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Volume 4, Jan - Mar 2021
Research Article:
Author’s Affiliation:
1- Department of Medicine, Murshidabad Medical College Berhampore, West Bengal
Correspondence:
Dr. Sudipta Mondal, Email: sudiptamondalnrs@gmail.com
Received on: 16-Aug-2020
Accepted for Publication: 02-Jan-2021
Article No: 20816ldJ112054
PDF - Full Text
Abstract

Introduction: The echocardiograph is an essential tool for cardiac evaluation and progress in pediatric cardiology has made this investigation more inevitable than before. However, normal values in neonatal cardiology are yet to be established for the Indian subcontinent. 

Materials and Methods: We studied 99 healthy term infants, 0 – 7 days old in a tertiary center of Eastern India and documented the mean and standard deviation of 11 basic echocardiographic parameters for future reference. 

Conclusions: RVAWd, IVSd, LVEDd and LVEDs have significant correlation with infant body weight.

Keywords: Pediatric, neonates, echocardiography, nomograms

INTRODUCTION

A quantitative assessment of cardiac chambers, valves, and great vessels is often of critical importance in evaluating the severity of any congenital and acquired heart disease and in planning the most appropriate medical, interventional, and/or surgical treatment1-5. At present, pediatric echocardiographic nomograms of good quality exist for cardiac valves, pulmonary arteries, the aorta, and the aortic arch6-8. Pediatric nomograms for cardiac chamber diameters and areas, however, are still limited or even absent. For the left ventricle, there are sufficient nomograms for M-mode measurements, while normal values for left ventricular diameters and areas evaluated in two- and four-chamber views are almost absent. Furthermore, pediatric echocardiographic nomograms for right ventricular dimensions and atrial dimensions are also extremely limited9,10.

The primary aim of this work was to establish echocardiographic nomograms for ventricular and atrial dimensions in a population of healthy neonates.

MATERIALS AND METHODS

This cross sectional study was conducted at the Departments of Cardiology, Gynecology & Obstetrics and Pediatric Medicine, at Nil Ratan Sircar Medical College, Kolkata from February 2018 to December 2019. The study included 99 newborn infants who fulfilled the following:

  • Inclusion criteria:   Term infants, healthy on clinical examination
  • Exclusion criteria: Preterm, low birth weight, restlessness, any obvious illness on clinical    examination, and structural heart disease on echocardiography 

All the selected infants underwent a single echocardiographic examination within 7 days of birth, by a single examiner with appropriate transducers (7.5, 5.0 Hz) to define the cardiac    structures and obtain measurements on the following M mode echocardiographic parameters: 

  1. Right ventricular anterior wall thickness at end diastole (RVAWd)
  2. Right ventricular end diastolic dimension (RVDd) at tricuspid annulus.
  3. Thickness of the interventricular septum at end   diastole (IVSd)
  4. Left ventricular dimension at end diastole  (LVEDd)
  5. Left ventricular dimension at  end systole  (LVESd)
  6. Left ventricular posterior wall thickness at end  diastole (LVPWd)
  7. Pulmonary and aortic diameter at the level of semilunar valve (PAD and AOD)
  8. Left atrial diameter (LAD)
  9. From above dimensions, fractional shortening (FS) and ejection fraction (EF) was calculated 

All the newborns underwent echocardiographic examination in the supine position on the mother’s lap without any sedation. 2D and M mode echocardiography was performed in the standard precordial positions using a Siemens Accuson CV70 machine. Left ventricle (LV) dimensions were measured by 2D guided M mode echocardiogram of LV at papillary muscle level using parasternal long axis view. Measurements at end diastole were taken at the onset of QRS complex and the systolic internal diameter was measured at maximum excursion of ventricular septum which normally occurs before the maximal excursion of posterior wall. Internal diameter was taken from trailing edge of septum to leading edge of posterior wall (tissue blood interface). Septal thickness and posterior wall thickness was measured at the onset of QRS complex in parasternal long axis. Aortic root dimensions were obtained at the onset of QRS complex from leading age to leading edge of the aortic wall in parasternal long axis view. Left atrium (LA) dimensions were recorded at end-systole as the largest distance between posterior aortic wall and the center of the line denoting the posterior LA wall in parasternal long axis. Right ventricular end diastolic dimension was measured at tricuspid annulus in the apical four chamber view. Diameter of pulmonary artery at the annulus was measured in parasternal short axis view. From the above dimensions, fractional shortening (FS) and ejection fraction (EF) were calculated.

