Different functional cardiac characteristics observed in term/preterm neonates by echocardiography and tissue doppler imaging

Cardiac Development and Related Clinical Considerations

The anatomy, physiology, and hemodynamics of the premature heart vary along the range of gestational ages cared for in neonatal intensive care units, from 22 weeks to term gestation. Clinical management of the preterm neonate should account for this heterogenous development. This requires an understanding of the impact of ex utero stressors on immature and disorganized cardiac tissue, the different state of hemodynamics across intracardiac shunts impacting the natural transition from fetal to neonatal life, and the effects of intensive pharmacologic and non-pharmacologic interventions that have systemic consequences influencing cardiac function. This article provides a review of the increasing but still limited body of literature on the anatomy, hemodynamics, and electrophysiology of the preterm heart with relevant clinical considerations.

Longitudinal Strain vs. Conventional Echocardiographic Parameters in the First Week of Life in Healthy Term Newborns

The first week of life is characterized by substantial alterations in hemodynamic conditions. Changes in myocardial contractility will reflect these changes. We aimed to assess right and left ventricular function on the third and seventh days of life in 50 healthy term newborns. To assess myocardial function, we used speckle tracking echocardiography. Pulsed-wave tissue Doppler imaging, M-mode, Doppler and pulsed-wave Doppler were also used to assess ventricular function. We found a significant increase in both right and left longitudinal strain and an increase in systolic and diastolic tissue Doppler velocities, whereas most other parameters remained unchanged. At both time points, the measured parameters were significantly greater for the right ventricle, but the changes with time were similar for both ventricles. We also found an increase in right ventricular outflow tract acceleration time as an indirect sign of decreasing pulmonary vascular resistance and an increase in systolic blood pressure, pointing to increasing systemic vascular resistance. Together with a decreasing proportion of patients with patent ductus arteriosus, the estimated left ventricular cardiac output decreased and right ventricular cardiac output increased but not to a statistically significant degree. In conclusion, the results of our study show how different echocardiographic techniques capture hemodynamic changes and changes in myocardial contractility and compliance. Both longitudinal strain and tissue Doppler imaging parameters seem to offer greater sensitivity in comparison with conventional echocardiographic parameters.

Perinatal factors impacting echocardiographic left ventricular measurement in small for gestational age infants: a prospective cohort study

INTRODUCTION

Infants born small for gestational age (SGA) have an increased risk of developing various cardiovascular complications. While many influencing factors can be adjusted or adapt over time, congenital factors also have a significant role. This study, therefore, seeks to explore the effect of perinatal factors on the left ventricular (LV) parameters in SGA infants, as assessed immediately after birth.

METHODS AND MATERIALS

This single-center prospective cohort study, conducted between 2014 and 2018, involved healthy SGA newborns born > 35 weeks' gestation, delivered at New York-Presbyterian Brooklyn Methodist Hospital, and a gestational age (GA)-matched control group of appropriate for gestational age (AGA) infants. Data analysis was performed using multivariate linear regression in STATA.

RESULTS

The study enrolled 528 neonates, 114 SGA and 414 AGA. SGA infants exhibited a mean GA of 38.05 weeks (vs. 38.54), higher male representation (69.3% vs. 51.5%), lower birth weight (BW) (2318g vs 3381g), lower Apgar scores at birth, and a higher rate of neonatal intensive care unit admission compared to AGA infants (41.2% vs.18.9%; p<0.001). Furthermore, SGA infants were more likely to be born to nulliparous women (63.16% vs. 38.16%; p<0.001), with lower body mass index (BMI) (29.8 vs. 31.7; p=0.004), a lower prevalence of gestational maternal diabetes (GDM) (14.9 % vs. 35.5%; p<0.001), and a higher prevalence of preeclampsia (18.4 % vs. 6.52%; p<0.001). BW was identified as the most significant predictor affecting most LV parameters in this study (p<0.001), except shortening fraction, asymmetric interventricular septal hypertrophy and Inter-ventricular septal thickness/LV posterior wall ratio (IVS/LVPW). Lower GA (coefficient = -0.09, p=0.002), insulin use in GDM (coefficient = 0.39, p=0.014), and low APGAR scores at 1 minute (coefficient = -0.07, p<0.001) were significant predictors of IVS during diastole (R-squared [R2]=0.24). High maternal BMI is marginally associated with LVPW during systole (R2=0.27, coefficient = 0.01, p=0.050), while male sex was a significant predictor of LV internal dimension during diastole (R2=0.29, p=0.033).

CONCLUSION

This study highlights the significant influence of perinatal factors on LV parameters in SGA infants, with BW being the most influential factor. Although LV morphology alone may not predict future cardiovascular risk in the SGA population, further research is needed to develop effective strategies for long-term cardiovascular health management in this population.

Normative echocardiography data of myocardial adaptation to extrauterine life: a review of prospective studies

Recent research has increased focus and interest in characterizing the physiology of the transition circulation using echocardiography. Critique of published normative neonatal echocardiography data among healthy term neonates has not been performed. We have performed a comprehensive literature review using the key terms: cardiac adaptation, hemodynamics, neonatal transition, term newborns. Studies were included if they had reported echocardiography indices of cardiovascular function in the presence of maternal diabetes, intrauterine growth restricted newborns and prematurity and had a comparison group of healthy term newborns within first seven postnatal days. Sixteen published studies evaluating transitional circulation in healthy newborns were included. There was marked heterogeneity in the methodologies used; specifically, inconsistency in time of evaluation and imaging techniques used makes it challenging to determine specific trends of expected physiologic changes. Some studies revealed nomograms for echocardiography indices, though limitations persist in terms of sample size, number of reported parameters and consistency of measurement technique. A comprehensive standardized echocardiography framework which includes consistent techniques for assessment dimensions, function, blood flow, pulmonary/systemic vascular resistance, and shunts pattern is warranted to ensure consistency in the use of echocardiography to guide care of healthy and sick newborns.

Patent ductus arteriosus (PDA) and pulmonary morbidity: can early targeted pharmacologic PDA treatment decrease the risk of bronchopulmonary dysplasia?

A persistent left-to-right shunt through a patent ductus arteriosus (PDA) increases the rate of pulmonary hydrostatic fluid filtration, impairs pulmonary mechanics, and prolongs the need for respiratory support. Infants with a moderate/large PDA shunt that persists for more than 7-14 days are at increased risk for developing bronchopulmonary dysplasia (BPD) if they also require invasive ventilation for more than 10 days. In contrast, infants who require invasive ventilation for less than 10 days have similar rates of BPD no matter how long they are exposed to a moderate/large PDA shunt. Although pharmacologic PDA closure decreases the risk of abnormal early alveolar development in preterm baboons that are ventilated for 2 weeks, the findings from recent randomized controlled trials, as well as a quality improvement project, suggest that routine early targeted pharmacologic treatments, as currently employed, do not appear to alter the incidence of BPD in human infants.

Cardiac morphology in neonates with fetal growth restriction

OBJECTIVE

Assess effects of fetal growth restriction (FGR) on cardiac modelling in premature and term neonates.

STUDY DESIGN

Prospective echocardiographic study of a cohort of FGR neonates (n = 21) and controls (n = 41) with normal prenatal growth and circulation.

RESULTS

Unadjusted for gestational age, birth weight, sex, and twin/singleton, Late-FGR neonates had smaller hearts than controls, with globular left ventricles and symmetrical right ventricles. Adjusted estimates showed smaller left ventricles and similarly sized right ventricles, with symmetrical left and right ventricles. Early-FGR (compared with Late-FGR) had smaller hearts and globular left ventricles in unadjusted estimates, but after adjustment, sizes and shapes were similar.

CONCLUSION

FGR had significant impact on cardiac modelling, seen in both statistical models unadjusted and adjusted for gestational age, birth weight, sex, and twin/singleton. The adjustments, however, refined the results and revealed more specific effects of FGR, thus underscoring the importance of statistical adjustments in such studies.

Prematurity blunts protein synthesis in skeletal muscle independently of body weight in neonatal pigs

BACKGROUND

Postnatal growth failure in premature infants is associated with reduced lean mass accretion. Prematurity impairs the feeding-induced stimulation of translation initiation and protein synthesis in the skeletal muscle of neonatal pigs. The objective was to determine whether body weight independently contributes to the blunted postprandial protein synthesis.

METHODS

Preterm and term pigs that were either fasted or fed were stratified into quartiles according to birth weight to yield preterm and term groups of similar body weight; first and second quartiles of preterm pigs and third and fourth quartiles of term pigs were compared (preterm-fasted, n = 23; preterm-fed, n = 25; term-fasted, n = 21; term-fed, n = 21). Protein synthesis rates and mechanistic target of rapamycin complex 1 (mTORC1) activation in skeletal muscle were determined.

