction (EF), and the 4 normal strains in healthy neonates.

Materials and Methods:

Of 50 consecutive newborns who were delivered at our hospital or returned to their first newborn follow-up within the first 3 weeks of life, 38 babies underwent full echocardiographic evaluation, including the acquisition of at least 3 full volume data sets from the apical window, while naturally sleeping. Data sets were analyzed offline. Global LV longitudinal, circumferential, and radial strain, as well as 3D LV volumes and EF, were measured using 3D-STE.

Results:

Of the 50 newborns, 2 patients were excluded because of significant intra-cardiac shunts, and in another 10 subjects, parents did not give consent. At least one data set was adequate for analysis in all the remaining subjects. Mean indexed LV diastolic, systolic volumes, and EF were 24.7 ± 3.6 ml/m², 9.2 ± 1.3 ml/m², and 63% ± 3.7%, respectively. Normal global longitudinal, circumferential, radial, and tangential 4D strain were −20.9% ± 2.8%, −32.4% ± 3.1%, 44.3% ± 3.4%, and −39.7% ± 3.4%, respectively.

Conclusions:

3D-STE is feasible in newborns without the needed for sedation. Reference values of normal, regional, and global LV 4D strain and volumes were obtained.

Abnormal circumferential strain measured by echocardiography is present in patients with Shwachman-Diamond syndrome despite normal shortening fraction

BACKGROUND

Shwachman-Diamond Syndrome (SDS) is an autosomal recessive disorder characterized by bone marrow failure and exocrine pancreatic dysfunction. Heart failure has been described in patients with SDS. Circumferential strain (ε(cc)) is a measure of cardiac performance that may identify dysfunction when standard measures are normal.

PROCEDURES

Patients with SDS were identified and the echocardiographic database queried. Cardiac anatomy and function were recorded, and ε(cc) was measured retrospectively.

RESULTS

From 1995-2013, 27 patients with biallelic SBDS mutations confirming the diagnosis of SDS were identified at our institution: 14 had at least one echocardiogram available; 10 underwent HSCT, with echocardiograms available in nine. Ejection fraction (EF) was normal in all 14 patients evaluated; however, ε(cc) was decreased in 4/12 studies prior to HSCT. In two patients, ε(cc) was abnormal both before and after HSCT, in one, ε(cc) changed from normal to abnormal after HSCT, and in one, ε(cc) was normal after HSCT despite being abnormal prior. Echocardiogram reports were also available for six patients in the North American SDS registry, all with normal EF.

CONCLUSIONS

While EF was normal in all patients with SDS, ε(cc) was abnormal in 33% prior to HSCT and 33% of those who had undergone HSCT. This suggests that SDS is associated with systolic dysfunction. Further studies are needed to define the incidence of dysfunction in this group and the progression to heart failure.

Echocardiographic assessment of ventricular function in pediatric patients: a comprehensive guide

Assessment of ventricular function is an important part of every echocardiographic examination. Specific pediatric guidelines on quantification of ventricular function are available, but technology evolves quickly and it generally takes long before newer techniques are integrated into routine clinical practice and are adopted by the guidelines. In the current overview, we would like to present our experience with integrating newer echocardiographic techniques for assessing ventricular function in children using a comprehensive state-of-the-art echocardiographic functional protocol. This protocol is used for specific patient populations such as pediatric patients with cardiomyopathy, post-transplant patients and oncology patients. We present the practical aspects of the protocols, their rationale and how this can be applied in clinical practice.

Two-dimensional speckle-tracking-derived segmental peak systolic longitudinal strain identifies regional myocardial involvement in patients with myocarditis and normal global left ventricular systolic function

The presence of myocardial late gadolinium enhancement (LGE) by cardiac magnetic resonance (CMR) imaging in concert with electrocardiography and elevated biomarkers helps support the diagnosis of acute myocarditis. Two-dimensional echocardiography is limited to global and qualitative regional function assessment and may not contribute to the diagnosis, especially in the presence of normal LV systolic function. Two-dimensional speckle-tracking (2D-STE)-derived segmental peak systolic (pkS) longitudinal strain (LS) may identify segmental myocardial involvement in myocarditis. We sought to identify an association between segmental pkS, LGE, and troponin levels in patients with myocarditis. Retrospective analysis of myocardial segmental function by 2D-STE segmental strain was compared to the presence of LGE and admission peak troponin levels in patients with acute myocarditis and preserved global LV systolic function. American Heart Association 17-segment model was used for comparison between imaging modalities. Global function was assessed by m-mode-derived shortening fraction (SF). Descriptive statistics and regression analysis were utilized. Forty-four CMRs performed to evaluate for myocarditis were identified. Of the 44, 10 patients, median age 17.5 years (14-18.5 years) and median SF 35 % (28-44 %), had paired CMR and 2D-STE data for analysis, and 161/170 segments could be analyzed by both methods for comparison. PkS LS was decreased in 51 % of segments that were positive for LGE with average pkS of -14.7 %. Segmental pkS LS abnormalities were present in all but one patient who had abnormal pkS circumferential strain. Global pkS LS was decreased in patients with myocarditis. There is a moderate correlation between decreased pkS LS and the presence of LGE by CMR, 2D-STE for myocardial involvement in acute myocarditis can serve as an useful noninvasive adjunct to the existing tests used for the diagnosis of acute myocarditis and might have a role in prognostication.

