Assessment of Regional Right Ventricular Velocities, Strain, and Displacement in Normal Children Using Velocity Vector Imaging

Velocity Vector Imaging Assessment of Functional Change in the Right Ventricle during Transcatheter Closure of Atrial Septal Defect by Intracardiac Echocardiography

The functional change of the right ventricle (RV) after atrial septal defect (ASD) via transcatheter closure is well known. We assessed the immediate RV functional change using velocity vector imaging (VVI) with intracardiac echocardiography (ICE). Seventy-four patients who underwent transcatheter closure of an ASD were enrolled. VVI in the “home view” of ICE showing the RV was obtained before and after the procedure. Velocity, strain, strain rate (SR), and longitudinal displacement were analyzed from VVI data, and the changes of these parameters before and after the procedure were compared. The velocity of the RV decreased after ASD transcatheter closure (3.97 ± 1.48 to 3.56 ± 1.4, p = 0.024), especially in the RV inlet and outlet. The average strain decreased (−19.21 ± 5.79 to −16.87 ± 5.03, p = 0.002), as did the average SR (−2.28 ± 0.64 to −2.03 ± 0.61, p = 0.006). The average longitudinal displacement did not differ. With the VVI technique, we could clearly observe RV functional change immediately after transcatheter closure of the ASD. RV functional change with regional difference may reflect the heterogeneity of volume reduction and suggest subclinical RV dysfunction. These findings can enhance our understanding of the physiologic changes in the RV during reverse remodeling.

Echocardiography vs cardiac magnetic resonance imaging assessment of the systemic right ventricle for patients with d-transposition of the great arteries status post atrial switch

OBJECTIVE

Patients with Dextro-transposition of the great arteries status post atrial switch (dTGA s/p atrial switch) are "at-risk" for systemic right ventricular (RV) dysfunction. Due to complex RV geometry, echocardiography (Echo) does not allow accurate determination of ejection fraction (EF), but cardiac magnetic resonance imaging (CMR) allows quantitative right ventricular assessment. Measures of ventricular deformation may be precursors to global ventricular dysfunction. The primary aim of this study was to characterize imaging and clinical findings for adult patients with dTGA s/p atrial switch.

DESIGN

This was a retrospective cohort study of patients with dTGA s/p atrial switch operation (February 1966 to August 1988) with CMR performed at Children's Hospital of Wisconsin (from September 2005 to May 2015). Eligible patients had clinic visit, Echo, and exercise stress test within 1 year of CMR.

RESULTS

This study enrolled twenty-seven patients (16 males, 11 females) with dTGA s/p atrial switch (18 with Mustard operation and 9 with Senning operation; median age 30 years; 74% New York Heart Association class 1 and 26% class 2). Seventy-four percentage had normal RV systolic function (RV EF >45% by CMR). No correlation was observed between Echo strain data and clinical status (EF, exercise endurance, VO₂ max, or New York Heart Association class). Cardiac magnetic resonance imaging RV global circumferential strain GCS and RV EF had moderate negative correlation (r = -0.65, P < .001). Global circumferential strain was significantly different for those with RV EF above and below 45%, while global peak longitudinal strain (GLS) was not. Patients had reduced CMR myocardial strain values compared with healthy controls.

CONCLUSIONS

Reduced RV CMR GCS (for those with RV EF <45%) suggests that CMR evaluation may enhance early detection of detrimental changes in the systemic RV myocardium.

Comparison of vector velocity imaging and three-dimensional speckle tracking echocardiography for assessment of left ventricular longitudinal strain in hypertrophic cardiomyopathy

Background: Vector velocity imaging (VVI) is a two-dimensional wall motion tracking method that can measure cardiac mechanics in hypertrophic cardiomyopathy (HCM). 3D-speckle tracking echocardiography (3D-STE) has been proven to be superior to conventional measures in assessment of LV function. The aim of this study was to compare the two technologies in the assessment of LV longitudinal strain (LS) in HCM patients. Methods: A total of 50 patients with HCM were investigated using VVI and 3D-STE in same setting. 3D-STE allows obtaining longitudinal, circumferential, radial and area strains (AS). Values of longitudinal strain (LS) and AS by 3D-STE were compared to VVI- derived analyses. Thereafter, VVI-LS values were correlated with LV phenotype. Last, the variability of VVI versus 3DE strain measurements as well as recorded time of analysis was assessed. Results: The absolute value of 3D-STE LS and AS is significantly higher than VVI-LS (P < 0.0001). VVI provided complete longitudinal LV strain information, similar to 3D-STE. There is excellent agreement between the two technologies-derived values, however, a greater number of segments could be analyzed using VVI (94.7%), compared with 3DE (62.1%). Despite VVI being more time consuming, VVI-LS is more correlated to LV mass index, mitral regurgitation severity and functional class when compared with 3D-STE LS and AS. Conclusions: VVI is a feasible modality for assessing LV longitudinal strain. Although VVI agreed well with 3D-STE for most of regional and global LS, a better correlation was found between VVI-LS and HCM phenotype. It is hypothesized that this discrepancy originates from the inferior imaging quality using 3D tracking algorithms.

Velocity vector imaging for the assessment of segmental ventricular function in children with a single right ventricle after cavopulmonary anastomosis

OBJECTIVE

Ventricular function assessment is very important for the treatment and prognostic classification of children with a single right ventricle (SRV) after cavopulmonary anastomosis (CPA). However, unusual ventricular shapes can result in inaccurate measurements. The aim of this study was to evaluate velocity vector imaging (VVI) for assessing segmental ventricular function in children with SRV after CPA.

METHODS

Twenty-one children with SRV after CPA and 21 age- and sex-matched children with normal biventricular anatomy and function were included. The longitudinal velocity, displacement, strain and strain rate were measured in the two groups in six segments by VVI. The velocity, displacement, strain and strain rate of the SRVs were compared with max(dp/dt) measured during simultaneous cardiac catheterization in the SRV subjects.

RESULTS

The control group consisted of 13 males and 8 females (69% males) with a mean age of 6.7 ± 3.5 years and mean weight of 20.5 ± 6.5 kg, and the study group consisted of 13 males and 8 females with a mean age 6.7 ± 3.7 years and mean weight of 20.6 ± 6.8 kg. Age, weight and sex distribution were similar between the groups (all, p > .05). Strain and strain rate values in all six segments were significantly lower in the study group than in the control group (all, p < .05). The max(dp/dt) of the SRV was 522.84 ± 158.32 mmHg/s, and the strain rate of the basal segment at the rudimentary chamber correlated best with max(dp/dt) (r = 0.74, p < .01).