RESULTS

Relative body weight gain was lower in preterm compared to term pigs. Prematurity attenuated the feeding-induced increase in mTORC1 activation in longissimus dorsi and gastrocnemius muscles (P < 0.05). Protein synthesis in gastrocnemius (P < 0.01), but not in longissimus dorsi muscle, was blunted by preterm birth.

CONCLUSION

A lower capacity of skeletal muscle to respond adequately to feeding may contribute to reduced body weight gain and lean mass accretion in preterm infants.

IMPACT

This study has shown that the feeding-induced increase in protein synthesis of skeletal and cardiac muscle is blunted in neonatal pigs born preterm compared to pigs born at term independently of birth weight. These findings support the notion that preterm birth, and not low birth weight, impairs the capacity of skeletal and cardiac muscle to upregulate mechanistic target of rapamycin-dependent anabolic signaling pathways and protein synthesis in response to the postprandial increase in insulin and amino acids. These observations suggest that a blunted anabolic response to feeding contributes to reduced lean mass accretion and altered body composition in preterm infants.

Left ventricular systolic function in subjects conceived through assisted reproductive technologies

Background

Over the past decades, assisted reproductive technologies (ART) have gained remarkable influence in the treatment of infertility and account for more than 2 % of births in European countries nowadays. Accumulating evidence suggests ART to cause cardiovascular alterations, including left ventricular (LV) dysfunctions, within its offspring. The aim of this study was to assess LV systolic function in subjects conceived through ART in comparison to spontaneously conceived peers.

Methods

For the assessment of LV morphology and LV function, M-Mode echocardiography, pulsed wave Doppler and two-dimensional speckle tracking echocardiography (2DSTE) were applied. LV ejection fraction (EF) and fractional shortening (FS) were assessed in M-Mode and calculated by Teichholz formula. EF was additionally assessed semiautomatically through 2DSTE.

Results

In total, 64 ART subjects and 83 spontaneously conceived controls with no significant differences in age (12.52 ± 5.64 years vs. 13.20 ± 5.95 years, p = 0.486) and sex were included in the analysis. In the ART cohort, significantly lower values were observed for M-Mode assessed EF (63.63 ± 5.17 % vs. 65.35 ± 5.10 %, p = 0.046) and FS (34.26 ± 3.87 % vs. 35.60 ± 3.84 %, p = 0.038). However, after the adjustment for birth weight percentile and gestational age, M-Mode assessed EF and FS displayed no significant differences between both groups. LV morphology and remaining systolic function parameters, such as mitral annular plane systolic excursion, aortic velocity time integral, global peak longitudinal strain and 2DSTE measured EF, were comparable between both groups.

Conclusion

This study suggests a lower LV systolic function in ART subjects, visualized by significantly lower values for M-Mode assessed EF and FS, compared to spontaneously conceived peers. The clinical relevance of these findings has to be investigated as the above-mentioned parameters were in normal reference range. In addition, LV systolic function parameters evaluated by other echocardiographic imaging modalities were comparable between both groups. Therefore, further studies will be required to evaluate the influence of ART on LV systolic function and cardiovascular morbidity in the future.

Right Ventricular Function in Neonates During Early Postnatal Period: A Prospective Observational Study

Previous echocardiographic studies were mainly focused on preterm infants and early fetal-to-neonatal transition period, whereas little is known about changes in the parameters of the right ventricular (RV) function after 72 h of life. Our aim was to quantitatively characterize potential changes in RV function by echocardiography in healthy term newborns between the third and the seventh day of life. We conducted a prospective observational study in 35 full-term newborns, in whom we performed echocardiographic examinations on the third and the seventh day of life. We assessed RV function, output and afterload and found a significant increase in all tissue Doppler velocities as well as in RV longitudinal strain, a higher mean RV outflow tract velocity time integral and lower myocardial performance index (MPI'), whereas the tricuspid annular plane systolic excursion, RV filling pattern, and RV outflow tract acceleration time were not significantly different between the third and the seventh day of life. Conclusions: Increased RV systolic and diastolic myocardial velocities, cardiac output and longitudinal deformation and decreased RV MPI' between the third and the seventh day of life point to a reduction of RV afterload and adaptive myocardial maturation in term newborns during this period. Moreover, PW-TDI and 2D speckle-tracking echocardiography seem to be more sensitive for evaluating RV function in comparison with M-mode echocardiography and pulsed-wave Doppler analysis of RV filling.

Echocardiographic Assessment of Right Ventricular Function in Paediatric Heart Disease: A Practical Clinical Approach

As the right ventricle (RV) plays an integral role in different paediatric heart diseases, the accurate assessment of RV size and function is essential in the diagnosis, management, and prognostication of congenital and acquired cardiac lesions. Yet, echocardiographic evaluation of the RV is challenging because of its complex and variable morphology, its different physiology compared with the left ventricle, and its capability to adapt to different loading conditions associated with congenital and acquired heart diseases within certain ranges. Reliable echocardiographic detection of RV systolic and diastolic dysfunction remains challenging while important for patient management. This review provides an updated, practical approach to assessing RV function in structurally normal hearts and in children with common congenital heart defects and in those with pulmonary hypertension. We also review the impact of tricuspid valve function on RV functional parameters. There is no single functional RV parameter that uniquely describes RV function; instead a combination of different parameters is recommended in clinical practice. Qualitative and quantitative analysis of RV function will be reviewed including more recent techniques such as speckle tracking and 3D echocardiography.

Linking the Perinatal Environment to Neonatal Cardiovascular Outcomes

Cases of high-risk pregnancies continue to rise throughout the United States and globally, increasing rates of maternal and neonatal morbidity. Common pregnancy complications and morbidities include preterm birth, hypertensive disorders, fetal growth restriction, diabetes mellitus, and chorioamnionitis. Exposure to these perinatal conditions contributes to cardiac morbidities in the fetus and neonate, including altered cardiac growth, congenital heart disease, and cardiac dysfunction. Significant research has demonstrated lasting effects of these pregnancy complications, with increased rates of cardiac morbidities seen in children and adults after these perinatal exposures. The link between the perinatal environment and long-term outcomes has not been fully elucidated. The aim of this review is to discuss the current understanding of the implications of a high-risk pregnancy on fetal and neonatal cardiac development.

Normal Values and Patterns of Normality and Physiological Variability of Mitral and Tricuspid Inflow Pulsed Doppler in Healthy Children

Background: While mitral (MV) and tricuspid valve (TV) pulsed Doppler velocities and derived gradients are commonly evaluated, data on normal pediatric values are limited. This study aimed to evaluate the normal values and physiological variability for MV and TV Doppler velocities and derived gradients in a large cohort of prospectively enrolled healthy children. Methods: The echocardiographic measurements included pulsed Doppler MV and TV E and A velocities, E deceleration times (EDT), maximal and mean gradients, and velocity time integral (VTI). Results: A total of 544 healthy subjects (median age 6.4 years, range 1 day–17.68 years) were included. MV and TV E velocity, E/A ratio, and E and A wave duration increased, while A velocity decreased with age (p < 0.001). Along with an increase in VTI, there occurred a progressive increase in maximum velocity and gradients and a decrease in mean velocities and gradients. E/A inversions were common, especially at the TV in neonates and infants. For MV, inversion in either one, two, or three consecutive beats occurred in 51.9% of neonates and 18.3% of infants, while it was rare at older ages (all p < 0.001). For TV, inversions in three consecutive beats occurred in 71.4% of neonates, while inversions in only one or two beats were more common in infants (27.3%). For TV, inversion in one or more beats, however, was not infrequent at all ages. Conclusions: We report normal values and patterns of normality and physiological variability for MV and TV inflow Doppler from a large population of healthy children.

Hemodynamic considerations in preterm infants born at less than 25 weeks gestation

As survival rates continue to improve for infants born at less than 25 weeks gestation, delineating normal cardiovascular physiology from pathophysiology becomes much more challenging. With a paucity of 'normative' data for such infants, an over-reliance on studies at older gestations can result in a 'best guess' approach. Here we offer a pragmatic approach to these diagnostic challenges from a cardiovascular viewpoint. An appreciation of the unique physiology, from the immature myocardium and altered vascular tone to an innately large patent ductus arteriosus is essential, as is a thorough history for case specific contributing factors. We explore the additional difficulties in achieving a balance between minimal handling at the bedside and delineating important objective markers of perfusion. Finally, we discuss treatment approaches including inotrope therapy and patent ductus treatment, acknowledging the limited data available to guide these decisions.

Comparative evaluation of echocardiography indices during the transition to extrauterine life between small and appropriate for gestational age infants

OBJECTIVES

To study changes in heart function and hemodynamics during the transitional period in small for gestational (SGA) infants and appropriate (AGA) healthier counterparts.

DESIGN

A hospital based prospective observational study was performed at a perinatal center. Echocardiograms were performed on the first postnatal day and again at 48 h age. Term SGA infants were compared with those AGA newborns matched for the GA and mode of delivery.