Markers of cardiovascular risk, insulin resistance, and ventricular dysfunction and remodeling in obese adolescents

OBJECTIVES

To test our hypothesis that obese adolescents have left ventricular (LV) dysfunction and remodeling that are associated with markers of cardiovascular risk and insulin resistance (IR).

STUDY DESIGN

In a cross-sectional study of 44 obese and 14 lean age-, sex-, Tanner stage-, and race-matched adolescents, IR, markers of cardiovascular risks, conventional and 2-dimensional speckle tracking echocardiography measures of LV function and structure were evaluated and compared.

RESULTS

The obese adolescents had significantly increased body mass index Z-score, systolic blood pressure, fasting insulin, IR, and atherogenic lipids compared with the lean adolescents. A subgroup of obese adolescents had LV remodeling characterized by significantly increased LV mass index (g/m(2.7)) and relative wall thickness. Almost all obese adolescents had LV dysfunction with peak LV global longitudinal strain (GLS, %), systolic GLS rate (GLSR, %/s), and early diastolic GLSR significantly lower than in lean adolescents and in the normal pediatric population. Body mass index Z-score predicted LV remodeling (LV mass index [R(2) = 0.34] and relative wall thickness [R(2) 0.10]), and peak LV GLS (R(2) 0.15), and along with systolic blood pressure, predicted systolic GLSR (R(2) 0.16); (P ≤ .01 for all). Fasting insulin predicted early diastolic GLSR (R(2) 0.17, P ≤ .01).

CONCLUSIONS

Obese adolescents have subclinical ventricular dysfunction associated with the severity of obesity, increased systolic blood pressure, and IR. Ventricular remodeling is present in a subgroup of obese adolescents in association with the severity of obesity. These findings suggest that obesity may have an early impact on the cardiovascular health of obese adolescents.

Young Women With Abdominal Obesity Have Subclinical Myocardial Dysfunction

BACKGROUND

Abdominal obesity is an independent risk factor for cardiovascular disease. The effect of abdominal obesity on myocardial function in young obese women remains unknown. Therefore, we aimed to investigate cardiac morphology and function, myocardial deformation, and mechanical indices, in young women with and without abdominal obesity.

METHODS

Cross-sectional analyses of 39 women with abdominal obesity (waist circumference ≥ 80 cm) and 33 nonobese control subjects (waist circumference < 80 cm) aged 18-30 years underwent conventional echocardiographic measures of cardiac morphology and function together with tissue Doppler, and 2-dimensional speckle tracking measures of myocardial deformation and mechanics. Cardiometabolic risk factors including anthropometric, hypertension, biochemistry, and fitness were also assessed.

RESULTS

Standard echocardiography results for cardiac morphology and function were similar between groups, with the exception of larger left atrial dimensions in women with abdominal obesity (P ≤ 0.05). Compared with control subjects, women with abdominal obesity also demonstrated reduced systolic and diastolic mitral annular plane velocities, increased left atrial pressure surrogates (E/diastolic mitral annular plane velocity), and prolonged timing measures of diastolic function including isovolumic relaxation time and transmitral deceleration time (P ≤ 0.05). In addition, longitudinal strain and diastolic strain rate were reduced in women with abdominal obesity (P ≤ 0.05) but circumferential deformation and myocardial mechanics (twist indices and rotation) were preserved. Markers of abdominal obesity retained an independent direct correlation with parameters of cardiac dysfunction, explaining 12%-39% of the overall variability.

CONCLUSIONS

A young, otherwise healthy group of women with abdominal obesity displayed subclinical cardiac dysfunction indicated using selected tissue Doppler imaging and speckle tracking echocardiography measures.

Anomalous origin of left coronary artery from pulmonary artery associated with pulmonary hypertension

This is a report on a 10-year-old child with anomalous origin of left coronary artery (LCA) from pulmonary artery (ALCAPA), severe pulmonary hypertension (PH), old myocardial infarction and poor intercoronary collateralization. It discusses the echocardiographic pitfalls in this particular setting and introduces a new echocardiographic view (posterior pulmonary cusp view) for visualization of the anomalous origin of LCA from the posterior pulmonary cusp (PC) in patients with ALCAPA from the PC of the pulmonary artery. We describe three echocardiographic pitfalls that can mislead the echocardiographer and two helpful hints that guide the clinician to the correct diagnosis. The survival of this child shows that limited size of left ventricular myocardial infarction and severe mitral regurgitation in early infancy can result in a life-saving pulmonary hypertension which preserves viability and function of left ventricle despite lack of intercoronary collateral arteries. After one year follow-up, she is doing well on medical treatment.

Development of left ventricular longitudinal speckle tracking echocardiography in very low birth weight infants with and without bronchopulmonary dysplasia during the neonatal period

Objectives

In preterm infants, postnatal myocardial adaptation may be complicated by bronchopulmonary dysplasia (BPD). We aimed to describe the development of left ventricular function by serial 2D, Doppler, and speckle tracking echocardiography (2D-STE) in infants with and without BPD during the neonatal period and compare these to anthropometric and conventional hemodynamic parameters.

Study Design

Prospective echocardiography on day of life (DOL) 1, 7, 14, and 28 in 119 preterm infants <1500 g birth weight of whom 36 developed BPD (need for oxygen supplementation at 36 weeks gestational age). Non-BPD and BPD infants differed significantly in median (IQR) gestational age (25.5(24–26.5) weeks vs. 29(27–30) weeks, p<0.001) and birth weight (661(552–871) g vs. 1100(890–1290) g, p<0.001).

