A comparison between Philips and Tomtec for left ventricular deformation and volume measurements in neonatal intensive care patients

Fetal Left Ventricle Function Evaluated by Two-Dimensional Speckle-Tracking Echocardiography across Clinical Stages of Severity in Growth-Restricted Fetuses

Fetal growth restriction (FGR) can result in adverse perinatal outcomes due to cardiac dysfunction. This study used 2D speckle-tracking echocardiography to assess left ventricle (LV) longitudinal strain across FGR severity stages. A prospective longitudinal cohort study measured global (GLS) and segmental LV longitudinal strain in FGR fetuses, with evaluations conducted at various time points. FGR was classified into subtypes based on published criteria using fetal weight centile and Doppler parameters. A linear mixed model was employed to analyze repeated measures and compare Z-score measurements between groups throughout gestational age. The study included 40 FGR fetuses and a total of 107 evaluations were performed: 21 from small for gestational age (SGA), 74 from the FGR stage I, and 12 from the FGR stage ≥ II. The results indicate that SGA and stage I FGR fetuses exhibit higher LV GLS than stages ≥ II. Throughout gestation, SGA and FGR stage I fetuses showed similar behavior with consistently better LV GLS values when compared to FGR stages ≥ II. No significant differences were observed in LV GLS strain behavior between SGA and FGR stage I. In conclusion, all FGRs show signs of early cardiac dysfunction, with severe cases demonstrating significantly a lower LV GLS when compared to mild cases, suggesting deterioration of cardiac dysfunction with progression of fetal compromise.

Longitudinal Behavior of Left-Ventricular Strain in Fetal Growth Restriction

Fetal growth restriction (FGR) is associated with an increased risk of adverse outcomes resulting from adaptive cardiovascular changes in conditions of placental insufficiency, leading to cardiac deformation and dysfunction, which can be evaluated with 2D speckle tracking echocardiography (2D-STE). The aim of the present study was to evaluate whether reduced fetal growth is associated with cardiac left-ventricle (LV) dysfunction, using 2D-STE software widely used in postnatal echocardiography. A prospective longitudinal cohort study was performed, and global (GLO) and segmental LV longitudinal strain was measured offline and compared between FGR and appropriate-for-gestational-age (AGA) fetuses throughout gestation. All cases of FGR fetuses were paired 1:2 to AGA fetuses, and linear mixed model analysis was performed to compare behavior differences between groups throughout pregnancy. Our study shows LV fetal longitudinal strain in FGR and AGA fetuses differed upon diagnosis and behaved differently throughout gestation. FGR fetuses had lower LV strain values, both global and segmental, in comparison to AGA, suggesting subclinical cardiac dysfunction. Our study provides more data regarding fetal cardiac function in cases of placental dysfunction, as well as highlights the potential use of 2D-STE in the follow-up of cardiac function in these fetuses.

Left ventricular ejection fraction using manual and semi-automated biplane method of discs in very preterm infants

BACKGROUND

Biplane left ventricular ejection fraction (LVEF) is a valuable echocardiographic parameter for assessment of LV systolic pump efficiency in adults and children, but not often reported in preterm infants. The primary aim of this study was to longitudinally measure biplane LVEF in very preterm infants during the neonatal intensive care period. Secondary aim was to compare manual and semi-automatic determination of LVEF for agreement and variability.

METHODS

Stable preterm infants less than 30 weeks gestation were scanned on day 3, day 28, and at 36 weeks postmenstrual age. The LV endocardium was traced manually and semi-automatically using integrated speckle tracking software in apical 4-chamber and apical 3-chamber images to obtain end-diastolic volume and end-systolic volume, and calculate LVEF. Agreement between methods and variability within and between observers was determined using an interclass correlation coefficient (ICC) and Bland-Altman analysis.

RESULTS

Sixty-six preterm infants with a mean birth weight of 1100 (239) g were analyzed. The average manual biplane LVEF was 58 (3)%, 59 (3)%, and 55 (4)% at the three respective time points. Manual LVEF showed good agreement with semi-automatic LVEF (ICC 0.76) with a small bias of -1.5 (3.0)%. Interobserver variability of LVEF improved with semi-automatic tracing of the LV endocardial border (ICC manual 0.68 vs semi-automatic 0.80).

CONCLUSION

Left ventricular systolic pump efficiency in preterm infants remains stable during the neonatal intensive care period. Semi-automatic biplane LVEF has less interobserver variability and can be used interchangeably with manual biplane LVEF.

Speckle tracking echocardiographically-based analysis of ventricular strain in children: an intervendor comparison

BACKGROUND

Strain and synchrony can be calculated from a variety of software packages, but there is a paucity of data with inter-vendor comparisons in children. To test the hypothesis that different packages may affect results, independent of acquisition, we compared values obtained using two commercially available analysis tool (QLAB and TomTec), with several different settings.

METHODS

The study population included 108 children; patients were divided into three groups: (1) normal cardiac structure and conduction; (2) ventricular paced rhythm; and (3) flattened ventricular septum (reflecting right ventricular pressure or volume load lesions). We analyzed the same image acquired from the apical 4-chamber (AP4) and short-axis at the mid-papillary level (SAXM) views in both QLAB (versions 10.5 and 10.8) and TomTec (version 1.2). In QLAB version 10.8, low, medium, and high quantification smoothness settings were employed. In TomTec, images were analyzed with both low and high frame rates. Tracking quality for each package was graded. AP4 and SAXM strain and synchrony values were recorded. A mixed-effects linear regression model was used, with main effect considered significant if the p-value was < 0.05.