RESULTS

Eighteen SGA infants were compared with 18 AGA infants [gestation 38 ± 1.5 vs. 38 ± 1.2 weeks, p > 0.05 and birthweight 2331 ± 345 vs. 3332 ± 405 grams, p < 0.05, respectively]. Maternal weight and body mass index was higher among non-affected pregnancies, 61% infants were born vaginally, and no differences in cord blood pH at birth were noted. SGA infants had higher systolic and mean blood pressure at both time points, lower indices of right ventricular (RV) performance [TAPSE (tricuspid annular peak systolic excursion) 7.4 ± 2.8 vs. 9.3 ± 0.7 on day 1, 7.2 ± 2.8 vs. 9.2 ± 0.5 on day 2, p = 0.001], lower pulmonary acceleration time (PAAT) suggestive of elevated pulmonary vascular resistance [56.4 ± 10.5 vs. 65.7 ± 13.2 on day 1, 61.4 ± 12.5 vs. 71.5 ± 15.7 on day 2, p = 0.01] and higher left ventricular (LV) ejection fraction [62.1 ± 7.8 vs. 54.9 ± 5.5 on day 1, 61.9 ± 7.6 vs. 55.8 ± 4.9 on day 2, p = 0.003].

CONCLUSIONS

SGA infants had evidence of higher pulmonary vascular resistance, and lower RV performance during the postnatal transition. The relevance and impact of these changes to hemodynamic disease states during the postnatal transition requires prospective investigation.

Association between Metabolic Syndrome Components and Cardiac Autonomic Modulation among Children and Adolescents: A Systematic Review and Meta-Analysis

Simple Summary

The clustering of metabolic syndrome (MetS) risk factors is becoming more prevalent in young people (up to the age of 19 years) leading to the development of type 2 diabetes (T2D) and cardiovascular diseases in early adulthood. The impact of MetS risk factors on cardiac autonomic modulation (CAM) or vice versa have been noted to track from childhood to pre-adolescence and adolescence. Understating associations in this age group may help improve the clinical outcomes of the MetS, even when MetS symptoms are not visible. Potential damage from each individual MetS component and the ability to predict early cardiac damage or upcoming cardiovascular events is very important. Therefore, the present systematic review and meta-analysis investigated the associations between CAM and MetS risk factors individually to verify which MetS risk components were significantly correlated with which heart rate variability (HRV) indices before or at the onset of the MetS among young people. The purpose of this review was to outline the importance of potentially screening HRV indices in young people even with only one MetS risk factor, as a pre-indicator for early cardiovascular risk stratification. Cross-sectional studies that examined the relationship of MetS risk factors with HRV indices were searched using four databases including PubMed, the Cochrane clinical trials library, Medline and the Web of Science. Correlation coefficients with 95% confidence intervals (95% CI), and random effects meta-analyses of the association between MetS risk factors with HRV indices were performed. Our results propose that lipid profiles including high density lipoprotein (HDL) and triglycerides (TGs), waist circumference (WC) and blood pressure (BP) are associated with CAM in young people up to the age of 19 years. The use of HRV indices to predict future MetS risk, and relationships with individual risk factors including HDL, BP, WC and TGs, were established. Furthermore, arterial pressure, respiration, stress and physical activity must be taken into consideration for future studies along with CAM related to young people (up to the age of 19 years), and it is recommended to explore further the associations reported here, as CAM is not the only determinant of neurovisceral regulation.

Abstract

Background: the clustering of metabolic syndrome (MetS) risk factors is becoming more prevalent in children, leading to the development of type 2 diabetes (T2D) and cardiovascular diseases in early adulthood. The impact of MetS risk factors on cardiac autonomic modulation (CAM) or vice versa has been noted to track from childhood to pre-adolescence and adolescence. Understating associations in this age group may help to improve the clinical outcomes of the MetS, even when MetS symptoms are not visible. Potential damage from each individual MetS component and the ability to predict early cardiac damage or upcoming cardiovascular events is very important. Therefore, the present systematic review and meta-analysis investigated the associations between CAM and MetS risk factors individually to verify which of the MetS risk components were significantly correlated with heart rate variability (HRV) indices before or at the onset of the MetS among young people. The purpose of this review was to outline the importance of potentially screening HRV indices in young people even with only one MetS risk factor, as a pre-indicator for early cardiovascular risk stratification. Methods: cross-sectional studies that examined the relationship of MetS risk factors with HRV indices were searched using four databases including PubMed, the Cochrane clinical trials library, Medline and the Web of Science. Correlation coefficients with 95% confidence intervals (95% CI), and random effects meta-analyses of the association between MetS risk factors with HRV indices were performed. Results: out of 14 cross-sectional studies and one case-control study, 8 studies (10 data sets) provided association data for the meta-analysis. Our results indicated significant positive correlations for systolic blood pressure (SBP) (correlation coefficient 0.13 (95%CI: 0.06; 0.19), I² = 47.26%) and diastolic blood pressure (DBP) (correlation coefficient 0.09 (95%CI: −0.01; 0.18), I² = 0%) with a Low Frequency/High Frequency ratio (LF/HF). Significant negative correlations for waist circumference (WC) (correlation coefficient −0.12 (95%CI: −0.19; −0.04), I² = 51.50%), Triglycerides (TGs) (correlation coefficient −0.09 (95%CI: −0.15; −0.02), I² = 0%) and ≥2 MetS risk factors (correlation coefficient −0.10 (95%CI: −0.16; −0.03), I² = 0%); with high frequency (HF) were revealed. Significant positive correlations for high density lipoprotein (HDL) (correlation coefficient 0.08 (95%CI: 0.05; 0.11), I² = 0%) and significant negative correlations of ≥2 MetS risk (correlation coefficient −0.04 (95%CI: −0.12; 0.03), I² = 0.0%) with low frequency (LF) were revealed. Significant negative correlations for TGs (correlation coefficient −0.09 (95%CI: −0.23; 0.05), I² = 2.01%) with a mean square root of the sum of differences between mean time between two successive intervals (rMSSD) and significant positive correlation of HDL (correlation coefficient 0.09 (95%CI: −0.01; 0.19), I² = 0.33%) with standard deviation of the time between two successive intervals (SDNN) were also revealed. An Egger’s test indicated that there was no obvious publication bias for any of the above relationships except for TGs and rMSSD. The significance level stipulated for the meta-analysis was p < 0.05. Conclusions: lipid profiles (HDL and TGs), WC and BP were associated with CAM in young people up to the age of 19 years. The use of HRV indices to predict future MetS risk, and relationships with individual risk factors including HDL, BP, WC and TGs, were established. Future studies related to young people (up to the age of 19 years) are recommended to explore the associations reported here further.

Left Ventricle Phenotyping Utilizing Tissue Doppler Imaging in Premature Infants with Varying Severity of Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is characterized by alveolar-capillary simplification and is associated with pulmonary hypertension (PH) in preterm infants. The contribution of left ventricle (LV) disease towards this severe BPD-PH phenotype is not well established. We aimed to describe the longitudinal trajectory of the LV function as measured by tissue Doppler imaging (TDI) and its association with BPD-PH. We retrospectively assessed prospectively acquired clinical and echocardiographic data from 77 preterm infants born between 2011 and 2013. We characterized the LV function by measuring systolic and diastolic myocardial velocities (s’, e’, a’), isovolumetric relaxation time (IVRT), and myocardial performance index with TDI at three time periods from 32 and 36 weeks, postmenstrual age through one year of age. We also measured post systolic motion (PSM), a marker of myocardial dysfunction that results from asynchronous movement of the ventricular walls, and not previously described in preterm infants. Patients were stratified into groups according to BPD severity and the presence of PH and compared over time. Conventional TDI measures of the LV function were similar between groups, but the septal PSM was significantly prolonged over the first year of age in patients with BPD-PH. PSM provides a novel objective way to assess the hemodynamic impact of lung and pulmonary vascular disease severity on LV function in preterm infants with BPD and PH.

Myocardial performance index in term appropriate and small for gestational age neonates - a cross sectional study

BACKGROUND

It is known that small for gestational age (SGA) babies may be at an increased risk of cardiovascular diseases during adulthood. There is paucity of literature regarding comparative cardiac functions of SGA and appropriate for gestational age (AGA) babies in neonatal period. The present study was conceived to compare the cardiac function of term small and appropriate for gestational age (AGA) babies through a relatively novel echocardiographic index in early neonatal period.

OBJECTIVES

To compare values of myocardial performance index (MPI) index (MPI = IVCT + IVRT/ET) at 48-72 hours of age among AGA and SGA babies.

METHODS

Morphological and anthropometric assessment of serially born term babies was done at time of birth to recruit hundred each of AGA and SGA babies. Tissue Doppler Imaging (TDI) was done between 48-72 hours for each enrolled baby to assess both right and left ventricle MPI in each group.