CONCLUSIONS

Segmental ventricular dysfunction was present in children with SRV after CPA, and it could be assessed using VVI.

Immediate Postnatal Ventricular Performance Is Associated with Mortality in Hypoplastic Left Heart Syndrome

Right ventricular (RV) function as assessed by deformation has been evaluated prenatally and after palliation in hypoplastic left heart syndrome (HLHS). However, limited data exist about the immediate postnatal cardiac adaptation and RV function in HLHS. We compared echocardiographic measures of cardiac performance in HLHS versus controls in their first week of life. As a secondary objective, we evaluated if markers at the first echocardiogram were associated with mid- and long-term outcomes. Clinical and echocardiographic data of patients with HLHS between 2013 and 2016 were reviewed. The study population was matched with controls whose echocardiograms were obtained due to murmur or rule out coarctation. Speckle-tracking echocardiography was used to assess deformation. Thirty-four patients with HLHS and 28 controls were analyzed. Age at echocardiogram was similar between HLHS and controls. The RV of HLHS was compared to both RV and left ventricle (LV) of controls. HLHS deformation parameters [RV peak global longitudinal strain (GLS), global longitudinal strain rate (GLSR)] and tricuspid annular plane systolic excursion (TAPSE) were decreased compared to RV of controls. The LV-fractional area change, peak GLS, GLSR, circumferential strain, and strain rate of controls were higher than the RV of HLHS. Calculated cardiac output (CO) was higher in the HLHS group (592 vs. 183 mL/kg/min, p = 0.0001) but similar to the combined LV and RV output of controls. Later mortality or cardiac transplantation was associated with the RV CO and RV stroke distance at initial echocardiogram. Cox proportional hazard regression determined that restriction at atrial septum, decreased initial RV stroke distance and decreased TAPSE had a higher risk of death or cardiac transplantation. TAPSE and RV stroke distance by velocity time integral had adequate inter-reader variability by Bland-Altman plot and Pearson's correlation. Our study found that the HLHS RV deformation is decreased in the early postnatal period when compared to both LV and RV of controls, but deformation was not associated with mid- and long-term outcomes. Later mortality or cardiac transplantation was associated with decreased initial stroke distance and cardiac output. Early evaluation of patients with HLHS should include an assessment of stroke distance and future research should evaluate its implication in management strategies.

Growth of Cardiovascular Structures from the Fetus to the Young Adult

The size, hemodynamics, and function of cardiovascular structures change dramatically from the early fetal life to late adolescence. The principal determinants of cardiovascular dimensions are related to the blood flow needed to meet metabolic demands. This demand is in turn tightly related to body size and body composition, keeping in mind that various tissues may have different metabolic rates. There is no simple model that links cardiac dimensions with a single body size measurement. Consequently, despite abundant scientific literature, few studies have proposed pediatric reference values that efficiently and completely account for the effect of body size. Other factors influence cardiovascular size and function in children, including sex. The influence of sex is multifactorial and not fully understood, but differences in body size and body composition play an important role. We will first review the determinants of cardiovascular size and function in children. We then explore the evaluation and normalization of cardiovascular size and function in pediatric cardiology in relation to the growth of cardiovascular structures during childhood, with a particular focus on sex differences.

Recovery of myocardial mechanics in Kawasaki disease demonstrated by speckle tracking and tissue Doppler methods

AIM

To investigate myocardial deformation and function during treatment for Kawasaki disease (KD) in children.

METHODS

We performed speckle tracking echocardiography (STE) and tissue Doppler imaging (TDI) in 15 children with KD and 15 healthy children during treatment for KD. STE was performed for longitudinal and circumferential strain (S) and strain rate (SR) at the left ventricle (LV) and for longitudinal S and SR at the right ventricle (RV). TDI was performed at the base of interventricular septum (IVS), LV, and RV.

RESULTS

Among TDI parameters, E_m and ejection time (ET) at IVS, ET at LV and ET at RV obtained obtained before treatment were significantly lower in patients with KD compared to controls. After treatment, in spite of improvements, ET at IVS and ET at RV remained significantly lower in patients with KD compared to controls. Left ventricular global longitudinal and circumferential S and SR values obtained before treatment were significantly lower in patients with KD compared to controls. Left ventricular S and SR values were found to be increased after treatment. However, left ventricular global circumferential S value remained significantly lower in patients with KD compared to controls. There were no significant differences in right ventricular global longitudinal S and SR values between patients and controls before treatment.

CONCLUSION

During acute phase, patients with KD have reduced global left ventricular S and SR which may be more sensitive indicators of myocardial inflammation. This study showed gradual improvements in left ventricular myocardial function during treatment for KD.

Ventricular Performance is Associated with Need for Extracorporeal Membrane Oxygenation in Newborns with Congenital Diaphragmatic Hernia

OBJECTIVE

To compare echocardiography (ECHO) findings of patients with congenital diaphragmatic hernia (CDH) who required extracorporeal membrane oxygenation (ECMO) to non-ECMO treated patients.

STUDY DESIGN

We reviewed clinical and ECHO data of newborns with CDH born between 2009 and 2016. Exclusions included major anomalies, genetic syndromes, or no ECHO prior to ECMO. Pulmonary hypertension was assessed by ductal shunting and tricuspid regurgitant jet. Speckle tracking echocardiography (STE) assessed function by quantifying deformation.

RESULTS

Patients with CDH (15 ECMO and 29 with no ECMO) were analyzed. Most patients had a left CDH (88.6%). Age at ECHO was similar between groups. Outborn status (P = .009) and liver position (P = .009) were associated with need for ECMO. Compared with non-ECMO patients, patients who required ECMO had significantly decreased left and right ventricular function by both conventional and STE measures, as well as decreased right and left ventricular output. The right ventricular eccentricity index was higher in ECMO vs non-ECMO patients (2.2 vs 1.8, P = .02). There was no difference in pulmonary hypertension between CDH groups.

CONCLUSIONS

Need for ECMO was associated with decreased left and right ventricular function, as assessed by standard and STE measures. There was no difference in pulmonary hypertension between non ECMO and ECMO patients. Abnormal cardiac function may explain nonresponse to pulmonary vasodilators in patients with CDH. Management strategies to improve cardiac function may reduce the need for ECMO in newborns with CDH.

