|Year : 2022 | Volume
| Issue : 1 | Page : 45-50
A study on normal reference values of echocardiographic chamber dimensions in newborn infants from Eastern India – A pilot study
Swapan Kumar Halder1, Samir Kumar Roy1, Anindya Mukherjee1, Dibbendhu Khanra2, Malyaban Das1, Biaus Samanta1, Soumyojit Saha3, Manoranjan Mandal1
1 Department of Cardiology, NRS Medical College, Kolkata, West Bengal, India
2 Department of Electrophysiology and Devices, Electrophysiology and Devices, Royal Wolverhampton NHS Trust, England, UK
3 Department of Cardiology, Narayana Multispeciality Hospital, Howrah, West Bengal, India
|Date of Submission||01-Jan-2022|
|Date of Acceptance||25-Jan-2022|
|Date of Web Publication||13-Apr-2022|
Dr. Anindya Mukherjee
Department of Cardiology, NRS Medical College, 138, A.J.C. Bose Road, Kolkata - 700 014, West Bengal
Source of Support: None, Conflict of Interest: None
Introduction: Echocardiography has been an integral part of neonatal care since the 1990s and the application of this technology is increasing ever since. It is already known that differences in weight, age, and race significantly affect the normal heart dimensions. Therefore, establishing the normative values for cardiac dimensions among Indian healthy newborn infants is of paramount importance. In this study, we report the normal reference values of echocardiographic chamber dimensions of newborn infants from Eastern India.
Methodology: One hundred healthy newborn infants were included in this cross-sectional, observational, single hospital-based pilot study. A single experienced cardiologist performed the transthoracic echocardiographic studies on the participants in supine position in their respective bassinets. No sedation was used. The parameters were distributed according to body weight and in percentiles.
Results: Participants were categorized according to their body weight into three groups: 2–2.4 kg, 2.5–2.9 kg, and 3–3.5 kg. Each group comprises 7, 50, and 43 newborns, respectively. The left ventricular end-diastolic dimension and left ventricular end-systolic dimension showed incremental trends across body weight.
Conclusion: This study shows the difference of cardiac dimensions in Indian newborn infants from Western data. This is the first study presenting the normative reference ranges and percentiles of echocardiographic parameters in Indian newborn infants which needs confirmation with larger multicenter studies.
Keywords: Echocardiography, newborn infants, percentiles, pilot study, reference range
|How to cite this article:|
Halder SK, Roy SK, Mukherjee A, Khanra D, Das M, Samanta B, Saha S, Mandal M. A study on normal reference values of echocardiographic chamber dimensions in newborn infants from Eastern India – A pilot study. Heart India 2022;10:45-50
|How to cite this URL:|
Halder SK, Roy SK, Mukherjee A, Khanra D, Das M, Samanta B, Saha S, Mandal M. A study on normal reference values of echocardiographic chamber dimensions in newborn infants from Eastern India – A pilot study. Heart India [serial online] 2022 [cited 2022 May 16];10:45-50. Available from: https://www.heartindia.net/text.asp?2022/10/1/45/343062
| Introduction|| |
Echocardiography has been an integral part of neonatal care since the 1990s and the application of this technology is increasing ever since.,, “Functional,” “point of care,” “target,” or “focus” echocardiography have become an invaluable tool in neonatal and pediatric intensive care settings. The concept of “neonatologist-performed echocardiography” has developed for improved cardiorespiratory care of newborn. Several small studies have suggested normative data related to cardiac chambers in infants and newborn over the past 50 years but none has been reported from the Indian subcontinent and no clear guidelines exist unlike adults. A prior study by Mukherjee et al. showed that echocardiographic chamber dimensions among normal Indian participants not only varied from the Western data but also varied among different parts of the country. It is already known that differences in weight, age, and race significantly affect the normal heart dimensions.,, Therefore, establishing the normative values for cardiac dimensions among Indian healthy newborn infants is of paramount importance. In this study, we report the normal reference values of echocardiographic chamber dimensions of newborn infants from Eastern India.
| Methodology|| |
One hundred healthy newborn infants (from 24 h after birth up to 7 days) delivered at term by vaginal delivery or cesarean section from February 2020, to January 2021, were included in this cross-sectional, observational, single hospital-based pilot study. The participant's recruitment process has been depicted in [Figure 1]. The ethical standards of the responsible committee on human experimentation (institutional and national) and the Helsinki Declaration of 1964 and later revisions were followed in all steps of research. Parents of all the participants gave informed consent for the study. The Institutional Review Board approved the study.