RESULTS

Mean±SD values for right ventricular MPI in AGA and SGA groups were 0.268 + 0.007 and 0.30 + 0.026 respectively (p < 0.001). Mean±SD values for left ventricular MPI in AGA and SGA groups were 0.25 + 0.012 and 0.30 + 0.017 respectively (p < 0.001). There was significant negative correlation between MPI values for either ventricles and the birth weight (spearmen's rho of -0.66) (p < 0.001). Mean±SD values for LVET in AGA and SGA group were 0.304 + 0.026 and 0.266 + 0.032 respectively (p < 0.001).

CONCLUSION

MPI had a higher absolute value in the SGA babies as compared to AGA babies. These observations point towards suboptimal cardiac performance among SGA babies as compared to AGA babies on the basis of myocardial performance index.

Chronological echocardiographic evaluation of left ventricular systolic and diastolic function in term and premature neonatal calves

Echocardiographic studies in human neonatology has demonstrated that prematurity can lead to cardiovascular dysfunction and especially compromises the left ventricular (LV) systolic and diastolic functions. As echocardiographic studies have not been performed on cardiovascular dysfunction in premature calves, we echocardiographically evaluated and compared the LV systolic and diastolic function in full-term and premature calves. We followed the hemodynamical changes of LV during first 3 days of life. Twenty premature calves and 10 healthy term calves were enrolled in the study. 2D, M-mode and Doppler echocardiographic examinations were performed at days 1, 2 and 3 after birth to evaluate LV systolic and diastolic functions. Our findings demonstrated that not only was there LV diastolic dysfunction (55% premature calves, 10% term calf at day 1; 65% premature calves, 10% term calf at day 2 and, 75% premature calves, 20% term calf at day 3), but also LV systolic dysfunction (55% premature calves, 60% term calf at day 1; 55% premature calves, 50% term calf at day 2, and 45% premature calves, 40% term calf at day 3) deteriorated in both term and premature calves. In conclusion, the present study, which was the first comparative echocardiographic assessment of LV systolic and diastolic functions in term and premature newborn calves, showed that both systolic and diastolic dysfunctions might occur in term and premature calves.

Early postnatal cardiac follow-up of survivors of twin-twin transfusion syndrome treated with fetoscopic laser coagulation

OBJECTIVE

To assess the cardiac function and prevalence of congenital heart defects (CHD) in twin-twin transfusion syndrome (TTTS) survivors.

STUDY DESIGN

Prospective follow-up of TTTS pregnancies treated with laser surgery (2015-2018). Echocardiography was performed 1 day and 1 month after birth (corrected for prematurity). Results were compared with a control group of age-matched uncomplicated monochorionic twin-pairs at 1 month.

RESULT

Eighty-nine TTTS (168 neonates) and nine control pregnancies (18 neonates) were enrolled. CHD birth prevalence was 9.2% (8/87) in recipients and 13.6% (11/81) in donors (p = 0.37). Four of 19 (21%) were detected prenatally, all pulmonary stenosis. Donors had lower aortic peak velocities compared with recipients at day 1 (0.66 ± 0.15 m/s vs 0.71 ± 0.19 m/s, p = 0.04) and 1 month (1.04 ± 0.21 m/s vs 1.11 ± 0.18 m/s, p = 0.02), but not compared with controls.

CONCLUSION

CHD prevalence in TTTS survivors is high, with a low prenatal detection of minor abnormalities. Follow-up fetal echocardiograms and a postnatal echocardiogram should be offered.

Changes in the Preterm Heart From Birth to Young Adulthood: A Meta-analysis

CONTEXT

Preterm birth is associated with incident heart failure in children and young adults.

OBJECTIVE

To determine the effect size of preterm birth on cardiac remodeling from birth to young adulthood.

DATA SOURCES

Data sources include Medline, Embase, Scopus, Cochrane databases, and clinical trial registries (inception to March 25, 2020).

STUDY SELECTION

Studies in which cardiac phenotype was compared between preterm individuals born at <37 weeks' gestation and age-matched term controls were included.

DATA EXTRACTION

Random-effects models were used to calculate weighted mean differences with corresponding 95% confidence intervals.

RESULTS

Thirty-two observational studies were included (preterm = 1471; term = 1665). All measures of left ventricular (LV) and right ventricular (RV) systolic function were lower in preterm neonates, including LV ejection fraction (P = .01). Preterm LV ejection fraction was similar from infancy, although LV stroke volume index was lower in young adulthood. Preterm LV peak early diastolic tissue velocity was lower throughout development, although preterm diastolic function worsened with higher estimated filling pressures from infancy. RV longitudinal strain was lower in preterm-born individuals of all ages, proportional to the degree of prematurity (R ² = 0.64; P = .002). Preterm-born individuals had persistently smaller LV internal dimensions, lower indexed LV end-diastolic volume in young adulthood, and an increase in indexed LV mass, compared with controls, of 0.71 g/m² per year from childhood (P = .007).

LIMITATIONS

The influence of preterm-related complications on cardiac phenotype could not be fully explored.

CONCLUSIONS

Preterm-born individuals have morphologic and functional cardiac impairments across developmental stages. These changes may make the preterm heart more vulnerable to secondary insults, potentially underlying their increased risk of early heart failure.

Measurement of inotropy and systemic oxygen delivery in term, low- and very-low-birth-weight neonates using the Ultrasonic Cardiac Output Monitor (USCOM)

Background The aim of this study was to assess the normal values of the Smith-Madigan inotropy index (SMII) and oxygen delivery index (DO2I) in low-birth-weight (LBW) and very-low-birth-weight (VLBW) newborns on the first 3 days of life, and to identify how different degrees of maturity influence cardiovascular alterations during the transitional period compared with term neonates. Methods Twenty-eight VLBW newborns, 46 LBW newborns and 50 normal full-term newborns admitted to our department were studied. Hemodynamics of the left heart were measured in all neonates over the first 3 days using the Ultrasonic Cardiac Output Monitor (USCOM). This was combined with hemoglobin concentration and pulse oximetry to calculate DO2I. Blood pressure was combined with the hemodynamic measures and hemoglobin concentration to calculate SMII. Results SMII showed statistically significant differences among the three groups (VLBW 0.48 ± 0.11; LBW 0.54 ± 0.13; term 0.69 ± 0.17 W/m2 P < 0.001), which was in line with the following myocardial parameters: stroke volume index (SVI) and cardiac index (CI) (P < 0.001 and <0.001). For systemic oxygen delivery (DO2) parameters, significant differences were found for DO2I (P < 0.001) while hemoglobin concentration and pulse oximetry demonstrated no significant differences. In the VLBW group, SMII and DO2I showed no significant change over the 3 days. Conclusion Normal inotropy and systemic DO2I values in VLBW neonates over the first 3 days of life were assessed. SMII and DO2I were significantly lower in VLBW neonates during the first 72 h of life. With increasing birth weight, higher myocardial inotropy and DO2 were found. The addition of USCOM examination to standard neonatal echocardiography may provide further important information regarding cardiac function.

Myocardial Function Maturation in Very-Low-Birth-Weight Infants and Development of Bronchopulmonary Dysplasia

Background: Myocardial function in very-low-birth-weight infants (VLBWIs) develops during early postnatal life, but different patterns of temporal evolution that might be related to the development of bronchopulmonary dysplasia (BPD) are not completely understood. Methods: A prospective cohort study including VLBWIs admitted to our NICU from January 2015 to 2017 was conducted. Plasma N-terminal pro B type natriuretic peptide (NTproBNP) levels were measured, and echocardiograms were performed at 24 and 72 h of life and weekly thereafter until 36 weeks of postmenstrual age (PMA). We measured the tricuspid annular plane systolic excursion (TAPSE) by M-mode; the lateral tricuspid E', A', and S' waves; and the myocardial performance index (MPI) by tissue doppler imaging (TDI). The subjects were divided into non-BPD and BPD groups. Results: We included 101 VLBWIs. The TAPSE and E', A', and S' waves increased while MPI-TDI decreased over time. Birth gestational age (GA) and postnatal PMA impacted these parameters, which evolved differently in those who developed BPD compared to those in the non-BPD group. The NTproBNP levels at 14 days of life and different echocardiographic parameters were associated with the development of BPD in different multivariate models. Conclusion: TAPSE and TDI values depend on GA and PMA and follow a different temporal evolution that is related to the later development of BPD. Combined biochemical and echocardiographic biomarkers can help identify which VLBWIs are at higher risk of developing BDP.

Chronological Echocardiographic Changes in Healthy Term Neonates within Postnatal 72 Hours Using Doppler Studies

BACKGROUND

This study evaluated echocardiographic changes in full-term healthy neonates during early transitional period from postnatal 0-72 hours at 12-hour intervals by echocardiography.