Pathophysiology, screening and diagnosis of pulmonary hypertension in infants with bronchopulmonary dysplasia - A review of the literature

Bronchopulmonary dysplasia (BPD) is a common complication of extreme prematurity, which has increased over the last 20 years. BPD is associated with increased morbidities and mortality. It has been increasingly recognized that BPD affects overall lung development including the pulmonary vasculature. More recent studies have demonstrated an increased awareness of pulmonary arterial hypertension (PH) in BPD patients and recent international guidelines have advocated for better screening. This review will describe the current understanding of the pathophysiology of PH in infants with BPD, the in-depth assessment of the available literature linking PH and BPD, and propose an approach of screening and diagnosis of PH in infants with BPD.

Pediatric Reference Values and Z Score Equations for Left Ventricular Systolic Strain Measured by Two-Dimensional Speckle-Tracking Echocardiography

BACKGROUND

In pediatric echocardiography, myocardial strain measurements are likely influenced by cardiac size and growth in healthy children. The application of this technique in clinical practice has been hampered by the lack of good normal reference values for the pediatric population. The aim of this study was to determine reference values and Z score equations for left ventricular systolic circumferential and longitudinal strain in a healthy pediatric population.

METHODS

Two hundred thirty-three healthy subjects 1 to 18 years of age were prospectively recruited. Left ventricular systolic longitudinal and circumferential strain measurements were recorded using two-dimensional speckle-tracking. Normalization for body size was performed using parametric nonlinear regression modeling. Several analyses were performed to detect potential residual associations with body size, residual heteroscedasticity, or departure from an adequate Z score distribution.

RESULTS

There were weak but statistically significant nonlinear associations between body size and most strain values. Body surface area was superior to adjust for body size compared with age, height, and weight. Most strain values displayed a second-order polynomial relationship with body surface area. Z score equations were computed with adequate normal distributions and without residual associations in relation to BSA for most strain parameters.

CONCLUSIONS

There was a weak but significant influence of body size on most left ventricular circumferential and longitudinal systolic strain parameters used in pediatric echocardiography. Z scores are presented for strain measurements normalized to body surface area and adjusted for heteroscedasticity. The use of these normalized values may reduce the risk for misclassification caused by normal variation in myocardial strain values during growth.

Review and status report of pediatric left ventricular systolic strain and strain rate nomograms

Interest in strain (ε) and strain rate (SR) for the assessment of pediatric left ventricular (LV) myocardial function has increased. However, the strengths and limitations of published pediatric nomograms have not been critically evaluated. A literature search was conducted accessing the National Library of Medicine using the keywords myocardial velocity, strain, strain rate, pediatric, reference values, and nomograms. Adding the following keywords, the results were further refined: neonates, infants, adolescents, range/intervals, and speckle tracking. Ten published studies evaluating myocardial velocities, ε, or SR nomograms were analyzed. Sample sizes were limited in most of these studies, particularly in terms of neonates. Heterogeneous methods-tissue Doppler imaging, two- and three-dimensional speckle tracking-were used to perform and normalize measurements. Although most studies adjusted measurements for age, classification by specific age subgroups varied. Few studies addressed the relationships of ε and SR measurements to body size and heart rate. Data have been generally expressed by mean values and standard deviations; Z scores and percentiles that are commonly employed for pediatric echocardiographic quantification have been never used. Reference values for ε and SR were found to be reproducible in older children; however, they varied significantly in neonates and infants. Pediatric nomograms for LV ε and SR are limited by (a) small sample sizes, (b) inconsistent methodology used for derivation and normalization, and (c) scarcity of neonatal data. Some of the studies demonstrate reproducible patterns for systolic deformation in older children. There is need for comprehensive nomograms of myocardial ε and SR involving a large population of normal children obtained using standardized methodology.

Cardiac axis shift within the cardiac cycle of normal fetuses and fetuses with congenital heart defect

OBJECTIVES

To investigate changes in the cardiac axis (CAx) within the cardiac cycle of normal fetuses and fetuses with congenital heart defects (CHD).

METHODS

This was a retrospective case-control study in which stored videoclips of four-chamber views from 527 prenatal ultrasound examinations performed at 18 + 0 to 36 + 6 weeks of gestation were reviewed. Among the ultrasound scans included, 287 were of normal fetuses (controls) and 240 were of fetuses with CHD. In each case, the CAx was measured at end systole (just before the atrioventricular (AV) valve opened) and at end diastole (just before the AV valve closed). CAx measurements of fetuses with CHD were compared to those of controls.

RESULTS

The mean CAx in the control group was 45.9 ± 8.5° at end systole and 38.3 ± 8.4° at end diastole (P < 0.001), resulting in an average difference of 7.6 ± 3.2°. The mean CAx in fetuses with CHD was 53.4 ± 17.8° at end systole and 47.5 ± 17.3° at end diastole (P < 0.001), resulting in an average difference of 5.9 ± 6.3°. However, in some forms of CHD, such as hypoplastic left heart syndrome and L-transposition of the great arteries, the CAx was greater at end diastole than at end systole, with a difference of more than 5°. In 21.3% of control fetuses, there was a CAx shift within the cardiac cycle of ≥ 10°. Abnormal CAx measured at end systole was strongly associated with CHD.

CONCLUSIONS

Measurement of the CAx at end systole provides values that differ from those when measured at end diastole, in both normal fetuses and those with CHD. We recommend that the CAx be measured at end systole as a greater proportion of fetuses with CHD and fewer normal fetuses have an abnormal CAx at this stage compared to at end diastole. The occurrence of an abnormal CAx and the CAx shift within the fetal cardiac cycle depend on the type of CHD.

Noninvasive Evaluation of Myocardial Systolic Dysfunction in the Early Stage of Kawasaki Disease: A Speckle-Tracking Echocardiography Study

Background:

Evaluation of myocardial function by speckle-tracking echocardiography is a new method for the early diagnosis of systolic dysfunction.

Objectives:

We aimed to determine myocardial speckle-tracking echocardiography indices in Kawasaki Disease (KD) patients and compare them with the same indices in control subjects.

Patients and Methods:

Thirty-two patients (65.5% males) with KD and 19 control subjects with normal echocardiography participated in this study. After their demographic characteristics and clinical findings were recorded, all the participants underwent transthoracic echocardiography. Strain (S), Strain Rate (SR), Time to Peak Strain (TPS), and Strain Rate (TPSR), longitudinal velocity and view point velocity images in the two, three, and four-chamber views were semi-automatically obtained via speckle-tracking echocardiography.