Data was collected in a systematic way and compiled. The cardiac dimensions as obtained from echocardiography were correlated with the body weight of the infant. Keeping in mind that the body surface area changes minimally with body weight in newborns, the former was not taken into separate consideration. Ethical approval was obtained from the Institutional Ethical committee. The unpaired t-test was used to compare the means and establish or refute the statistical significance of these differences, with p values. 

RESULTS AND ANALYSIS

 

We divided our cases into 3 groups based on body weight at the time of performing the echocardiographic assessment as follows:

  • Group A: Body weight Body weight : 2 – 2.4 kg
  • Group B: Body weight : 2.5-2.9 kg
  • Group C: Body weight : 3-3.4 kg

The mean body weight in the study population was 2.87 ± 0.28 kg with Groups A, B and C recording mean body weights of 2.31 ± 0.08, 2.74 ± 0.13 and 3.13 ± 0.14 kg respectively. The genders were equitably distributed with male: female ratio of 1.11 in the study cohort (Table 1).

 

Total (n = 99)

Group A (n= 8)

Group B (n = 49)

Group C (n = 42)

Male

52

2

22

28

Female

47

6

27

14

M : F

1.11

0.33

0.81

2.0

Mean BW (kg)

2.87 ± 0.28

2.31 ± 0.08

2.74 ± 0.13

3.13 ± 0.14


Table 1:           Gender distribution and body weight (BW) (mean ± SD)

Measurement of various wall thicknesses in diastole was comparable across the groups. The mean RVAWd was 3.39 ± 0.67 mm in the study with groups A, B and C having diastolic thickness of 3.64 ± 0.57, 3.58 ± 0.58 and 3.13 ± 0.71 mm respectively. Coming to the IVSd as measured in our study, Groups A, B and C revealed septal thickness of 3.51 ± 0.43, 3.59 ± 0.36 and 3.32 ± 0.55 mm respectively, with the overall mean in the study being 3.47± 0.47 mm. Similarly, the mean LVPWd in the study was 3.12 ± 0.49 mm, with the Groups A, B and C showing post wall thickness of 2.98 ± 0.13, 3.25 ± 0.51 and 3.05 ± 0.49 mm respectively. Statistically significant differences between mean values of RVAWd were observed between groups B and C, while the difference was significant between groups A and B as also between B and C when IVSd was considered (Table 2, Fig 1).

 

RVAWd (mm)

IVSd (mm)

LVPWd (mm)

Total (n = 99)

3.39 ± 0.67

3.47± 0.47

3.12 ± 0.49

Group A (n= 8)

3.64 ± 0.57

3.51 ± 0.43

2.98 ± 0.13

Group B (n = 49)

3.58 ± 0.58

3.59 ± 0.36

3.25 ± 0.51

Group C (n = 42)

3.13 ± 0.71

3.32 ± 0.55

3.05 ± 0.49

A, B

Unpaired t, df

1.1232,

55

14.7565,

55

1.4791,

55

p value

0.2662

0.0001

0.1448

B, C

Unpaired t, df

3.3273,

89

2.8069,

89

1.8989,

89

p value

0.0013

0.0061

0.0608

A, C

Unpaired t, df

1.9278,

55

0.9220,

48

0.3983,

48

p value

0.0590

0.3611

0.6922


Table 2:           Subgroup analysis of RVAWd (right ventricular anterior wall diastole), IVSd (intraventricular septum thickness in diastole) and LVPWd (left ventricular posterior wall thickness in diastole) (mean ± SD)


Fig 1:   Distribution of mean BW (body weight, in kg), RVAWd (right ventricular anterior wall diastole), IVSd (intraventricular septum thickness in diastole) and LVPWd (left ventricular posterior wall thickness in diastole), in mm.