Results

The intra- and inter-observer variability of the 2D-STE parameters measured did not depend on time of measurement, although there were significant differences in the reproducibility of the parameters. Low intra- and inter-observer variability was seen for longitudinal systolic strain and strain rate mid septum with a median CV (coefficient of variation) of <4.6%. Much higher CVs (>10%) were seen for the apical segment. While anthropometric parameters show rapid development during the first 4 weeks of life, the speckle tracking parameters did not differ statistically significantly during the neonatal period. Infants with and without BPD differed significantly (p<0.001) in the development of anthropometric parameters, conventional hemodynamic parameters except for heart rate, and 2D-STE parameters: global longitudinal systolic strain rate (GLSSR) and longitudinal systolic strain for the mid left wall (LSSR). The largest differences were seen at DOL 1 and 7 in GLSSR (p<0.001) and in LSSR (p<0.01).

Conclusions

Reproducible 2D-STE measurements are possible in preterm infants <1500 g. Cardiac deformation reveals early (DOL 1 and 7) ventricular changes (GLSSR and LSSR) in very low birth weight infants who develop BPD.

Association of hypercholesterolemia and cardiac function evaluated by speckle tracking echocardiography in a rabbit model

Background

Although hypercholesterolemia is a major risk factor for coronary artery disease (CAD), only limited data are available regarding its direct effect on myocardial function apart from CAD. The aim of this study was to evaluate LV systolic function using speckle-tracking echocardiography and investigate the relationship between hypercholesterolemia and myocardial function.

Methods

Twenty-eight rabbits were randomly divided into three groups: 8 were fed normal chow for 3 months (group 1) and the remaining 20 were fed an atherogenic diet for 2 (group 2) or 3 months (group 3). Global systolic radial, circumferential and longitudinal peak strain were calculated. Serum total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) and myocardial cholesterol levels were measured.

Results

Global systolic longitudinal strain were both decreased in the group 2 and 3 (P < 0.001), whereas radial strain were increased (P < 0.001) compared with group 1. Global circumferential strain in the group 3 was significantly reduced (P < 0.001). Serum and myocardial cholesterol concentration markedly increased in the group 2 and group 3 (P < 0.001). There was a significant inverse correlation between longitudinal strain and serum TC, LDL-C as well as myocardial cholesterol levels (r = - 0.723, r = - 0.794, r = - 0.700, P both < 0.001). A significant negative correlation was also noted between circumferential strain and serum TC, LDL-C as well as myocardial cholesterol levels (r = - 0.518, P = 0.007; r = - 0.691, P < 0.001; r = - 0.659, P < 0.001). A significant positive correlation was found between radial strain and serum TC, LDL-C as well as myocardial cholesterol levels (r = 0.432, P = 0.028; r = 0.602, P = 0.001; r = 0.469, P = 0.016).

Conclusion

Although LV morphology and ejection fractions were not different among the three groups, elevated concentration of cholesterol, especially in serum LDL-C, was significantly associated with LV systolic dysfunction. The findings also indicate that reductions in longitudinal was the first appeared, followed by circumferential, and was compensated for by increasing radial strain.

Tissue motion annular displacement of the mitral valve using two-dimensional speckle tracking echocardiography predicts the left ventricular ejection fraction in normal children

BACKGROUND

The gold standard for determining the left ventricular ejection fraction is cardiac magnetic resonance imaging. Other parameters for determining the ejection fraction such as M-mode echocardiography are operator-dependant and often inaccurate. Assessment of the displacement of the mitral valve annulus using two-dimensional speckle tracking echocardiography may provide an accurate and simple method of determining the left ventricular ejection fraction in children.

METHOD

We retrospectively studied 70 healthy 9-year-old children with no history of cardiovascular disease who had been assessed using cardiac magnetic resonance imaging and two-dimensional transthoracic echocardiography. Mitral displacement was determined using the tissue motion annular displacement (TMAD) feature of Philips QLAB version 9. The midpoint displacement of the mitral valve was calculated, and the predicted left ventricular ejection fraction was compared with magnetic resonance imaging-derived and M-mode-derived ejection fractions.

RESULTS

The mean ejection fraction derived from magnetic resonance imaging (64.5 (4.6)) was similar to that derived from the TMAD midpoint (60.9 (2.7), p = 0.001) and the M-mode (61.9 (7), p = 0.012). The TMAD midpoint correlated strongly with the magnetic resonance imaging-derived ejection fraction (r = 0.69, p < 0.001), as did the predicted fraction (r = 0.67, p < 0.001). The M-mode ejection fraction showed a poor linear correlation with both magnetic resonance imaging-derived and TMAD-derived fractions (r = 0.33 and 0.04, respectively).

CONCLUSION

TMAD of the mitral valve is a simple, effective, and highly reproducible method of assessing the ejection fraction in normal children. It shows a strong linear correlation with magnetic resonance imaging-derived ejection fraction and is superior to M-mode-derived ejection fractions.