Results:

Among the patients, Twenty-four cases (75%) were younger than 4 years. Mean global S and SR was significantly reduced in the KD patients compared to controls (17.03 ± 1.28 vs. 20.22 ± 2.14% and 1.66 ± 0.16 vs. 1.97 ± 0.25 1/second, respectively), while there were no significant differences regarding mean TPS, TPSR, longitudinal velocity and view point velocity. Using repeated measure of analysis of variances, we observed that S and SR decreased from base to apical level in both groups. The change in the pattern of age adjusted mean S and SR across levels was significantly different between the groups (P < 0.001 for both parameters).

Conclusions:

We showed changes in S and SR assessed in KD patients versus control subjects in the acute phase of KD. However, we suggest that further studies be undertaken to compare S and SR in the acute phase and thereafter in KD patients.

Noninvasive assessment of myocardial mechanics of the left ventricle in rabbits using velocity vector imaging

BACKGROUND

Our study aimed to investigate the feasibility of velocity vector imaging (VVI) to analyze left ventricular (LV) myocardial mechanics in rabbits at basal state.

MATERIAL AND METHODS

The animals used in this study were 30 New Zealand white rabbits. All rabbits underwent routine echocardiography under VVI-mode at basal state. The 2-dimensional (2-D) echocardiography images acquired included parasternal left long-axis views and short-axis views at the level of LV mitral valve, papillary muscles, and apex. Images were analyzed by VVI software.

RESULTS

At basal state, longitudinal LV velocity decreased from the basal to the apical segment (P<0.05). In the short axis direction, the highest peak myocardial velocity was found between the anterior septum and anterior wall for each segment at the same level; the peak strains and strain rates (SR) were the highest in the anterior and lateral wall compared to other segments (all P<0.05). During systole, LV base rotated in a clockwise direction and LV apex rotated in a counter-clockwise direction, while during diastole, both LV base and apex rotated in the direction opposite to systole. The rotation angle, rotation velocity and unwinding velocity in the apical segment were greater than the basal segment (P<0.05).

CONCLUSIONS

VVI is a reliable tool for evaluating LV myocardial mechanics in rabbits at basal state, and the LV long-axis short-axis and torsional motions reflect the normal regular patterns. Our study lays the foundation for future experimental approaches in rabbit models and for other applications related to the study of human myocardial mechanics.

Right-ventricular global longitudinal strain may predict neo-aortic arch obstruction after Norwood/Sano procedure in children with hypoplastic left heart syndrome

Neo-aortic arch obstruction (NAAO) is a common complication following the Norwood/Sano procedure (NP) for hypoplastic left heart syndrome (HLHS) and is associated with increased morbidity and mortality. However, there is currently no objective method for predicting which patients will develop NAAO. This study was designed to test the hypothesis that hemodynamic changes from development of NAAO after NP in patients with HLHS will lead to changes in myocardial dynamics that could be detected before clinical symptoms develop with strain analysis using velocity vector imaging. Patients with HLHS who had at least one cardiac catheterization after NP were identified retrospectively. Strain analysis was performed on all echocardiograms preceding the first catheterization and any subsequent catheterization performed for intervention on NAAO. Twelve patients developed NAAO and 30 patients never developed NAAO. Right ventricular strain was worse in the group that developed NAAO (-6.2 vs. -8.6 %, p = 0.040) at a median of 59 days prior to diagnosis of NAAO. Those patients that developed NAAO following NP were significantly younger at the time of first catheterization than those that did not develop NAAO (92 ± 50 vs. 140 ± 36 days, p = 0.001). This study demonstrates that right ventricular GLS is abnormal in HLHS patients following NP and worsening right ventricular strain may be predictive of the future development of NAAO.

Fetal right ventricular contraction and relaxation times at 11-13 weeks' gestation on speckle tracking imaging

OBJECTIVE

To examine the contraction time and relaxation time of the right ventricle at 11-13 weeks' gestation in trisomy 21 and euploid fetuses by speckle tracking ultrasound imaging.

METHODS

Measurement of fetal nuchal translucency (NT) thickness, Doppler assessment for tricuspid regurgitation and reversed A-wave in the ductus venosus (DV) and fetal echocardiography were performed immediately before chorionic villus sampling for fetal karyotyping at 11-13 weeks' gestation. Digital videoclips of the four-chamber view of the fetal heart were recorded and analyzed offline using speckle tracking imaging software. The contraction time, which is the time between the highest and lowest peaks in the right ventricular area, and relaxation time, which is the time between the lowest and the subsequent highest area peak, were measured and expressed as a percentage of the duration of the cardiac cycle. Values in trisomy 21 and euploid fetuses were compared.

RESULTS

Mean contraction time and relaxation time in 119 euploid fetuses were 52.1% (95% CI, 51.6-52.8%) and 47.8% (95% CI, 47.2-48.4%), respectively. In 21 trisomy 21 fetuses, mean contraction time was significantly higher (57.0% (95% CI, 55.2-58.9%); P<0.01) and relaxation time lower (42.9% (95% CI, 41.1-44.8%); P<0.01) than in euploid fetuses. Multiple regression analysis showed that significant contributions to contraction time and relaxation time were provided by fetal karyotype, NT and tricuspid regurgitation, but not by reversed A-wave in the DV or the presence of a cardiac defect.

CONCLUSION

In first-trimester fetuses with trisomy 21 and in euploid fetuses with increased NT and tricuspid regurgitation there is evidence of increased right ventricular contraction time and shortening of the relaxation time.

Echocardiography in pediatric pulmonary hypertension

Pulmonary hypertension (PH) can be a rapidly progressive and fatal disease. Although right heart catheterization remains the gold standard in evaluation of PH, echocardiography remains an important tool in screening, diagnosing, evaluating, and following these patients. In this article, we will review the important echocardiographic parameters of the right heart in evaluating its anatomy, hemodynamic assessment, systolic, and diastolic function in children with PH.

Does accessory pathway significantly alter left ventricular twist/torsion? A study in Wolff-Parkinson-White syndrome by velocity vector imaging

BACKGROUND

The aim of this study was to determine the impact of manifest accessory pathway on left ventricle (LV) twist physiology in Wolff-Parkinson-White (WPW) patients. Although this issue was addressed in 1 study based on speckle tracking method, there was no comparative study with a different technique. We planned to use velocity vector imaging (VVI) to find out how much an accessory pathway can affect LV twist mechanics.