METHODS

This was a prospective, observational, and longitudinal single-center cohort study. Morphometric, functional, systolic, diastolic, and tissue Doppler imaging (TDI) parameters (patent ductus arteriosus [PDA], aorta, superior vena cava [SVC], stroke volume [SV], cardiac output [CO], cardiac index [CI], early diastolic flow velocity [E], late diastolic flow velocity [A], early filling in TDI [E'], peak systolic annular velocity in TDI [S'], late velocity peak in TDI [A'], and myocardial performance index [MPI]) were evaluated in left ventricle (LV) and right ventricle (RV) with 56 newborns.

RESULTS

Sizes and peak velocities of PDA before postnatal 24 hours were significantly changed than those after postnatal 24 hours. Aortic velocity time integral (VTI), systolic blood pressure (BP), LV SV/kg, LV CO/kg, LV CI, and SVC flow/LV CO before 24 hours showed significantly changes than those after 24 hours. Also, LV and RV MPI before 24 hours were significantly higher than those after 24 hours. LV E/E' was significantly higher than RV E/E'.

CONCLUSION

Postnatal 24 hours is critical time for hemodynamic closure of PDA because aortic VTI, systolic BP, LV SV, LV CO, LV CI, and SVC flow/LV CO showed simultaneously significant changes after 24 hours at the same time as 24 hours of physiological closure of PDA. Chronological and dramatic changes of systolic, diastolic, and TDI parameters during early postnatal period can be used to compile normal baseline data of healthy full-term neonates.

Neonatal Growth Restriction Slows Cardiomyocyte Development and Reduces Adult Heart Size

Prematurity is associated with reduced cardiac dimensions and an increased risk of cardiovascular disease. While prematurity is typically associated with ex utero neonatal growth restriction (GR), the independent effect of neonatal GR on cardiac development has not been established. We tested the hypothesis that isolated neonatal GR decreases cardiomyocyte growth and proliferation, leading to long-term alterations in cardiac morphology. C57BL/6 mice were fostered in litters ranging in size from 6 to 12 pups to accentuate normal variation in neonatal growth. Regardless of litter size, GR was defined by a weight below the 10th percentile. On postnatal day 8, Ki67 immunoreactivity, cardiomyocyte nucleation status and cardiomyocyte profile area were assessed. For adult mice, cardiomyocyte area was determined, along with cardiac dimensions by echocardiography and cardiac fibrosis by Masson's trichrome stain. On day 8, cardiomyocytes from GR versus control mice were significantly smaller and less likely to be binucleated with evidence of persistent cell cycle activity. As adults, GR mice continued to have smaller cardiomyocytes, as well as decreased left ventricular volumes without signs of fibrosis. Neonatal GR reduces cardiomyocyte size, delays the completion of binucleation, and leads to long-term alterations in cardiac morphology. Clinical studies are needed to ascertain whether these results translate to preterm infants that must continue to grow and mature in the midst of the increased circulatory demands that accompany their premature transition to an ex utero existence. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc.

Tissue Doppler velocity imaging and event timings in neonates: a guide to image acquisition, measurement, interpretation, and reference values

Neonatologists can use echocardiography for real-time assessment of the hemodynamic state of neonates to support clinical decision-making. There is a large body of evidence showing the shortcomings of conventional echocardiographic indices in neonates. Newer imaging modalities have evolved. Tissue Doppler imaging is a new technique that can provide measurements of myocardial movement and timing of myocardial events and may overcome some of the shortcomings of conventional techniques. The high time resolution and its ability to assess left and right cardiac function make tissue Doppler a favorable technique for assessing heart function in neonates. The aim of this review is to provide an up-to-date overview of tissue Doppler techniques for the assessment of cardiac function in the neonatal context, with focus on measurements from the atrioventricular (AV) plane. We discuss basic concepts, protocol for assessment, feasibility, and limitations, and we report reference values and give examples of its use in neonates.

Monitoring Circulation During Transition in Extreme Low Gestational Age Newborns: What's on the Horizon?

Echocardiography and near-infrared spectroscopy have significantly changed our view on hemodynamic transition of the extreme preterm infant. Instead of focusing on maintaining an arbitrary target value of blood pressure, we aim for circulatory well-being by a comprehensive holistic assessment of markers of cardiovascular instability. Most of these clinical and biochemical indices are influenced by transition itself and remain poor discriminators to identify patients with a potential need for therapeutic intervention. At the same time, the evolution in data capturing and storage has led to a change in our approach to monitor vital parameters. Continuous trend monitoring has become more and more relevant. By using signal extraction methods, changes in trends over time can be quantified. In this review, we will discuss the impact of these innovations on the current monitoring practices and explore some of the potential benefits these techniques may have in improving real-time detection of extreme low birth weight infants at risk for morbidity related to impaired hemodynamic transition.

Pulmonary Artery Pressures in School-Age Children Born Prematurely

OBJECTIVES

To test the hypothesis that pulmonary artery pressures were higher in school aged children born extremely premature than those born at term. We also wanted to assess whether pulmonary artery pressures differed between children born prematurely with or without bronchopulmonary dysplasia (BPD) or between those randomized in the neonatal period to different ventilation modes.

STUDY DESIGN

Transthoracic echocardiography was performed on 193 children born extremely premature (106 had BPD) and 110 children born at term when they were 11-14 years of age. Ninety-nine children born extremely premature had been supported by high-frequency oscillation and 94 by conventional ventilation. Tricuspid regurgitation was assessed in the apical 4-chamber and modified parasternal long-axis views. Continuous-wave Doppler of the peak regurgitant jet velocity was used to estimate the right-ventricular-to-right-atrial systolic pressure gradient.

RESULTS

Tricuspid regurgitation was measurable in 71% (137/193) of the children born preterm and 75% (83/110) of the children born at term (P .23). The children born prematurely compared with the children born at term had a greater peak tricuspid regurgitation velocity (2.21 vs 1.95 m/s, P < .001) and the children born prematurely who had BPD vs those without BPD had a greater peak tricuspid regurgitation velocity (P = .023). There were no significant differences in pulmonary artery pressures according to neonatal ventilation mode.

CONCLUSIONS

Pulmonary artery pressures were estimated to be greater in 11- to 14-year-old children born extremely prematurely compared with those born at term and in those born prematurely who developed BPD compared with those who did not but did not differ significantly by neonatal ventilation mode.

Cardiac Morphology and Function in Preterm Growth Restricted Infants: Relevance for Clinical Sequelae

OBJECTIVES

To assess cardiac morphology and function in preterm infants with fetal growth restriction (FGR) compared with an appropriate for gestational age cohort, and to ascertain clinical correlation with neonatal sequelae.

STUDY DESIGN

With informed consent, 20 infants born between 28 and 32 weeks of gestational age and birthweight (BW) <10th percentile were compared using conventional and tissue Doppler echocardiography with 20 preterm appropriate for gestational age infants. Total duration of respiratory support was recorded.

RESULTS

The gestational age and BW of the infants with FGR and appropriate for gestational age infants were 29.8 ± 1.3 weeks vs 30 ± 0.9 weeks (P = .78) and 923.4 ± 168 g vs 1403 ± 237 g (P < .001), respectively. Preterm infants with FGR had significantly greater interventricular septal hypertrophy, greater free wall thickening, and lower sphericity indices (1.53 ± 0.15 vs 1.88 ± 0.2; P < .001), signifying globular and hypertrophied hearts. The transmitral E/A ratio and isovolumic relaxation time, markers of diastolic function, were significantly increased in the FGR cohort (0.84 ± 0.05 vs 0.78 ± 0.03 [P < .001] and 61.4 ± 4.1 ms vs 53.2 ± 3.2 ms [P < .001], respectively). Ejection fraction, as measured by the rate corrected mean velocity of circumferential fiber shortening was reduced (1.93 ± 0.4 circ/second vs 2.77 ± 0.5 circ/second; P < .001) in the FGR cohort. On follow-up, the total duration of respiratory support was significantly longer in the FGR cohort, and correlated with tissue Doppler E/E' (r = 0.65; P = .001), mean velocity of circumferential fiber shortening (r = -0.64; P = .001) and mitral annular peak systolic excursion (r = -0.57; P = .008).

CONCLUSIONS

Preterm infants with FGR have altered cardiac function evident within days after birth, which is associated with respiratory sequelae.

Disproportionate cardiac hypertrophy during early postnatal development in infants born preterm

BackgroundAdults born very preterm have increased cardiac mass and reduced function. We investigated whether a hypertrophic phenomenon occurs in later preterm infants and when this occurs during early development.MethodsCardiac ultrasound was performed on 392 infants (33% preterm at mean gestation 34±2 weeks). Scans were performed during fetal development in 137, at birth and 3 months of postnatal age in 200, and during both fetal and postnatal development in 55. Cardiac morphology and function was quantified and computational models created to identify geometric changes.ResultsAt birth, preterm offspring had reduced cardiac mass and volume relative to body size with a more globular heart. By 3 months, ventricular shape had normalized but both left and right ventricular mass relative to body size were significantly higher than expected for postmenstrual age (left 57.8±41.9 vs. 27.3±29.4%, P<0.001; right 39.3±38.1 vs. 16.6±40.8, P=0.002). Greater changes were associated with lower gestational age at birth (left P<0.001; right P=0.001).ConclusionPreterm offspring, including those born in late gestation, have a disproportionate increase in ventricular mass from birth up to 3 months of postnatal age. These differences were not present before birth. Early postnatal development may provide a window for interventions relevant to long-term cardiovascular health.