Functional assessment for congenital heart disease

Significant improvement in survival of children with congenital cardiac malformations has resulted in an increasing population of adolescent and adult patients with congenital heart disease. Of the long-term cardiac problems, ventricular dysfunction remains an important issue of concern. Despite corrective or palliative repair of congenital heart lesions, the right ventricle, which may be the subpulmonary or systemic ventricular chamber, and the functional single ventricle are particularly vulnerable to functional impairment. Regular assessment of cardiac function constitutes an important aspect in the long-term follow up of patients with congenital heart disease. Echocardiography remains the most useful imaging modality for longitudinal monitoring of cardiac function. Conventional echocardiographic assessment has focused primarily on quantification of changes in ventricular size and blood flow velocities during the cardiac cycles. Advances in echocardiographic technologies including tissue Doppler imaging and speckle tracking echocardiography have enabled direct interrogation of myocardial deformation. In this review, the issues of ventricular dysfunction in congenital heart disease, conventional echocardiographic and novel myocardial deformation imaging techniques, and clinical applications of these techniques in the functional assessment of congenital heart disease are discussed.

Speckle tracking echocardiography in very preterm infants: feasibility and reference values

BACKGROUND

Speckle tracking echocardiography (STE) applies computer software analysis on images generated by conventional ultrasound to define and follow a cluster of speckles from frame to frame and calculates parameters of motion (velocity, displacement) and deformation (strain, strain rate). We explored STE of the left ventricle in stable very preterm infants.

METHODS

Apical 4 chamber clips (4CH) and short axis clips (SAX) at the level of the papillary muscle were analyzed using TomTec software with manual tracing of cardiac borders. The software automatically segmented the ventricle into 6 equidistant segments and provided segmental and global analysis of deformation parameters. Tracking accuracy was scored visually.

RESULTS

Seventy-four clips from 51 infants with a median gestational age of 28weeks were analyzed. Feasibility of 4CH was 95.5% for longitudinal and 96.2% for radial parameters. The reliability of longitudinal and circumferential deformation parameters was good, but radial parameters were less reliable. 4CH mean (SD) global peak systolic longitudinal and radial strain (%) and strain rate (s(-1)) were -18.7(2.6), -1.73(0.28), 23.6(9.1) and 1.94(0.65), and SAX circumferential and radial strain and strain rate were -19.5(3.7), -1.97(0.46), 32.1(14.4) and 2.37(0.80).

CONCLUSION

STE is feasible in preterm infants. Optimal image acquisition is paramount. Longitudinal parameters in 4CH and circumferential in SAX were most robust.

Normal ranges of right ventricular systolic and diastolic strain measures in children: a systematic review and meta-analysis

BACKGROUND

Establishment of the range of normal values and associated variations of two-dimensional (2D) speckle-tracking echocardiography (STE)-derived right ventricular (RV) strain is a prerequisite for its routine clinical application in children. The objectives of this study were to perform a meta-analysis of normal ranges of RV longitudinal strain measurements derived by 2D STE in children and to identify confounders that may contribute to differences in reported measures.

METHODS

A systematic review was conducted in PubMed, Embase, Scopus, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov. Search hedges were created to cover the concepts of pediatrics, STE, and the right heart ventricle. Two investigators independently identified and included studies if they reported the 2D STE-derived RV strain measure RV peak global longitudinal strain, peak global longitudinal systolic strain rate, peak global longitudinal early diastolic strain rate, peak global longitudinal late diastolic strain rate, or segmental longitudinal strain at the apical, middle, and basal ventricular levels in healthy children. Quality and reporting of the studies were assessed. The weighted mean was estimated using random effects with 95% confidence intervals (CIs), heterogeneity was assessed using Cochran's Q statistic and the inconsistency index (I(2)), and publication bias was evaluated using funnel plots and Egger's test. Effects of demographic, clinical, equipment, and software variables were assessed in a metaregression.

RESULTS

The search identified 226 children from 10 studies. The reported normal mean values of peak global longitudinal strain among the studies varied from -20.80% to -34.10% (mean, -29.03%; 95% CI, -31.52% to -26.54%), peak global longitudinal systolic strain rate varied from -1.30 to -2.40 sec(-1) (mean, -1.88 sec(-1); 95% CI, -2.10 to -1.59 sec(-1)), peak global longitudinal early diastolic strain rate ranged from 1.7 to 2.69 sec(-1) (mean, 2.34 sec(-1); 95% CI, 2.00 to 2.67 sec(-1)), and peak global longitudinal late diastolic strain rate ranged from 1.00 to 1.30 sec(-1) (mean, 1.18 sec(-1); 95% CI, 1.04 to 1.33 sec(-1)). A significant base-to-apex segmental strain gradient (P < .05) was observed in the RV free wall. There was significant between-study heterogeneity and inconsistency (I(2) > 88% and P < .01 for each strain measure), which was not explained by age, gender, body surface area, heart rate, frame rate, tissue-tracking methodology, 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 = .59).

CONCLUSIONS

This study is the first to define normal values of 2D STE-derived RV strain in children on the basis of a meta-analysis. The normal mean value in children for RV global strain is -29.03% (95% CI, -31.52% to -26.54%). The normal mean value for RV global systolic strain rate is -1.88 sec(-1) (95% CI, -2.10 to -1.59 sec(-1)). RV segmental strain has a stable base-to-apex gradient that highlights the dominance of deep longitudinal layers of the right ventricle that are aligned base to apex. Variations among different normal ranges did not appear to be dependent on differences in demographic, clinical, or equipment parameters in this meta-analysis. All of the eligible studies used equipment and software from one manufacturer (GE Healthcare).