METHODS

Thirty patients were enrolled regarding inclusion and exclusion criteria. Two serial comprehensive transthoracic echocardiography evaluations were performed before and after radiofrequency catheter ablation (RFCA) within 24 hours. Stored cine loops were analyzed using VVI technique and LV twist and related parameters were extracted.

RESULTS

Comparing pre- and post-RFCA data, no significant changes were observed in LV systolic and diastolic dimensions, LV ejection fraction (LVEF), and Doppler and tissue Doppler-related parameters. VVI study revealed remarkable rise in peak LV apical rotation (10.3º ± 3.0º to 13.8º ± 3.6º, P < 0.001) and basal rotation (-6.0 ± 1.8º to -7.7 ± 1.8º, P < 0.001) after RFCA. Subsequently LV twist showed a surge from 14.7º ± 3.9º to 20.2º ± 4.4º (P < 0.001). LV untwisting rate changed significantly from -96 ± 67 to -149.0 ± 47.5°/sec (P < 0.001) and apical-basal rotation delay showed a remarkable decline after RFCA (106 ± 81 vs. 42.8 ± 26.0 msec, P < 0.001).

CONCLUSION

Accessory pathways have a major impact on LV twist mechanics.

Comparison of the right and left ventricular performance during the fetal development using velocity vector imaging

BACKGROUND

Studies on myocardial characteristics examined by speckle-tracking echocardiography are limited.

AIMS

To compare myocardial performance between the right and left ventricles during the fetal development using velocity vector imaging (VVI).

SUBJECTS AND STUDY DESIGN

Echocardiograms of 95 uncomplicated singleton fetuses (19-36 weeks pregnancy) were retrospectively analyzed by VVI to measure global longitudinal peak velocity, strain, and strain rate of both the right ventricle (RV) and left ventricle (LV). The regional values were calculated for three segments (base, mid, and apex) of the ventricular free wall and segment.

OUTCOME MEASURES

The VVI-derived measurements were examined for gestational age and compared between ventricles.

RESULTS

The global peak systolic and diastolic velocity values of both ventricles significantly increased over gestation examined, whereas the global systolic strain and strain rate were stable (RV: strain -22.6 ± 5.0%, strain rate -2.6 ± 0.7/s; LV: strain -21.5 ± 5.6%, strain rate -2.5 ± 0.7/s). Compared to the LV, the RV showed significantly higher global velocity in systole and diastole (P = 0.001 for systole, P < 0.001 for diastole). The global systolic velocity of the LV increased close to the RV toward term, whereas the RV was dominant in diastole throughout the examined gestation. Basal strain and strain rate in the RV were significantly greater than that of the LV, although there were no significant differences in the middle and apical values between ventricles.

CONCLUSION

Our findings suggest the RV predominance of longitudinal contraction and dilatation, compared to the LV in uncomplicated fetuses.

Myocardial strain and strain rate in Kawasaki disease

AIMS

We sought to determine whether velocity vector imaging (VVI)-derived left ventricular (LV) myocardial deformation indices could detect subtle myocardial abnormalities in acute Kawasaki disease (KD).

METHODS AND RESULTS

The study cohort of children with KD was divided by coronary artery dilation (CAD, Z-score >2.5) and/or uncomplicated vs. treatment-resistant (persistent/recrudescent fever) cases and compared with age-matched controls. Peak systolic LV myocardial strain (ε) and strain rate (SR) were obtained using VVI on pre-treatment echocardiograms. Comparisons were made between controls and (i) the entire KD group, (ii) KD group subdivided by CAD, and (iii) KD group subdivided by treatment resistance. The KD group consisted of 32 children (66% male, 24 ± 20 months). Of these, 17 had CAD and 14 had resistant KD. The control group consisted of 22 children (55% male, 20 ± 17 months). Routine echo indices of LV systolic function were normal for both groups. Compared with controls, KD patients had lower global longitudinal ε (-15.29 vs. -12.94, P = 0.04) and SR (-1.12 vs. -0.87, P = 0.003). On subgroup analysis compared with controls, KD patients with CAD (n = 17) had lower longitudinal ε (-15.29 vs. -11.87, P = 0.02) and SR (-1.12 vs. -0.86, P = 0.005). Subdivided by treatment resistance, compared with controls, those with resistant KD had lower longitudinal ε (-15.29 vs. -11.8, P = 0.01) and SR (-1.12 vs. -0.82, P = 0.003).

CONCLUSION

Despite normal LV systolic function by routine echocardiographic measurements, KD patients have reduced longitudinal LV ε and SR, which may be more sensitive indicators of myocardial inflammation and may provide supportive criteria to avoid delayed diagnosis of KD.

Pulmonary artery pressure and cardiac function in children and adolescents after rapid ascent to 3,450 m

High-altitude destinations are visited by increasing numbers of children and adolescents. High-altitude hypoxia triggers pulmonary hypertension that in turn may have adverse effects on cardiac function and may induce life-threatening high-altitude pulmonary edema (HAPE), but there are limited data in this young population. We, therefore, assessed in 118 nonacclimatized healthy children and adolescents (mean ± SD; age: 11 ± 2 yr) the effects of rapid ascent to high altitude on pulmonary artery pressure and right and left ventricular function by echocardiography. Pulmonary artery pressure was estimated by measuring the systolic right ventricular to right atrial pressure gradient. The echocardiography was performed at low altitude and 40 h after rapid ascent to 3,450 m. Pulmonary artery pressure was more than twofold higher at high than at low altitude (35 ± 11 vs. 16 ± 3 mmHg; P < 0.0001), and there existed a wide variability of pulmonary artery pressure at high altitude with an estimated upper 95% limit of 52 mmHg. Moreover, pulmonary artery pressure and its altitude-induced increase were inversely related to age, resulting in an almost twofold larger increase in the 6- to 9- than in the 14- to 16-yr-old participants (24 ± 12 vs. 13 ± 8 mmHg; P = 0.004). Even in children with the most severe altitude-induced pulmonary hypertension, right ventricular systolic function did not decrease, but increased, and none of the children developed HAPE. HAPE appears to be a rare event in this young population after rapid ascent to this altitude at which major tourist destinations are located.

Comparison of global and regional right and left ventricular longitudinal peak systolic strain, strain rate and velocity in healthy fetuses using a novel feature tracking technique

AIMS

To compare the feature tracking derived measurements of the right (RV) and left ventricular (LV) myocardium in healthy fetuses and evaluate the correlation with advancing pregnancy.