A single experienced cardiologist performed the transthoracic echocardiographic studies using a Vivid S5 machine with a M7S matrix array probe with a frequency range from 5.7 to 7.2 MHz (GE Vingmed, Horten, Norway). Machine-integrated Electrocardiography (ECG) recording was performed simultaneously. Each measurement was taken three times and averaged.
The echocardiography was performed on the participants in supine position in his/her respective bassinet., No sedation was used, although a pacifier nipple was sometimes required to keep the neonate quiet and at rest.,
The left atrial (LA) anteroposterior diameters were measured on the parasternal long axis view at end-systole.,, Aortic root diameters (Ao) (at maximal diameter of sinus of Valsalva) were measured from the same view. Two-dimensional-guided parasternal short axis view was used to measure the thickness of the interventricular septum at end-diastole, left ventricular dimension at end-diastole (LVEdD), left ventricular dimension at end-systole (LVEsD), and left ventricular posterior wall thickness at end-diastole from leading edge of the septal endocardium to the leading edge of the posterior wall endocardium as per the recent guidelines.,,, Similar leading edge to leading edge convention was used for LA and the right ventricular outflow dimension in end-diastole (RVEdD) measurement. The right ventricular anterior wall thickness at end-diastole and RVEdD at tricuspid annulus were measured in 2-D apical 4-chamber view. Main pulmonary artery diameter (PA) at the level of semilunar valve was measured from parasternal short-axis view in systole. LV ejection fraction (LVEF) and fractional shortening were measured using the biplane Simpson rule.,
Echocardiographic dimensions were evaluated using bodyweight since body surface area changed minimally in this population.
The mean ± standard deviation (SD) rule was followed to propose normal echocardiographic reference values in this study. This is based on the assumption that 95% of values of a reference group is in this range, and the sample value can be greater than the upper limit or lesser than the lower limit in 2.5% of the time, respectively, whatever might be the distribution of these values.
For statistical analysis, data were analyzed by SPSS (version 24.0; SPSS Inc., Chicago, IL, USA) and GraphPad Prism version 5. Summarization of data was done as mean and SD for numerical variables and count and percentages for categorical variables. Percentile-wise distribution of data was performed.
| Results|| |
Participants were categorized according to their body weight into three groups: 2–2.4 kg, 2.5–2.9 kg, and 3–3.5 kg. Each group comprises 7, 50, and 43 newborns, respectively.
Means of chamber dimensions
The mean ± SD values of each of 11 cardiac dimensions as mentioned above for newborns in relation to body weight were calculated as shown in [Table 1]. Parameters except mean LVEdD and LVEsD did not show any incremental trend with increase of body weight.
|Table 1: The mean values of echocardiographic chamber dimensions according to body weight in Eastern Indian newborn infants|
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Normal reference range
Normal reference ranges of echocardiographic chamber dimensions are depicted in [Table 2]. As evident from the mean values, only LVEdD and LVEsD showed incremental values of upper normal reference limit and lower normal reference limit with increase of body weight. Other parameters did not show any clear trend with increasing body weight.
|Table 2: Normal reference ranges of echocardiographic chamber dimensions in Eastern Indian newborn infants|
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Percentiles of the values of echocardiographic measurements
Percentile values (5th, 10th, 25th, 50th, 75th, 90th, and 95th centiles) for each of the cardiac dimensions were calculated and shown in [Table 3].
|Table 3: Percentiles of the values of echocardiographic measurements in Eastern Indian newborn infants|
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Distribution of echocardiographic parameters according to body weight
[Figure 2] is a composite of scatterplots showing the spread of the various echocardiographic parameters across body weight. As evident from the earlier results, only the values of LVEdD and LVEsD show some positive relationship with increasing body weight.