Serial measures of cardiac performance using tissue Doppler imaging velocity in preterm infants <29weeks gestations

INTRODUCTION

Tissue Doppler imaging (TDI) is a useful marker of myocardial performance in preterm infants. We aimed to demonstrate serial changes in TDI velocity in preterm infants <29weeks gestation, to assess the impact of inotropes and a haemodynamically significant patent ductus arteriosus (hsPDA).

METHODS

This was a prospective observational study of preterm infants <29weeks gestation. Echocardiography was performed at days 1, 2, 5-7 and at 36weeks, or before hospital discharge. Infants with hsPDA's on day 5-7 and those who received inotropes in the first week of life were not included in the Reference Cohort. Systolic (s`) and diastolic (e` and a`) velocity waves were assessed at the mitral and tricuspid annulus and basal septum.

RESULTS

One hundred and thirty nine infants with a mean (SD) gestation and birthweight of 26.7 (1.5) weeks and 946 (247) grams were enrolled. The 66 infants (47%) in the Reference Cohort demonstrated an increase in functional parameters with increasing age [LV s`, Septal s`, and RV s`, Day 1-36weeks: 2.8 (0.6) to 4.7 (1.0), 2.4 (0.6) to 4.6 (0.8), 3.6 (0.6) to 6.9 (1.0) cm/s respectively; all p<0.05). The 24 infants who received inotropes had lower LV e` [2.9 vs. 3.6cm/s], Septal e` [2.3 vs. 2.8cm/s] and a` [3.2 vs. 3.9cm/s], and lower RV a` [3.3 vs. 3.9cm/s] on Day 1 (all p<0.05). Fifty five infants had a hsPDA on Day 5-7, demonstrating higher LV [4.7 vs. 4.0cm/s] and Septal e` [3.9 vs. 3.3cm/s], and a higher LV E/e` [13 vs. 10] (all p<0.05).

CONCLUSION

Extremely preterm infants display a gradual increase in tissue Doppler velocities from birth until 36weeks corrected age. The presence of a hsPDA increases diastolic TDI velocities. Infants requiring inotropes have lower diastolic myocardial velocities on Day 1.

Echocardiographic evaluation of right ventricular function in preterm infants with bronchopulmonary dysplasia

AIM

To evaluate right ventricular function in preterm infants with and without bronchopulmonary dysplasia.

METHODS

Eighty-nine preterm infants (<32 weeks) were divided into three groups: (1) no-bronchopulmonary dysplasia (n=32); (2) mild-bronchopulmonary dysplasia (n=35); (3) severe-bronchopulmonary dysplasia (n=15). Right ventricular echocardiographic parameters included the following: (1) pulsed-wave Doppler through the tricuspid valve (E/A ratio), pulmonary artery acceleration time, right ventricular ejection time, right ventricular velocity-time integral; (2) tissue Doppler measurements of myocardial velocities and atrioventricular conduction times; (3) pulsed-wave Doppler and tissue Doppler evaluation of myocardial performance index and E/E' ratio; and (4) M-mode detection of right ventricular end-diastolic wall diameter.

RESULTS

The severe-bronchopulmonary dysplasia group had higher mean right ventricular myocardial performance index (on the 28th day of life by pulsed-wave Doppler) than the no-bronchopulmonary dysplasia (P=.014) or mild-bronchopulmonary dysplasia (P=.031) groups; no differences were found between no-bronchopulmonary dysplasia and mild-bronchopulmonary dysplasia groups (P=.919). A reduction in right ventricular myocardial performance index at later time points was observed in all three groups (P<.05). We found no differences between preterm infants with differing bronchopulmonary dysplasia severity in other right ventricular echocardiographic parameters.

CONCLUSION

Right ventricular myocardial performance index measured by pulsed-wave Doppler indicates impaired right ventricular function in preterm infants with severe bronchopulmonary dysplasia.

Time dependent impact of perinatal hypoxia on growth hormone, insulin-like growth factor 1 and insulin-like growth factor binding protein-3

Hypoxic-ischemia (HI) is a widely used animal model to mimic the preterm or perinatal sublethal hypoxia, including hypoxic-ischemic encephalopathy. It causes diffuse neurodegeneration in the brain and results in mental retardation, hyperactivity, cerebral palsy, epilepsy and neuroendocrine disturbances. Herein, we examined acute and subacute correlations between neuronal degeneration and serum growth factor changes, including growth hormone (GH), insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) after hypoxic-ischemia (HI) in neonatal rats. In the acute phase of hypoxia, brain volume was increased significantly as compared with control animals, which was associated with reduced GH and IGF-1 secretions. Reduced neuronal survival and increased DNA fragmentation were also noticed in these animals. However, in the subacute phase of hypoxia, neuronal survival and brain volume were significantly decreased, accompanied by increased apoptotic cell death in the hippocampus and cortex. Serum GH, IGF-1, and IGFBP-3 levels were significantly reduced in the subacute phase of HI. Significant retardation in the brain and body development were noted in the subacute phase of hypoxia. Here, we provide evidence that serum levels of growth-hormone and factors were decreased in the acute and subacute phase of hypoxia, which was associated with increased DNA fragmentation and decreased neuronal survival.

The effects of preterm birth and its antecedents on the cardiovascular system

INTRODUCTION

Preterm birth occurs in approximately 10% of all births worldwide. It prematurely exposes the developing cardiovascular system to the hemodynamic transition that occurs at birth and to the subsequent functional demands of life ex utero. This review describes the current knowledge of the effects of preterm birth, and some of its common antecedents (chorioamnionitis, intra-uterine growth restriction, and maternal antenatal corticosteroid administration), on the structure of the myocardium.

MATERIAL AND METHODS

A thorough literature search was conducted for articles relating to how preterm birth, and its antecedents, affect development of the heart. Given that sheep are an excellent model for the studies of cardiac development, this review has focused on experimental studies in sheep as well as clinical findings.

RESULTS

Our review of the literature demonstrates that individuals born preterm are at an increased risk of cardiovascular disease later in life, including increased mean arterial pressure, abnormally shaped and sub-optimally performing hearts and changes in the vasculature. The review highlights how antenatal corticosteroids, intra-uterine growth restriction, and exposure to chorioamnionitis also have the potential to impact cardiac growth in the preterm newborn.

CONCLUSIONS

Preterm birth and its common antecedents (antenatal corticosteroids, intra-uterine growth restriction, and chorioamnionitis) have the potential to adversely impact cardiac structure immediately following birth and in later life.

Cardiovascular and metabolic risk markers are related to parasympathetic indices in pre-pubertal adolescents

OBJECTIVE

To analyse the relationship between different heart rate variability indices, resting heart rate, and cardiovascular markers in adolescents.

METHODS

A cross-sectional study was carried out with information from an ongoing cohort study. The sample was composed of 99 adolescents who complied with the following inclusion criteria: aged between 11 and 14 years; enrolled in a school unit of elementary education; absence of any known diseases; no drug consumption; and a formal consent signed by the parents or legal guardians. Weight, height, heart rate variability, lipid profile, inflammatory markers, blood pressure, resting heart rate, intima-media thickness, blood flow, and trunk fatness were measured. Partial correlation and linear regression (expressed by β and 95% confidence intervals [95%CI]) analyses were used to analyse the relationships between the variables.

RESULTS

In the linear regression analysis, even after adjustments for sex, age, trunk fatness, and somatic maturation, parasympathetic activity presented significant correlations with maximum carotid artery blood flow (β=-0.111 [95%CI=-0.216; -0.007]), systolic blood pressure (β=-0.319 [95%CI=-0.638; -0.001]), and resting heat rate (β=-0.005 [95%CI=-0.009; -0.002]).

CONCLUSION

Parasympathetic activity at rest is inversely related to maximum and minimum blood flow, triacylglycerol levels, and systolic blood pressure. These findings suggest that heart rate variability has the potential to discriminate pre-pubertal adolescents at increased risk.

Utility of Targeted Neonatal Echocardiography in the Management of Neonatal Illness

OBJECTIVES

To describe the impact of targeted neonatal echocardiography on management of neonatal illness in a tertiary perinatal center neonatal intensive care unit (NICU).