METHODS

Global and segmental longitudinal peak systolic strain, strain rate and velocity of the RV and LV myocardium were assessed with feature tracking technique in 150 healthy fetuses (13-39, median 22 weeks).

RESULTS

RV global and free wall strain and strain rate values were significantly higher than those in the LV segments (P<0.001 and P<0.001). In all segments on both ventricles longitudinal peak systolic velocity measurements exhibited a significant base to apex gradient (P<0.001) and increased with advancing pregnancy (P<0.001). LV global strain and strain rate values remained constant throughout gestation, whereas RV measurements decreased (P<0.05). With advancing pregnancy the difference between RV and LV global longitudinal velocity increased significantly, whereas the difference of strain and strain rate decreased significantly.

CONCLUSION

RV deformation parameters and velocity values are significantly higher compared to LV values. LV deformation parameters are stable throughout gestation, whereas RV measurements decrease significantly. The difference between global RV and LV myocardial values were significant throughout gestation, velocity values increased, whereas deformation parameters decreased.

Two-dimensional speckle strain and dyssynchrony in single left ventricles vs. normal left ventricles

BACKGROUND

Patients with single left ventricle (LV) physiology maybe at increased risk for myocardial dysfunction and mechanical dyssynchrony. Newer echocardiographic modalities may be able to better quantitate LV function in this unique population. Our objective was to use 2D-speckle analysis of strain and strain rate to quantify systolic function and dyssynchrony in single LV post-Fontan patients and compare them to control LV patients.

METHODS

Patients with single LV status post-Fontan procedure and patients with normal biventricular anatomy were studied. Two-dimensional speckle echocardiography was used to measure strain, strain rate, time to peak, and longitudinal displacement in a six-segment model of the LV. Independent t-tests were used to compare group means.

RESULTS

Twelve patients with single LV physiology and thirteen control patients were studied. There was no significant difference in ages for the single LV patients vs. control patients (7.1 + 2.8 years vs. 5.7 + 1.8 years). Single LV strain values were significantly lower in four of the six segments compared with control LV (mid interventricular septal [IVS]: -19.3 + 6.4% vs. -23.8 + 3.5%, apical IVS: -20.8 + 5.4% vs. -27.4 + 4.7%, basal LV: -20.6 + 6.6% vs. -25.8 + 3.4%, and apical LV: -21.0 + 6.2% vs. -26.1 + 4.3%). Longitudinal displacement was lower for all three segments of the IVS for the single LV vs. control LV. Modified Yu index for strain and strain rate time to peak was longer in the single LV patients vs. controls (51.2 + 18.2 ms vs. 27.9 + 8.0 ms and 90.2 + 24.2 ms vs. 52.5 + 23.7 ms, respectively).

CONCLUSION

Significant differences in strain analysis between single LV patients vs. control patients with normal biventricular physiology exist at a relatively young age. Future studies are needed to determine the significance of these differences.

Temporal and spatial performance of vector velocity imaging in the human fetal heart

OBJECTIVES

To assess the spatial and temporal performance of fetal myocardial speckle tracking, using high-frame-rate (HFR) storing and Lagrangian strain analysis.

METHODS

Dummy electrocardiographic signaling permitted DICOM HFR in 124 normal fetuses and paired low-frame-rate (LFR) video storing at 25 Hz in 93 of them. Vector velocity imaging (VVI) tracking co-ordinates were used to compare time and spatial domain measures. We compared tracking success, Lagrangian strain, peak diastolic velocity and positive strain rate values in HFR vs. LFR video storing. Further comparisons within an HFR subset included Lagrangian vs. natural strain, VVI vs. M-mode annular displacement, and VVI vs. pulsed-wave tissue Doppler imaging (TDI) peak velocities.

RESULTS

HFR (average 79.4 Hz) tracking was more successful than LFR (86 vs. 76%, P = 0.024). Lagrangian and natural HFR strain correlated highly (left ventricle (LV): r = 0.883, P < 0.001; right ventricle (RV): r = 0.792, P < 0.001) but natural strain gave 20% lower values, suggesting reduced reliability of measurement. Lagrangian HFR strain was similar in LV and RV and decreased with gestation (P = 0.015 and P < 0.001, respectively). LV Lagrangian LFR strain was significantly lower than the values for the RV (P < 0.001) and those using paired LV-HFR recordings (P = 0.007). Annular displacement methods correlated highly (LV = 1.046, r = 0.90, P < 0.001; RV = 1.170, r = 0.88, P < 0.001). Early diastolic waves were visible in 95% of TDI, but in only 26% of HFR and 0% of LFR recordings, and HFR-VVI velocities were significantly lower than those for TDI (P < 0.001).

CONCLUSIONS

Doppler estimation of velocities remains superior to VVI but image gating and use of original co-ordinates should improve offline VVI assessment of fetal myocardial function.

Assessment of right ventricular global and regional longitudinal peak systolic strain, strain rate and velocity in healthy fetuses and impact of gestational age using a novel speckle/feature-tracking based algorithm

OBJECTIVE

To evaluate the correlation between feature tracking-derived measurements of the right ventricular myocardium and gestational age in healthy fetuses.

METHODS

Global and segmental longitudinal peak systolic strain, strain rate and velocity values of the right ventricular myocardium were assessed by a novel feature-tracking technique in 150 healthy fetuses at between 13 and 39 weeks' gestation. Reference ranges were constructed with respect to gestational age, and inter- and intraobserver variability was analyzed.

RESULTS

Strain, strain rate and velocity exhibited a segmental base to apex gradient (P < 0.001). Global longitudinal peak systolic velocities increased significantly across the gestational age range considered (P < 0.001), whereas global longitudinal peak systolic strain and strain rate (taken as absolute values) decreased significantly (P < 0.001 and P < 0.001). Inter- and intraobserver variability of global right ventricular peak systolic strain, strain rate and velocity was acceptable. The SDs of measurement error between the two observers were 5.9%, 0.7/s and 0.5 cm/s, respectively.

CONCLUSIONS

Global myocardial peak systolic velocities of the right ventricle increase with gestational age whereas global myocardial peak absolute systolic strain and strain rate significantly decrease throughout gestation. This novel angle-independent technique offers a new non-invasive approach for quantifying and monitoring fetal myocardial function throughout gestation.

Measurement of right ventricular mechanical synchrony in children using tissue Doppler velocity and two-dimensional strain imaging

BACKGROUND

Right ventricular (RV) mechanical dyssynchrony may be associated with RV dysfunction. The aim of this study was to investigate the feasibility of measuring RV synchrony in normal children using Doppler tissue imaging and two-dimensional speckle tracking.