Update on cardiac imaging techniques 2012

Cardiac imaging is one of the basic pillars of modern cardiology. The potential list of scenarios where cardiac imaging techniques can provide relevant information is simply endless so it is impossible to include all relevant new features of cardiac imaging published in the literature in 2012 in the limited format of a single article. We summarize the year's most relevant news on cardiac imaging, highlighting the ongoing development of myocardial deformation and 3-dimensional echocardiography techniques and the increasing use of magnetic resonance imaging and computed tomography in daily clinical practice.

Normal left ventricular mechanics by two-dimensional speckle-tracking echocardiography. Reference values in healthy adults

INTRODUCTION AND OBJECTIVES

Two-dimensional speckle-tracking echocardiography is a novel tool to assess myocardial function. The purpose of this study was to evaluate left ventricular myocardial strain and rotation parameters by two-dimensional speckle-tracking echocardiography in a large group of healthy adults across a wide age range to establish their reference values and to assess the influence of age, sex, and hemodynamic factors.

METHODS

Transthoracic echocardiograms were acquired in 247 healthy volunteers (139 women, 44 years [standard deviation, 16 years old] (range, 18-80 years). We measured longitudinal, circumferential, and radial peak systolic strain values, and left ventricular rotation and twist.

RESULTS

Average values of global longitudinal, radial, and circumferential strain were -21.5% (standard deviation, 2.0%), 40.1% (standard deviation, 11.8%) and -22.2% (standard deviation, 3.4%), respectively. Longitudinal strain was significantly more negative in women, whereas radial and circumferential strain and rotational parameters were similar in both sexes. Accordingly, lower limits of normality for the strain components were -16.9% in men and -18.5% in women for longitudinal strain, and -15.4% for circumferential and 24.6% for radial strain, irrespective of sex. Longitudinal strain values were more negative at the base than at apical segments. Mean rotational values were -6.9° (standard deviation, 3.5°) for the base, 13.0° (standard deviation, 6.5°) for apical rotation, and 20.0° (standard deviation, 7.3°) for net twist.

CONCLUSIONS

We report the comprehensive assessment of normal myocardial deformation and rotational mechanics in a large cohort of healthy volunteers. We found that women have more negative longitudinal strain, accounting for their higher left ventricular ejection fraction. Availability of reference values for these parameters may foster their implementation in the clinical routine.

Advanced echocardiographic imaging of the congenitally malformed heart

There have been significant advancements in the ability of echocardiography to provide both morphological and functional information in children with congenitally malformed hearts. This progress has come through the development of improved technology such as matrix array probes and software which allows for the off line analysis of images to a high standard. This article focuses on these developments and discusses some newer concepts in advanced echocardiography such is multi-planar reformatting [MPR] and tissue motion annular displacement [TMAD].

Our aim is to discuss important aspects related to the quality and reproducibility of data, to review the most recent published data regarding advanced echocardiography in the malformed heart and to guide the reader to appropriate text for overcoming the technical challenges of using these methods. Many of the technical aspects of image acquisition and post processing have been discussed in recent reviews by the authors and we would urge readers to study these texts to gain a greater understanding [1]. The quality of the two dimensional image is paramount in both strain analysis and three dimensional echocardiography. An awareness of how to improve image quality is vital to acquiring accurate and usable data.

Three dimensional echocardiography (3DE) is an attempt to visualise the dynamic morphology of the heart. Although published media is the basis for theoretical knowledge of how to practically acquire images, electronic media [eg.www.3dechocardiography.com] is the only way of visualising the advantages of this technology in real time.

It is important to be aware of the limitations of this technology and that much of the data gleaned from using these methods is at a research stage and not yet in regular clinical practice.

The influence of the region of interest width on two-dimensional speckle tracking-based measurements of strain and strain rate

AIMS

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.

METHODS AND RESULTS

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%.

CONCLUSION

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.

What can three-dimensional speckle-tracking echocardiography contribute to evaluate global left ventricular systolic performance in patients with heart failure?

PURPOSE

Three-dimensional speckle-tracking echocardiography (3D-STE) is a newly developed technique to evaluate left ventricular (LV) deformation by measuring the area strain (AS) of endocardial surface that combines information from both longitudinal (LS) and circumferential strain (CS). We performed a study to examine myocardial deformation in patients with heart failure (HF) using 3D-STE.

METHOD

A total of 149 subjects including 58 patients with HF and preserved ejection fraction (HFPEF), 45 patients with HF and reduced ejection fraction (HFREF), and 46 normal subjects were prospectively studied by 3D-STE.

RESULT

After adjusting for age, gender and BSA, global CS, LS, radial strain (RS) and AS derived from 3D-STE in patients with HFPEF were significantly higher than their counterparts in patients with HFREF (all p<0.001), but lower than that in normal subjects (all p<0.05). In addition, among all the strain parameters, global AS exhibited the highest correlation with LV ejection fraction (y=1.243x+6.332, r=0.982, p<0.001) and the best intra- (ICCs: 0.986, p<0.001) and inter-observer variability (ICCs: 0.978, p<0.001) than other parameters of 3D strain (CS: 0.981 and 0.974; LS: 0.908 and 0.841; RS: 0.946 and 0.915; all p<0.001).

CONCLUSIONS

Measurement of endocardial surface AS based on 3D-STE technique is reproducible and proves to be accurate and comprehensive in assessing the global LV performance and multidirectional deformation of the LV myocardium in HF patients.