RESULTS

Tracking scores were high for all packages except QLAB 10.5 in the SAXM view. AP4 and SAXM strain values varied significantly between QLAB 10.5 and the other packages. Synchrony values varied widely for all strain values (p < 0.001 for both) in all packages. Quantification smoothness changes in QLAB 10.8 did not impact strain significantly in any patient group; temporal resolution changes in TomTec resulted in strain differences in children with flat ventricular septums, but not those with normal or ventricular paced hearts.

CONCLUSION

Synchrony values varied substantially among all packages in children. Strain values varied widely between QLAB 10.5 and all other software packages, recommending avoidance of QLAB 10.5 for future studies. Quantification smoothness settings in QLAB 10.8 resulted in minimal strain differences. In TomTec, low and high frame rate strain values differed only in a subset of patients (flattened septum). These data suggest that reliable comparisons between strain values derived from QLAB and TomTec is possible in certain cases, but that caution should be used especially in different hemodynamics conditions.

Comparison of strain and dyssynchrony measurements in fetal two-dimensional speckle tracking echocardiography using Philips and TomTec

Background The aim of this study was to compare Philips and TomTec two-dimensional speckle tracking echocardiography (2D-STE) software measurements of strain and dyssynchrony values in healthy fetuses. Methods This was an explorative observational study in which the echocardiographic data of 93 healthy fetuses between the 20th and 38th week of gestation were determined from a four-chamber view using 2D speckle tracking. The global and segmental longitudinal strain values of both ventricles, inter-ventricular and left intra-ventricular dyssynchrony were analyzed using QLab version 10.8 (Philips Medical Systems, Andover, MA, USA) and TomTec-Arena version 2.30 (TomTec, Unterschleißheim, Germany). Results TomTec showed persistently lower values for all of the assessed strain and dyssynchrony variables. For all variables, the bias between vendors tended to increase with gestational age, though not to a significant extent. Left ventricular dyssynchrony and longitudinal strain within the mid segment of the septum correlated best between vendors; however, the limits of agreement were wide in both cases. None of the variables assessed in the two-chamber view compared well between QLAB and TomTec. Conclusion Speckle tracking software cannot be used interchangeably between vendors. Further investigations are necessary to standardize fetal 2D-STE.

Left Ventricular Strain and Strain Rate during Submaximal Semisupine Bicycle Exercise Stress Echocardiography in Healthy Adolescents and Young Adults: Systematic Protocol and Reference Values

OBJECTIVE

Combining stress echocardiography with strain analysis is a promising approach for early detection of subclinical cardiac dysfunction not apparent at rest. Data on normal myocardial strain and strain rate (SR) response to exercise in adolescents and young adults are contradictory and limited. The aim of this study was to propose a standardized protocol for semisupine bicycle stress echocardiography and to provide corresponding reference values of left ventricular (LV) two-dimensional speckle-tracking echocardiography (2D STE) strain and SR in adolescents and young adults.

METHODS

Fifty healthy adolescents and young adults (mean age, 17.8 ± 3.2 years, 44% female) were prospectively assessed. Images were acquired at rest, low stress, submaximal stress, and during recovery. Optimal image quality for offline strain analysis was pursued, and image quality was rated. Global longitudinal strain and SR from apical four-/two-/three-chamber views and short-axis circumferential strain and SR were analyzed using vendor-independent software. Interobserver variability was assessed.

RESULTS

Strain and SR increased during progressive exercise stress. Mean LV global longitudinal strain was -20.4% ± 1.3%, SR -1.1 ± 0.15/sec at rest (heart rate, 79.4 ± 12.0 beats/minute), increasing to -22.6% ± 1.6% and -1.5 ± 0.16/sec at low stress level (heart rate, 117.1 ± 8.7 beats/minute) and -23.7% ± 1.1% and -1.9 ± 0.29/sec at submaximal stress level (heart rate, 154.2 ± 7.0 beats/minute), respectively, returning to -20.6% ± 1.4% and -1.2 ± 0.16/sec postexercise (heart rate, 90.1 ± 9.4 beats/minute). Restriction on submaximal stress level ensured adequate image quality for 2D STE strain analysis. Interobserver variability for strain was acceptable even during submaximal stress.

CONCLUSIONS

This study provides a systematic, standardized protocol and corresponding reference data for 2D LV STE-derived strain and SR during semisupine bicycle exercise testing in adolescents and young adults. According to our results, global longitudinal strain and SR appear to be the most comprehensible parameters for cross-sectional studies.

What is Left Ventricular Strain in Healthy Neonates? A Systematic Review and Meta-analysis

Reference values for left ventricular systolic strain in healthy neonates are necessary for clinical application of strain. The objectives of this systematic review were to identify echocardiographic studies that presented left ventricular strain values in healthy neonates, perform a meta-analysis for speckle tracking-derived global longitudinal strain, and identify areas that require further investigation. A structured search was applied to MEDLINE, Embase, and Cochrane Central Register of Clinical Trials in search of echocardiographic studies that presented left ventricular strain in healthy neonates. 244 studies were identified, of which 16 studies including speckle tracking and tissue Doppler strain in the longitudinal, radial, and circumferential directions passed the screening process. Out of these 16 studies, a meta-analysis was performed on the 10 studies that reported speckle tracking global longitudinal strain. Mean speckle tracking-derived global longitudinal strain was 21.0% (95% Confidence Interval 19.6-22.5%, strain given as positive values). When the studies were divided into subgroups, mean speckle tracking global longitudinal strain from the four-chamber view was 19.5% (95% Confidence Interval 18.0-21.0%) and that derived from all three apical views was 22.5% (95% CI 20.6-24.7%), indicating that global longitudinal strain from the four-chamber view is slightly lower than global longitudinal strain from all three apical views. Neonatal strain values were close to strain values in older subjects found in previous meta-analyses. Further studies are recommended that examine strain rate, segmental strain values, strain derived from short axis views, and strain in the first few hours after birth.