METHODS

The RV delay (difference in time to peak velocity or two-dimensional strain between the RV lateral wall and the interventricular septum) and standard deviation of time to peak velocity or strain were measured and corrected for heart rate. Intraobserver and interobserver reliabilities were analyzed.

RESULTS

One hundred three children were studied. RV delay analysis was feasible in 95% by Doppler tissue imaging and in 63% by two-dimensional speckle tracking (99% and 84% when imaging was adequate). The mean ± 2 standard deviations RV delay by either method was <70 msec or <8% of the cardiac cycle in systole and <65 msec or <7% of the cardiac cycle in diastole. Intraobserver and interobserver variability showed small absolute differences but high variability because delays were either positive or negative.

CONCLUSION

This study establishes the feasibility of the measurement of RV mechanical synchrony in normal children aged 3 to 18 years.

Two-dimensional speckle strain and dyssynchrony in single right ventricles versus normal right ventricles

BACKGROUND

Patients with single-right ventricle (RV) physiology are at increased risk for myocardial dysfunction and mechanical dyssynchrony. Newer echocardiographic modalities may be better able to quantitate right ventricular function in this unique population. The aim of this study was to use two-dimensional speckle analysis of strain and strain rate to quantify systolic function and dyssynchrony in single-RV post-Fontan patients and compare them with values for controls.

METHODS

Patients with single RV who underwent Fontan palliation and patients with normal biventricular anatomy were studied. Two-dimensional speckle echocardiography was used to measure strain, strain rate, time to peak, and longitudinal displacement in a 6-segment model of the RV. Independent t tests were used to compare group means. P values < .05 were considered significant.

RESULTS

Thirteen patients were studied in each group. There was no significant difference in age between single-RV patients and controls (6.60 +/- 2.07 vs 5.75 +/- 1.83 years, respectively). Single-RV strain values were significantly lower in all 6 segments compared with values in controls (basal interventricular septum [IVS], -14.28 +/- 7.78% vs -22.00 +/- 2.36%; mid IVS, -17.70 +/- 4.54% vs -22.99 +/- 2.71%; apical IVS, -19.46 +/- 4.97% vs -25.42 +/- 4.06%; basal RV, -22.40 +/- 5.7% vs -41.42 +/- 5.42%; mid RV, -21.20 +/- 3.21% vs -39.67 +/- 6.04%; apical RV, -20.70 +/- 4.90% vs -33.68 +/- 3.90%). Systolic strain rate and longitudinal displacement were also lower in the free wall and apical IVS in single-RV patients compared with controls. The modified Yu index for strain time to peak was longer in the single-RV patients (43.16 +/- 13.63 vs 21.72 +/- 7.25 ms).

CONCLUSION

Significant differences in strain analysis between single-RV patients and patients with biventricular physiology exist at a relatively young age. Future studies are needed to determine the clinical significance of these differences.

Do we have two hearts? New insights in right ventricular function supported by myocardial imaging echocardiography

RV performance is difficult to evaluate, given its geometry, interrelationship with the left ventricle, and sensitivity to alterations in pulmonary pressure. This article focuses on some of the challenges related to the assessment of RV function in the setting of the RV's unique anatomic, physiologic, conventional and newer echocardiographic aspects, and therapeutic implications. The majority of proposed methods of echocardiographic assessment of RV function are based on volumetric approximations of the RV. Such approaches have inherent limitations, first as volume-related measures such as EF are load dependent, second because of the complex geometry of the RV. The issue of RV geometry is usually overcome using geometry-independent parameters such as tricuspid annular excursion and the Tei index. The recent introduction of real-time three-dimensional echocardiography and myocardial imaging echocardiography (tissue Doppler imaging, 1D-strain and 2D-strain echocardiography) implied a great progress in echocardiography. Tissue Doppler imaging allows the quantitative assessment of RV systolic and diastolic function by means of measurement of myocardial velocities. Strain measurements have been shown to correlate well with sonomicrometry segment length measurements both in the inflow and outflow tract of the RV and under different loading conditions. Other findings have been reported in chronic and acute clinical settings. Standard and novel echocardiographic methods of assessment of RV size and performance can help clinicians in the treatment of acute and chronic RV failure and contribute to a better understanding of the peculiar chamber-related functional mechanisms in the context of ventricular interdependent independency.

Quantification of left ventricular twisting mechanics by velocity vector imaging in an animal model of pericardial adhesions

Diagnosis of constrictive pericarditis remains clinically challenging. Untwisting of the left ventricle (LV) is essential for normal LV diastolic function. Echocardiography is able to measure LV twisting mechanics. We designed an animal model of constrictive pericarditis to determine how pericardial-epicardial adhesions impair LV twisting mechanics. In eight open-chest pigs, the heart was exposed while preserving the pericardium. We simulated early constrictive pericarditis by pericardial constriction and patchy adhesions induced with instant glue and pericardial-epicardial stitches. Using Velocity Vector Imaging (VVI), LV magnitudes of twisting and untwisting were measured along with hemodynamic data at baseline and after the experimental intervention. Significant decreases in end-diastolic volume, ejection fraction, stroke volume, and late diastolic filling velocity reflected the effects of the pericardial adhesions. Magnitude of LV untwisting rate decreased from -80+/-23 degrees /s to -26+/-10 degrees /s (p=0.0009). LV twisting rate dropped from 78+/-20 degrees /s to 40+/-8 degrees /s (p=0.0039) and LV twist magnitude decreased from 9+/-2 degrees to 5+/-2 degrees (p=0.0081). Patchy pericardial adhesions are associated with reductions in LV untwisting rate and twisting magnitude, consistent with a negative impact of constrictive pericarditis on systolic and diastolic function. Impairments in LV twisting mechanics may have a diagnostic role in the detection of early stages of constrictive pericarditis.

Advances in echocardiography

PURPOSE OF REVIEW

This study will outline recent advances in echocardiography and their impact in the understanding of cardiac morphology and ventricular function.