Ventricular performance after surgery for a congenital heart defect as assessed using advanced echocardiography: from doppler flow to 3D echocardiography and speckle-tracking strain imaging

A varying degree of impairment of ventricular performance is observed over the long-term after surgery for a congenital heart defect (CHD). Impaired ventricular performance has been shown to be of prognostic value for increased risk of cardiovascular events in adult CHD patients. This emphasizes the importance of delineating the timing and cause of this postoperative impairment. Impairment of ventricular performance could develop over time as a consequence of residua, sequelae and complications of the CHD or surgical procedure. Yet, impaired ventricular performance has also been observed immediately after surgery and can persist and/or worsen over time. This postoperative impairment of ventricular performance is the focus of this review. This article provides an overview of echocardiographic techniques currently used to assess ventricular performance. Furthermore, we review current literature describing ventricular performance, as assessed using echocardiography, after correction of a CHD. In general, a decrease in ventricular performance is observed directly after surgery for CHD’s. Subsequent follow-up of ventricular performance is characterized by a varying degree of postoperative recovery. A consistent observation is the persistent impairment of right-ventricular performance after repair in several different subgroups of CHD patients ranging from ventricular septal defect repair to surgery for Tetralogy of Fallot.

Longitudinal follow-up of ventricular performance in healthy neonates

BACKGROUND

Specific follow-up of newly introduced echocardiographic parameters in healthy neonates and infants is limited.

AIM

To prospectively describe follow-up of left ventricular (LV) tissue Doppler imaging (TDI) and speckle tracking strain parameters in healthy subjects up to two months after birth.

DESIGN

This is a longitudinal follow-up study.

SUBJECTS

Twenty-eight (10 male) healthy newborns were included and underwent transthoracic echocardiography 1-3 days, 3 weeks and 6-7 weeks after birth.

OUTCOME MEASURES

In each echocardiogram, parameters describing cardiac growth, including LV mass (LVM), were assessed. Additionally, TDI derived peak systolic velocity (S') and peak early (E') and late (A') diastolic velocities were assessed in the basal LV free wall and interventricular septum (IVS). Finally LV longitudinal, radial and circumferential global peak strain parameters were assessed using speckle tracking strain imaging.

RESULTS

LVM significantly increased during follow-up (7.6 ± 2.4 versus 12.4 ± 3.2g, p = 0.002). Similarly at 1-3 days versus 6-7 weeks after birth, an increase in LV and IVS systolic (LV S' 4.1 ± 1.5 versus 6.3 ± 1.5 cm/s, p = 0.001; IVS S' 3.6 ± 0.9 versus 6.4 ± 1.3 cm/s, p < 0.001) and diastolic (LV E' 6.1 ± 2.2 versus 9.7 ± 2.9 cm/s, p = 0.002; IVS E' 5.1 ± 1.4 versus 10.7 ± 3.3 cm/s, p < 0.001) TDI parameters was observed. In contrast, global peak longitudinal, radial and circumferential strain parameters did not significantly change during follow-up.

CONCLUSIONS

A significant increase in LV systolic and diastolic TDI parameters was observed up to two months after birth. Yet this increase may be (cardiac) growth-dependent. No significant changes were observed in speckle tracking strain derived global peak strain parameters; this may render the technique particularly valuable in evaluation of LV systolic performance during periods of significant growth, such as the neonatal period.

Age-related normal range of left ventricular strain and torsion using three-dimensional speckle-tracking echocardiography

BACKGROUND

Three-dimensional (3D) speckle-tracking echocardiography (STE) is an emerging technology used to quantify left ventricular (LV) function. However, the accuracy and normal values of LV strain and twist using 3D STE have not been established in a large group of normal subjects. The aims of this study were to (1) to evaluate the accuracy of 3D STE analysis of LV strain against a cardiac magnetic resonance (CMR) reference and (2) to establish age-related normal values of LV strain and torsion using real-time 3D echocardiographic (RT3DE) images.

METHODS

In protocol 1, RT3DE data sets and CMR images were acquired on the same day in 19 patients referred for clinically indicated CMR. Global LV longitudinal, circumferential, and radial strain was compared between the two modalities. In protocol 2, global and regional strain and twist and torsion were measured in 313 healthy subjects using 3D STE.

RESULTS

In protocol 1, good correlations for each LV strain component were noted between RT3DE imaging and CMR (r = 0.61-0.86, P < .001). In protocol 2, normal global longitudinal, circumferential, radial, and 3D strain were -20.3 ± 3.2%, -28.9 ± 4.6%, 88.0 ± 21.8%, and -37.6 ± 4.8%, respectively. A significant age dependency was observed for global longitudinal and 3D strain. Aging also affected LV torsion: the lowest values were found in children and adolescents, and values subsequently increased with age, while further aging was associated with a gradual reduction in basal rotation accompanied by an increase in apical rotation.

CONCLUSIONS

This study provides initial validation of 3D strain analysis from RT3DE images and reference values of normal 3D LV strain and torsion. The age-related differences in LV strain and torsion may reflect myocardial maturation and aging.

Left ventricular three-dimensional global systolic strain by real-time three-dimensional speckle-tracking in children: feasibility, reproducibility, maturational changes, and normal ranges

BACKGROUND

Three-dimensional (3D) strain analysis may help overcome the limitations of Doppler and two-dimensional strain analysis for the left ventricle and become the method of choice for left ventricular (LV) systolic function. The aims of this study were to evaluate the feasibility and reproducibility of LV global 3D systolic strain by real-time 3D speckle-tracking echocardiography (STE) in children and to establish their maturational growth patterns and normal values.