|Figure 2: Distribution of echocardiographic parameters according to body weight. Ao: Aortic root dimension, mm, IVSd: Septal thickness at end-diastole, mm, LAd: Left atrial anteroposterior dimension, mm, LVEdD: Left ventricular end-diastolic dimension, mm, LVEF: Left ventricular ejection fraction, %, LVEsD: left ventricular end-systolic dimension, mm, LVFS: Left ventricular fractional shortening, %, LVPWd: Posterior wall thickness at end-diastole, mm, PA: Main pulmonary artery diameter, mm, RVAWd: Right ventricular anterior wall thickness at end-diastole, mm, RVEdD: Right ventricle outflow diameter at end-diastole, mm|
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| Discussion|| |
Heterogeneity of echocardiographic parameters
The wide range of changes during normal development of the cardiac structures requires a large study group for accurate data on normal values, even when centile charts are used., Studies from different parts of the world have shown similarity as well as disparity of echocardiographic parameters among neonates., In addition, a study conducted by DerSimonian and Levine showed that data obtained from multiple small population studies and combined by meta-analysis has a drawback in that they are overtly affected by the heterogeneity of the populations examined. With the heterogeneity of data from different parts of the world in the background, Bansal et al. conducted a pilot study to assess the echocardiographic parameters in northern Indian adults. A recent study from our center confirmed the regional heterogenicity of echocardiographic parameters in young adults. Therefore, the need for regional references of the basic echocardiographic parameters in newborn infants is paramount. To the best of our knowledge, there are no studies that evaluated healthy term Indian neonates to develop centile charts.
Gender appeared only a significant determinant for LVEdD among children in a Dutch study. If gender would have been an important determinant, it would have been significant for all cardiac dimensions since the expectation has to be that a larger heart needs thicker walls because of Laplace's law. Hence, if boys would have larger LV dimensions, it would be expected that the walls are thicker as well, which was not observed. Therefore, it was chosen to establish new reference ranges of cardiac dimensions independent of gender. This is in accordance with the results of other studies.,,,,
Studies on echocardiographic parameters of newborn infants
Only a handful number of studies from different parts of the world report normative reference ranges of echocardiographic parameters in the sizeable population of newborn infants.,,, The studies by Kampmann et al. and Güzeltaş et al. followed the old American Society of Echocardiography recommendations in measuring the echocardiographic parameters, whereas our study followed methods in measuring the chamber dimensions in accordance with the current guidelines.,
Echocardiographic dimensions and body weight
Güzeltaş et al. found that the right and left ventricular, LA and aortic dimensions increased linearly with body weight, while in our study, only LVEdD and LVEsD showed incremental trends with body weight.
Comparison of echocardiographic parameters across different studies
[Table 4] shows normal echocardiographic values in studies that include 100 or more healthy newborn infants. RVEdD, LVEdD, and LVEsD were lesser than the earlier studies which can be attributed to interobserver variability, regional, and ethnic differences.,,, Moreover, with time, the temporal and spatial resolution of echocardiographic scanners have improved yielding more exact measurements. Unlike in this study and that by Güzeltaş et al., where a single cardiologist performed all the procedures, measurements were recorded by several cardiologists in the earlier studies.,,, Lad and Ao had a similar range of measurements in our study and that by Güzeltaş et al., Kampmann et al. but lower than those by Solinger et al. and Hagan et al.,,, This difference can be due to the reasons already stated. The fact that the earlier studies were conducted even before the American Society of Echocardiography recommendations came into place should be taken into account.,, For example, the exterior dimension of the aorta was measured in the study by Solinger et al. LVEF found in our study was similar to the study by Güzeltaş et al.
|Table 4: Normal echocardiographic values in studies that include 100 or more healthy newborns|
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Omission of measurement of detailed right ventricular dimensions and function was a major drawback. Doppler parameters were not included in the study. This was a pilot study on only 100 newborn infants from a large volume tertiary care center of Eastern India and a larger sample size from various parts of the country is needed to confirm the findings. Like most studies, our study included body weights of 2–4.5 kg, but among the study population, no newborn infant was found to have body weight >3.5 kg. Hence, the direct comparison of parameters with other studies cannot be done. Last, interobserver variability remains a hindrance while comparing datasets from various parts of the world.
| Conclusion|| |
This study which included newborn infants from Eastern India reaffirms that Indian participants have smaller cardiac chamber diameters compared to the Western population. This is the first study presenting the normative reference ranges and percentiles of echocardiographic parameters in Indian newborn infants which needs confirmation with larger multicenter studies. The normal reference ranges and percentiles of echocardiographic measurements will be of immense value while treating a sick newborn or preparing Indian neonatal echocardiographic guidelines. This study will pave the way for further research on echocardiography of Indian newborn infants.
What is already known
Differences in weight, age, and race significantly affect the normal heart dimensions.
What this study adds
This is the first study presenting the normative reference ranges and percentiles of echocardiographic parameters in Indian newborn infants.
The study was approved by the institutional review board (as discussed in the methods section).
SKH, SR, SS: concept and design, acquisition of data and interpretation, critical review and final approval of the study; AM, DK, MD: concept and design, interpretation of data, drafting the article, critical review, and final approval of the study; MM, BS: concept and design, critical review, and final approval of the study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]