RECENT FINDINGS

Evaluation of morphologic abnormalities in pediatric cardiology has benefited greatly from three-dimensional echocardiography, particularly with the introduction of high-frequency transducers. The size of cardiovascular structures is frequently affected by heart disease, and a systematic approach to adjust measurements for the effects of body size and age has helped to distinguish a normal structure from an abnormal one. Quantification of diastolic and systolic function continues to be a major focus in echocardiography. New modalities such as tissue Doppler imaging and speckle tracking echocardiography have provided new parameters to assess myocardial performance, and these parameters include myocardial velocities, ventricular twist and torsion, strain and strain rate, and mechanical dyssynchrony. Mechanical dyssynchrony analysis has been particularly useful in cardiac resynchronization therapy, a novel treatment for heart failure which shows great promise.

SUMMARY

Improved delineation of cardiac morphology has greatly augmented the current understanding of congenital heart diseases, and management strategies have been modified based on three-dimensional echocardiographic findings. The introduction of new parameters to evaluate ventricular function has provided early markers for cardiovascular impairment in several disease states, thereby allowing clinicians to monitor these patients more closely.

The gold standard for noninvasive imaging in congenital heart disease: echocardiography

PURPOSE OF REVIEW

Echocardiography in pediatric and congenital heart disease is a key diagnostic technique in patients with congenital heart disease. Due to new technological developments, it has become a rapidly evolving field.

RECENT FINDINGS

In this review, we focus on recent developments in standardization and validation of standard techniques in pediatric and congenital echocardiography. This is mainly related to standardization of image acquisition and normalization of measurements for body size. The rest of the review is focused on the application of three-dimensional echocardiography, tissue Doppler imaging and Speqle tracking techniques to pediatric heart disease.

SUMMARY

New developments in standardization of echocardiography, the introduction of three-dimensional echocardiography and new functional techniques such as tissue Doppler and Speqle tracking strengthen the position of pediatric echocardiography as the most important diagnostic tool for patients with congenital heart disease.

[Update on pediatric cardiology and congenital heart disease]

The fields of pediatric cardiology and congenital heart disease have experienced considerable progress in the last few years, with advances in new diagnostic and therapeutic techniques that can be applied at all stages of life from the fetus to the adult. This article reviews scientific publications in a number of areas that appeared between August 2007 and September 2008. In developed countries, congenital heart disease is becoming increasingly prevalent in nonpediatric patients, including pregnant women. Actions aimed at preventing coronary heart disease must be started early in infancy and should involve the promotion of a healthy diet and lifestyle. Recent developments in echocardiography include the introduction of three-dimensional echocardiography and of new techniques such as two-dimensional speckle tracking imaging, which can be used for both anatomical and functional investigations in patients with complex heart disease, including a univentricular heart. Progress has also occurred in fetal cardiology, with new data on prognosis and prognostic factors and developments in intrauterine interventions, though indications for these interventions have still to be established. Heart transplantation has become a routine procedure, supplemented in some cases by circulatory support devices. In catheter interventions, new devices have become available for the closure of atrial or ventricular septal defects and patent ductus arteriosus as well as for percutaneous pulmonary valve implantation. Surgery is also advancing, in some cases with hybrid techniques, particularly for the treatment of hypoplastic left heart syndrome. The article ends with a review of publications on cardiomyopathy, myocarditis and the treatment of bacterial endocarditis.

[Update on cardiac imaging techniques: echocardiography, cardiac magnetic resonance, and multidetector computed tomography]

This article contains a review of the most important publications on cardiac imaging that have appeared during 2008. During the year, we assisted with the clinical implementation of three-dimensional real-time transesophageal echocardiography, with the use of echocardiography for selecting patients for and monitoring those who underwent percutaneous aortic valve replacement (the majority of centers performing the technique were still in the learning phase), and with the emergence in the clinic of techniques for studying myocardial deformation. Also reviewed are the most significant developments in the application of echocardiography to coronary heart disease and cardiac resynchronization therapy and in 2 other techniques whose use is constantly increasing: cardiac magnetic resonance and multidetector cardiac computed tomography. The review ends with a description of the current state of the art in contrast echocardiography, with particular emphasis on safety in the context of recommendations made by the US Food and Drug Administration at the end of 2007.

A new 2D-based method for myocardial velocity strain and strain rate quantification in a normal adult and paediatric population: assessment of reference values

BACKGROUND

Recent advances in technology have provided the opportunity for off-line analysis of digital video-clips of two-dimensional (2-D) echocardiographic images. Commercially available software that follows the motion of cardiac structures during cardiac cycle computes both regional and global velocity, strain, and strain rate (SR). The present study aims to evaluate the clinical applicability of the software based on the tracking algorithm feature (studied for cardiology purposes) and to derive the reference values for longitudinal and circumferential strain and SR of the left ventricle in a normal population of children and young adults.

METHODS

45 healthy volunteers (30 adults: 19 male, 11 female, mean age 37 +/- 6 years; 15 children: 8 male, 7 female, mean age 8 +/- 2 years) underwent transthoracic echocardiographic examination; 2D cine-loops recordings of apical 4-four 4-chamber (4C) and 2-chamber (2C) views and short axis views were stored for off-line analysis. Computer analyses were performed using specific software relying on the algorithm of optical flow analysis, specifically designed to track the endocardial border, installed on a Windows based computer workstation. Inter and intra-observer variability was assessed.

RESULTS

The feasibility of measurements obtained with tissue tracking system was higher in apical view (100% for systolic events; 64% for diastolic events) than in short axis view (70% for systolic events; 52% for diastolic events). Longitudinal systolic velocity decreased from base to apex in all subjects (5.22 +/- 1.01 vs. 1.20 +/- 0.88; p < 0.0001). Longitudinal strain and SR significantly increased from base to apex in all subjects (-12.95 +/- 6.79 vs. -14.87 +/- 6.78; p = 0.002; -0.72 +/- 0.39 vs. -0.94 +/- 0.48, p = 0.0001, respectively). Similarly, circumferential strain and SR increased from base to apex (-21.32 +/- 5.15 vs. -27.02 +/- 5.88, p = 0.002; -1.51 +/- 0.37 vs. -1.95 +/- 0.57, p = 0.003, respectively). Values of global systolic SR, both longitudinal and circumferential, were significantly higher in children than in adults (-1.3 +/- 0.2, vs. -1.11 +/- 0.2, p = 0.006; -1.9 +/- 0.6 vs. -1.6 +/- 0.5, p = 0.0265, respectively). No significant differences in longitudinal and circumferential systolic velocities were identified for any segment when comparing adults with children.

CONCLUSION

This 2D based tissue tracking system used for computation is reliable and applicable in adults and children particularly for systolic events. Measured with this technology, we have established reference values for myocardial velocity, Strain and SR for both young adults and children.