METHODS

A prospective study was conducted in 256 consecutive healthy subjects using real-time 3D echocardiography. Full-volume 3D data were acquired using a 3D matrix-array transducer. Three-dimensional LV peak systolic global strain (GS), global longitudinal strain (GLS), global radial strain (GRS), and global circumferential strain (GCS) values were determined using real-time 3D STE.

RESULTS

A total of 228 patients (89%) met the criteria for analysis; 28 (11%) were excluded. The correlations between age and strain variables by real-time 3D STE were poor (R(2) = 0.01-0.05, P < .05). The differences in GLS and GCS among the five age groups were statistically significant but clinically irrelevant. There were no statistical differences in GRS and GS values among the age groups, nor were there statistical differences between the genders for all 3D strain parameters. Intraobserver and interobserver variability ranged from 5.0 ± 4.3% to 10.1 ± 8.5% versus 6.9 ± 6.1% to 17.0 ± 16.2% for coefficients of variation, respectively. Interclass correlation coefficients ranged from 0.78 to 0.87 and from 0.75 to 0.79 for intraobserver and interobserver measurements for GS, GLS, GCS, and GRS, respectively.

CONCLUSIONS

LV global 3D systolic strain analysis using the new 3D STE is feasible and reproducible in the pediatric population. There are small maturational changes in GLS and GCS, but not in GRS and GS, that are statistically significant but probably clinically irrelevant. Further investigation is warranted for potential clinical application of this new technology in a pediatric population.

Diffuse myocardial fibrosis by T1-mapping in children with subclinical anthracycline cardiotoxicity: relationship to exercise capacity, cumulative dose and remodeling

BACKGROUND

The late cardiotoxic effects of anthracycline chemotherapy influence morbidity and mortality in the growing population of childhood cancer survivors. Even with lower anthracycline doses, evidence of adverse cardiac remodeling and reduced exercise capacity exist. We aim to examine the relationship between cardiac structure, function and cardiovascular magnetic resonance (CMR) tissue characteristics with chemotherapy dose and exercise capacity in childhood cancer survivors.

METHODS

Thirty patients (15 ± 3 years), at least 2 years following anthracycline treatment, underwent CMR, echocardiography, and cardiopulmonary exercise testing (peak VO(2)). CMR measured ventricular function, mass, T(1) and T(2) values, and myocardial extracellular volume fraction, ECV, a measure of diffuse fibrosis based on changes in myocardial T1 values pre- and post-gadolinium. Cardiac function was also assessed with conventional and speckle tracking echocardiography.

RESULTS

Patients had normal LVEF (59 ± 7%) but peak VO(2) was 17% lower than age-predicted normal values and were correlated with anthracycline dose (r = -0.49). Increased ECV correlated with decreased mass/volume ratio (r = -0.64), decreased LV wall thickness/height ratio (r = -0.72), lower peak VO(2)(r = -0.52), and higher cumulative dose (r = 0.40). Echocardiographic measures of systolic and diastolic function were reduced compared to normal values (p < 0.01), but had no relation to ECV, peak VO(2) or cumulative dose.

CONCLUSIONS

Myocardial T1 and ECV were found to be early tissue markers of ventricular remodeling that may represent diffuse fibrosis in children with normal ejection fraction post anthracycline therapy, and are related to cumulative dose, exercise capacity and myocardial wall thinning.

Second trimester ultrasound: reference values for two-dimensional speckle tracking-derived longitudinal strain, strain rate and time to peak deformation of the fetal heart

BACKGROUND

Data on myocardial deformation during the internationally widely used second-trimester screening are scarce and confusing. Reference values of time to peak strain are missing. The aims of this study were to assess reference values derived from two-dimensional speckle-tracking echocardiography for global and regional longitudinal right ventricular (RV) and left ventricular (LV) strain, strain rate, and time to peak global strain and to determine the influence of heart rate and gender on these strain parameters.

METHODS

Seventy-five healthy fetuses were enrolled during second-trimester ultrasound (20-24 weeks). Clips with high frame rates (mean, 132 frames/sec) and two-dimensional (B-mode) grayscale images of apical or basal four-chamber views of both ventricles were used for offline analyses.

RESULTS

There were no statistically significant differences in global strain and strain rate between both ventricles (P = .679 and P = .734, respectively) or among the RV, septal, and LV free walls. Regional measurements, modeled also as an interaction of wall and segment (basal mid and apical), showed only a small, statistically significant difference between the basal RV and LV free walls. Strain and strain rate values were independent of heart rate. The mean time to peak LV global strain adjusted for heart rate was statistically significantly shorter than the RV value (P < .0001]). Strain, strain rate, and time to peak global strain were not found to be associated with gender.

CONCLUSIONS

The establishment of second-trimester two-dimensional speckle-tracking echocardiographic reference values for global and regional strain, strain rate, and time to peak global strain in a healthy fetal cohort is a mandatory prerequisite for its use in evaluating (pathologic) changes in both ventricular functions during pregnancy.

Assessment of intraventricular time differences in healthy children using two-dimensional speckle-tracking echocardiography

BACKGROUND

Parameters describing intraventricular time differences are increasingly assessed in both adults and children. However, to appreciate the implications of these parameters in children, knowledge of the applicability of adult techniques in children is essential. Hence, the aim of this study was to assess the applicability of speckle-tracking strain-derived parameters in children, paying special attention to age and heart rate dependency.