METHODS

We conducted a retrospective analysis of consecutive targeted neonatal echocardiographic studies that were performed over an 18-month period in a regional perinatal center NICU in Canada. All studies were performed with a cardiovascular ultrasound machine and transducer and read on a workstation with storage and analysis software. Reporting was done on a standardized document, and any management change resulting from targeted neonatal echocardiography was documented.

RESULTS

A total of 303 consecutive targeted neonatal echocardiographic studies were performed on 129 neonates. The mean gestational age ± SD was 27.8 ± 4.3 weeks (range, 23-41 weeks), and the mean birth weight ± SD was 1196 ± 197 g (range, 490- 4500 g). The median number of studies per neonate was 2 (range, 1-8), with most repeated studies for a patent ductus arteriosus (PDA). The most common indication for echocardiography was assessment of a PDA (52.1%), followed by early global hemodynamic assessment of very low birth weight (16.2%) and pulmonary hypertension (12.2%). Of the 303 studies, 126 (41.5%) resulted in management changes. The contribution to management was significantly related to the timing of echocardiography. Around half of the echocardiographic examinations during first the week of life resulted in management changes, compared to 22% of studies after 1 week of age (P = .002). Patent ductus arteriosus management accounted for almost half of the interventions.

CONCLUSIONS

Targeted neonatal echocardiography is a valuable tool in the NICU and can contribute substantially to hemodynamic management in the first week of life, PDA management in the first 2 weeks of life, and cases of hypotension or shock at any time during the hospital stay.

Treatment of premature infants with pulmonary hypertension and right ventricular dysfunction with milrinone: a case series

OBJECTIVE

Milrinone has been proposed as an effective treatment for pulmonary hypertension (PH) and right ventricular (RV) dysfunction. We aimed to determine the effect of milrinone therapy on clinical and echocardiography parameters of PH in preterm infants with elevated pulmonary pressures.

STUDY DESIGN

A retrospective case review was conducted on infants <32 weeks gestation who received milrinone for the treatment of PH and reduced RV function. Echocardiographic data were collected before and after treatment with milrinone, and serial clinical parameters were recorded over a 72h  period.

RESULT

Seven infants met the inclusion criteria with a median gestation and birth weight of 27.3 weeks and 1140 g, respectively. Four infants had a diagnosis of pulmonary hypoplasia with PH, and three infants were recipients in twin-to-twin transfusion syndrome who also developed PH. Nitric oxide was used in six infants before commencement of milrinone. Milrinone was commenced at a dose of 0.33 μg kg(-1) min(-1) to 0.5 μg kg(-1) min(-1) and continued for a median duration of 70 h. Use of milrinone was associated with a fall in oxygenation index and inhaled nitric oxide dose. Following an initial fall in blood pressure over the first 6 h, there was an increase in blood pressure over the subsequent 72 h. Echocardiographic data demonstrated an increase in indicators of myocardial performance and PH. One infant died before discharge.

CONCLUSION

This case series suggests that milrinone may be a useful therapy for premature infants with echocardiography findings of PH and/or RH dysfunction. This data support the need for a randomised control trial to confirm its efficacy.

Serial assessment of right ventricular function using tissue Doppler imaging in preterm infants within 7 days of life

BACKGROUND

We aimed to evaluate right ventricular (RV) function longitudinally using tissue Doppler imaging (TDI) echocardiography in preterm infants.

METHODS

We selected 101 very-low-birth-weight (VLBW) infants for the study. Echocardiographic examinations including TDI were performed serially within 7days of life. Pulsed-Doppler TDI waveforms were recorded at the tricuspid valve annulus, and peak systolic velocities (Sa), early diastolic velocities (Ea), and late diastolic velocities (Aa) were measured.

RESULTS

Sa, Ea and Aa were all reduced significantly from 3h to 12h, and then increased gradually thereafter. These three velocities also increased with gestational age in the early neonatal period. The ratio of Ea to Aa (Ea/Aa) did not change significantly within the first week of life. The ratio of E to Ea (E/Ea) in VLBW infants also seemed to remain stable from birth to day 7. The values of Sa appeared to be associated with cardiac output in the early neonatal period. Both Sa and Aa in intubated infants were significantly higher than in non-intubated infants.

CONCLUSION

RV TDI velocities of preterm infants in the early neonatal period are influenced by gestational age, postnatal age, and respiratory status, although the RV E/Ea ratio appears to be almost stable throughout the neonatal period. Our findings may provide some basis for assessment of RV function in critically ill preterm infants.

Assessment of myocardial function in preterm infants with patent ductus arteriosus using tissue Doppler imaging

OBJECTIVE

To assess myocardial function in preterm infants with different degrees of ductal patency in the first week of life using tissue Doppler imaging.

STUDY DESIGN

Infants <30 weeks of gestation underwent echocardiography on day 3. A total of 72 infants were recruited into the study and categorised into three groups (i) haemodyamically significant ductus arteriosus, (ii) patent ductus arteriosus and (iii) no patent ductus arteriosus. Those with haemodynamically significant ductus arteriosus were treated with indometacin and echocardiography was repeated after 48-72 hours following treatment. Peak systolic and diastolic myocardial velocities were obtained using tissue Doppler imaging, and myocardial performance index was calculated.

RESULTS

Initial myocardial velocities were significantly lower and myocardial performance index significantly higher in the haemodynamically significant ductus arteriosus group compared with other groups. For the haemodynamically significant ductus arteriosus group, post-treatment myocardial velocities were higher and myocardial performance index lower than pre-treatment.

CONCLUSION

Preterm infants with haemodynamically significant ductus arteriosus had lower myocardial velocities and higher myocardial performance index, suggesting relative systolic and diastolic myocardial dysfunction. Babies whose patent ductus arteriosus remained open despite indometacin had lower pre-treatment myocardial velocities and higher myocardial performance index than those babies whose patent ductus arteriosus closed, suggesting worse myocardial function in this group. Measurement of myocardial function using tissue Doppler imaging in preterm infants is feasible and may prove to be helpful in the management of babies with patent ductus arteriosus.

Longitudinal systolic left ventricular function in preterm and term neonates: reference values of the mitral annular plane systolic excursion (MAPSE) and calculation of z-scores

The mitral annular plane systolic excursion (MAPSE) is a quick and reliable echocardiographic tool for assessing longitudinal left ventricular (LV) systolic function in children and adults. Because this parameter is affected by the LV longitudinal dimension, pediatric and adult normal values are not suitable for preterm and term neonates. A prospective study investigated a large group of preterm and term neonates [gestational age (GA), 26/0-6 to 40/0-6; birth weight (BW), 670-4,140 g]. The growth- and BW-related changes in MAPSE were determined to establish normal z-score values for preterm and term neonates. The MAPSE ranged from a mean of 0.36 ± 0.05 cm in preterm neonates with a GA of 26/0-6 to 0.56 ± 0.08 cm in term neonates with a GA of 40/0-6. The findings showed MAPSE, GA, and BW to be moderately correlated. Pearson's correlation coefficient was 0.56 for GA (MAPSE; p < 0.001) and 0.58 for BW (MAPSE; p < 0.001). The normal MAPSE values did not differ significantly between females and males (p = 0.946). The absolute values and z-scores of normal MAPSE values in healthy preterm and term neonates within the first 48 h of life were calculated, and percentile charts were established. Determination of LV function using MAPSE might be useful for vulnerable infants for whom a prolonged examination is inappropriate and for neonates with suboptimal visualization of the endocardium.

Evolution of left ventricular function in the preterm infant

BACKGROUND

The aim of this study was to evaluate left ventricular function in preterm infants from 28 days to near term using echocardiography.

METHODS

Thirty clinically stable preterm infants delivered at <30 weeks' gestational age were prospectively enrolled. At 28 days, conventional, tissue Doppler, and speckle-tracking echocardiography evaluations of left ventricular function were performed, with comparison made to findings in 30 healthy term infants of similar postnatal age. Sixteen preterm infants underwent repeat examinations near term.

RESULTS

Compared with controls, preterm infants at 28 days had decreased peak mitral valve (MV) E-wave velocities (P < .01), E/A ratios (P < .0001), annular e' velocities (P < .0001), and e'/a' ratios (P < .0001); increased MV E/e' ratios (P < .01); and lower basal circumferential early diastolic and higher late diastolic strain rates. No significant differences were found in fractional shortening, ejection fraction, and longitudinal or circumferential strain and strain rate between preterm infants and controls. Although preterm infants at 28 days had higher heart rates compared with controls (161 ± 15 vs 142 ± 16 beats/min), no significant correlations existed between heart rate and MV E, E/A ratio, e', e'/a' ratio, and E/e' ratio. Near term, the differences in diastolic function persisted, including decreased MV e'/a' ratio (P < .05), increased E/e' ratio (P < .01), and increased late diastolic strain rate.

CONCLUSIONS

Clinically stable preterm infants have normal left ventricular systolic function but altered diastolic function, with greater dependence on atrial contraction, the latter of which persists despite nearing term. These findings may be relevant to the management of preterm infants and may relate to the longer term myocardial dysfunction observed in affected adults.