METHODS

One hundred eighty-three healthy subjects (aged 0-19 years) were included. Left ventricular global peak strain, time to global peak strain, and parameters describing intraventricular time differences were assessed using speckle-tracking strain imaging in the apical two-chamber, three-chamber, and four-chamber views (longitudinal strain) and the parasternal short-axis view (radial and circumferential strain). Parameters describing intraventricular time differences included the standard deviation of time to peak strain and differences in time to peak strain between two specified segments. Age and heart rate dependency were evaluated using regression analysis, and intraobserver and interobserver variability were tested.

RESULTS

Acquisition and analysis of longitudinal six-segment time-strain curves was successful in 94.8% of subjects and radial and circumferential time-strain curves in 89.5%. No clinically significant linear relation was observed between age or heart rate and parameters describing intraventricular time differences. The coefficient of variation of time to global peak strain parameters was <10, while it was >10 for parameters describing intraventricular time differences.

CONCLUSIONS

The feasibility of speckle-tracking strain analysis in children is relatively good. Furthermore, no linear relation was observed between age or heart rate and parameters describing intraventricular time differences. However, the limited reproducibility of some parameters describing intraventricular time differences will confine their applicability in clinical practice.

Nomograms for blood flow and tissue Doppler velocities to evaluate diastolic function in children: a critical review

Interest in diastolic function in children has increased recently. However, the strengths and limitations of published pediatric nomograms for echocardiographic diastolic parameters have not been critically evaluated, especially in the neonatal population. A literature search was performed within the National Library of Medicine using the keywords normal/reference values, power Doppler/tissue Doppler velocities, and children/neonates. The search was further refined by adding the keywords diastolic function, myocardial, mitral/tricuspid inflow, pulmonary vein, and Tei index. Thirty-three published studies evaluating diastolic function in normal children were included in this review. In many studies, sample sizes were limited, particularly in terms of neonates. There was heterogeneity in the methodologies to perform and normalize measurements and to express normalized data (Z scores, percentiles, and mean values). Although most studies adjusted measurements for age, classification by specific age subgroups varied, and few addressed the relationships of measurements to body size and heart rate (especially with higher neonatal heart rates). Although reference values were reproducible in older children, they varied significantly in neonates and infants. Pediatric diastolic nomograms are limited by small sample sizes and inconsistent methodologies for the performance and normalization of measurements, with few data on neonates. Some studies do reveal reproducible patterns in diastolic function in older children. A comprehensive pediatric nomogram of diastolic function involving a large population of normal infants and older children and using standardized methodology is warranted and would have tremendous impact in the care of children with acquired and congenital heart disease.

Normal ranges of left ventricular strain: a meta-analysis

BACKGROUND

The definition of normal values of left ventricular global longitudinal strain (GLS), global circumferential strain, and global radial strain is of critical importance to the clinical application of this modality. The investigators performed a meta-analysis of normal ranges and sought to identify factors that contribute to reported variations.

METHODS

MEDLINE, Embase, and the Cochrane Library database were searched through August 2011 using the key terms "strain," "speckle tracking," "left ventricle," and "echocardiography" and related phrases. Studies were included if the articles reported left ventricular strain using two-dimensional speckle-tracking echocardiography in healthy normal subjects, either in the control group or as a primary objective of the study. Data were combined using a random-effects model, and effects of demographic, hemodynamic, and equipment variables were sought in a meta-regression.

RESULTS

The search identified 2,597 subjects from 24 studies. Reported normal values of GLS varied from -15.9% to -22.1% (mean, -19.7%; 95% CI, -20.4% to -18.9%). Normal global circumferential strain varied from -20.9% to -27.8% (mean, -23.3%; 95% CI, -24.6% to -22.1%). Global radial strain ranged from 35.1% to 59.0% (mean, 47.3%; 95% CI, 43.6% to 51.0%). There was significant between-study heterogeneity and inconsistency. The source of variation was sought between studies using meta-regression. Blood pressure, but not age, gender, frame rate, or equipment, was associated with variation in normal GLS values.

CONCLUSIONS

The narrowest confidence intervals from this meta-analysis were for GLS and global circumferential strain, but individual studies have shown a broad range of strain in apparently normal subjects. Variations between different normal ranges seem to be associated with differences in systolic blood pressure, emphasizing that this should be considered in the interpretation of strain.

New imaging modalities to assess cardiac function: not just pretty pictures

PURPOSE OF REVIEW

The following review will focus on the current advances in both echocardiography and cardiovascular MRI (CMRI) in the assessment of cardiac function.

RECENT FINDINGS

The assessment of cardiac function in pediatric patients and in congenital heart disease (CHD) patients has dramatically improved over the last several years. The advancement of transthoracic echocardiography with tissue Doppler imaging, speckle tracking, and three-dimensional echocardiography has enabled strain assessment and the ability to estimate ventricular volumes in these complex patients. In the last few decades, CMRI has become an imaging modality that is now part of the standard tools used for cardiac assessment. With superb two-dimensional and three-dimensional resolution, CMRI allows clear delineation of cardiac and extracardiac structures as well as accurate and reproducible assessment of ventricular volume and function. The most recent and robust contributions of CMRI are its ability to provide characterization of the myocardium and the development of new measurements of global and regional myocardial mechanics and function.

SUMMARY

Recent advances in echocardiography and CMRI allow a better understanding of myocardial mechanics and composition as well as accurate assessment of ventricular volume and global and regional function in the complex and unique anatomy often found in CHD patients.