Heterogeneity of ventricular repolarization in newborns with intrauterine growth restriction

BACKGROUND

Intrauterine growth restriction (IUGR) is associated with structural and functional cardiac alterations but the electrophysiological consequences of these disturbances remain unknown.

AIMS

To explore the distribution of ventricular repolarization and its relation to myocardial mechanics in newborns with IUGR. STUDY DESIGN, SUBJECTS AND OUTCOME MEASUREMENTS: Conventional and tissue Doppler echocardiographic data, and electrocardiographic parameters used to describe the distribution of ventricular repolarization (dispersion of QT [QTd] and JT [JTd]), were obtained on the second (D2) and fifth (D5) postnatal day and compared between 25 IUGR newborns and 25 matched-for-gestational age controls.

RESULTS

IUGR was associated with relative interventricular septum hypertrophy, increased left ventricular (LV) E/E' ratio and higher LV myocardial performance index (MPI). On both study days, the IUGR infants presented higher QTd and JTd compared to controls (QTd-D2: 66±20 ms vs. 36±12 ms, P<0.001; JTd-D2: 54±13 ms vs. 34±9 ms, P<0.001; QTd-D5: 61±14 ms vs. 27±12 ms, P<0.001; JTd-D5: 54±13 ms vs. 27±9 ms, P<0.001). The association between QTd and LV E/E' (D2: regression coefficient beta 0.747, R(2) 0.585; D5: beta 0.843, R(2) 0.646) and QTd and MPI (D2: beta 0.680, R(2) 0.576; D5: beta 0.698, R(2) 0.650) was also significant (P<0.001 for all analyses).

CONCLUSIONS

Our findings suggest that IUGR is associated with electrophysiological remodeling of the neonatal heart, a process which is closely related to the underlying alterations in ventricular mechanics and might predispose to adverse electrophysiological events.

Myocardial function in term and preterm infants. Influence of heart size, gestational age and postnatal maturation

BACKGROUND

Sparse knowledge exists on the differences in cardiac function between term and preterm infants. This study examines the impact of heart size, gestational age and postnatal maturation on myocardial function.

AIM

To assess and compare serial echocardiographic indices of myocardial function in term and moderately preterm infants.

METHODS

Longitudinal, prospective, observational echocardiographic cohort study of 45 healthy term infants examined at day three and at 12-20weeks postnatal age and 53 moderately preterm infants (gestational age 31-35weeks) examined at day three and at term equivalent (4-10weeks postnatal age).

OUTCOMES

Primary: Systolic mitral and tricuspid annular plane excursions and annular peak systolic pulsed wave tissue Doppler (pwTDI) velocities. Secondary: Indices normalized for heart size.

RESULTS

On day three, all indices were higher in the term than in the preterm infants whereas normalized systolic pwTDI velocities were lower in the term infants and normalized excursions showed no difference. All indices increased with advanced postnatal age. The indices in term infants on day three were lower than in preterm infants at term equivalent, with and without normalization. After postnatal maturation in both groups, all indices were higher in the term group (except left pwTDI), whereas normalized indices showed no consistent pattern.

CONCLUSIONS

Myocardial function indices increased with gestational age at birth and more profoundly with postnatal maturation. Serial examinations of non-normalized and normalized myocardial function indices showed no sustained differences between the preterm and the term infants. Normalization by heart size may be of value when assessing myocardial function in infants.

Serial changes in myocardial function in preterm infants over a four week period: the effect of gestational age at birth

BACKGROUND

Myocardial performance is impaired in the first days of life in preterm infants but improves by day 5. Tissue Doppler imaging (TDI) is a novel and reliable means of assessing myocardial performance.

OBJECTIVE

To investigate myocardial performance using TDI and shortening fraction (SF) in preterm infants of different gestational age groups and serial changes in these parameters in first four weeks of life. Study design Infants less than 36 weeks of gestation were divided into group 1 (24-27 weeks, n=8), group 2 (28-31 weeks, n=12) and group 3 (32-35 weeks, n=13). Infants with severe congenital malformations, a hypoxic insult at birth, and those on inotropic support were excluded. Echocardiograms were performed at 36-48 hours, 2 weeks and 4 weeks of life. Left ventricular (LV) SF, systolic (S'), early diastolic (E') and late diastolic (A') TDI velocities were assessed. We analyzed the data using a repeated-measures ANOVA.

RESULTS

Thirty three infants underwent serial TDI and SF measurements. There was an increase in LV S' (p=.02) and E' (.01) velocities in group 2 , and in group 3 (p=.03 for S' and p=.04 for E'), but no significant increase in group 1 (p=.48 for S' and .32 for E'). At each study point, there was significant difference in myocardial performance between group 1 and 3 for each of the parameters (p<.05). There was no significant increase in SF over time in any of the groups.

CONCLUSION

We describe a serial increase in myocardial performance in infants of 28 weeks gestation and above. While there was no change in myocardial performance among the most extremely preterm infants, this may have been the result of small sample size of the group.

Neonatal cardiac dysfunction in intrauterine growth restriction

BACKGROUND

The early postnatal cardiovascular consequences of intrauterine growth restriction (IUGR) have not been completely elucidated. This study aimed to evaluate the effect of IUGR on neonatal myocardial function and cardiovascular adaptation to extrauterine life.

METHODS

Conventional and tissue Doppler echocardiographic parameters were compared on the second and fifth postnatal day between 30 IUGR and 30 appropriate-for-gestational age (AGA) neonates.

RESULTS

IUGR neonates presented relative interventricular septum (IVS) hypertrophy (IVS to left ventricular (LV) posterior wall diastolic ratio: median IUGR-AGA difference of 0.05 (interquartile range: 0.04-0.06); P = 0.020), relative LV dilatation (wall thickness to end-diastolic LV dimension difference of 0.12 (0.06-0.16); P = 0.012), and increased left myocardial performance index (MPI difference of 0.19 (0.05-0.28); P = 0.012). Repeated measurements ANOVA revealed a different pattern of change in LV stroke volume (LVSV; P < 0.001), LV cardiac output (LVCO; P < 0.001), MPI (P < 0.001), and heart rate (HR; P = 0.025) between AGA and IUGR infants. From the second to the fifth postnatal day, AGA neonates presented a decrease in MPI and HR with an increase in LVSV and LVCO. IUGR neonates failed to achieve similar changes in MPI, HR, and LVSV, whereas their LVCO decreased.

CONCLUSION

IUGR neonates present changes in cardiac morphology and subclinical myocardial dysfunction, which may result in an altered pattern of cardiovascular adaptation to extrauterine life.

Glucocorticoids and foetal heart maturation; implications for prematurity and foetal programming

Glucocorticoids are steroid hormones, essential in mammals to prepare for life after birth. Blood levels of glucocorticoids (cortisol in most mammals including humans; corticosterone in rats and mice) rise dramatically shortly before birth. This is mimicked clinically in the routine administration of synthetic glucocorticoids to pregnant women threatened by a preterm birth or to preterm infants to improve neonatal survival. Whilst effects on lung are well documented and essential for postnatal survival, those on heart are less well known. In this study, we review recent evidence for a crucial role of glucocorticoids in late gestational heart maturation. Either insufficient or excessive glucocorticoid exposure before birth may alter the normal glucocorticoid-regulated trajectory of heart maturation with potential life-long consequences.

Tissue Doppler imaging in very preterm infants during the first 24 h of life: an observational study

BACKGROUND

Very preterm newborn infants often need cardiovascular support. More knowledge about myocardial function and factors that influence the immature myocardium may be helpful for optimising cardiovascular support in these infants.

OBJECTIVE

Serial assessment of global myocardial function by means of colour tissue Doppler imaging (cTDI) in very and extremely preterm infants during the first 24 h of life.

STUDY DESIGN

One-centre, prospective, observational longitudinal cohort study in a third level Neonatal Intensive Care Unit. Sixty-five infants with median (range) gestational age (GA) 27 (24-31) weeks and birth weight (BW) 1049 (484-1620) g underwent echocardiographic examinations including cTDI at 5, 12 and 24 h after birth.

MAIN OUTCOME MEASURES

Peak systolic and peak diastolic annular velocity and peak annular displacement of the left and right ventricle.

RESULTS

There was a significant reduction in systolic and diastolic velocities and displacement of both ventricles from 5 to 12 h age. From 12 to 24 h, there was a non-significant increase in myocardial velocities and displacement. At 5 h, babies with haemodynamically significant patent ductus arteriosus (PDA) had significantly higher systolic and diastolic velocities in both ventricles than those with non-significant PDA.

CONCLUSIONS

Myocardial tissue velocities decrease significantly from 5 to 12 h after birth in very preterm infants. Further studies are needed to confirm these results and to determine their clinical implications.