Subsequently, we analyzed the data for cavity size in our study population. The mean RVDd in the study was 10.96 ± 1.19 mm while this value was 11.04 ± 1.04, 11.12 ± 1.25 and 10.75 ± 1.13 mm in the Groups A, B and C respectively. LVEDd and LVEDs was 14.95 ± 1.68 and 9.76 ± 1.65 mm in the study, 13.06 ± 1.23 and 8.09 ± 1.12 mm in Group A, 14.9 ± 1.83 and 9.53 ± 1.74 mm in Group B, and 15.37 ± 1.3 and 10.34 ± 1.32 mm in Group C. A rising trend with increasing body weight was evident in these LV measurements. However, the analysis of LAD in study population and Groups A, B and C revealed values of 10.09 ± 1.47, 9.5 ± 0.76, 10.38 ± 1.41 and 9.86 ± 1.59 mm respectively, defying any corroboration with body weight. Statistically different mean values were observed for LVEDd between Groups A and B and between A and C.  Considering LVESd, the means were statistically different between Groups A and B, B and C and between A and C (Table 3, Fig 2).

Further, the pulmonary and aortic valve diameters at the level of the semilunar valves were analyzed. The mean PAD was 8.09 ± 1.31, 8.15 ± 0.57, 8.17 ± 1.37 and 7.99 ± 1.34 mm for the study population and Groups A, B and C respectively. Similarly, the mean AOD was 8.22 ± 1.01, 8.26 ± 0.67, 8.36 ± 1.13 and 8.04 ± 0.90 mm for the study population and Groups A, B and C respectively. Neither of these parameters had any correlation with the body weight. The mean FS was 37.14 ± 4.14%, 38 ± 6.16%, 37.65 ± 4.65% and 36.38 ± 2.84% and the mean EF was 71.21 ± 5.37%, 71.63 ± 7.96%, 71.65 ± 5.92% and 70.62 ± 4.04% for the study population and

 

RVDd (mm)

LVEDd (mm)

LVESd (mm)

LAD (mm)

Total (n = 99)

10.96 ± 1.19

14.95 ± 1.68

9.76 ± 1.65

10.09 ± 1.47

Group A (n= 8)

11.04 ± 1.04

13.06 ± 1.23

8.09 ± 1.12

9.5 ± 0.76

Group B (n = 49)

11.12 ± 1.25

14.9 ± 1.83

9.53 ± 1.74

10.38 ± 1.41

Group C (n = 42)

10.75 ± 1.13

15.37 ± 1.3

10.34 ± 1.32

9.86 ± 1.59

A, B

Unpaired t, df

0.1712,

55

2.7339,

55

2.2560,

55

1.7160,

55

p value

0.8647

0.0084

0.0281

0.0918

B, C

Unpaired t, df

1.4709,

89

1.3903,

89

2.4683,

89

1.6534,

89

p value

0.1448

0.1679

0.0155

0.1018

A, C

Unpaired t, df

0.6728,

48

4.6419,

48

4.5118,

48

0.6230,

48

p value

0.5043

0.0001

0.0001

0.5362

 

Table 3:              Subgroup analysis of RVDd (right ventricular diameter in diastole), LVEDd (left ventricular end diastolic diameter), LVESd (left ventricular end systolic diameter) and LAD (left atrial diameter) (mean ± SD)


Fig 2:   Distribution of mean RVDd (right ventricular diameter in diastole), LVEDd (left ventricular end diastolic diameter), LVESd (left ventricular end systolic diameter) and LAD (left atrial diameter), in mm.

Groups A, B and C respectively (Table 4, Fig 3 and 4). The FS appeared to have an inverse correlation with body weight, but no such trend was evident when analyzing the EF. The mean values of PAD, AOD, FS and EF were not statistically different when sub-group analysis was performed with unpaired t test.

 

PAD (mm)

AOD (mm)

FS (%)

EF (%)

Total (n = 99)

8.09 ± 1.31

8.22 ± 1.01

37.14 ± 4.14

71.21 ± 5.37

Group A (n= 8)

8.15 ± 0.57

8.26 ± 0.67

38 ± 6.16

71.63 ± 7.96

Group B (n = 49)

8.17 ± 1.37

8.36 ± 1.13

37.65 ± 4.65

71.65 ± 5.92

Group C (n = 42)

7.99 ± 1.34

8.04 ± 0.90

36.38 ± 2.84

70.62 ± 4.04

A, B

Unpaired t, df

0.0405,

55

0.2423,

55

0.1885,

55

0.0084,

55

p value

0.9679

0.8095

0.8511

0.9933

B, C

Unpaired t, df

0.6311,

89

1.4768,

89

1.5402,

89

0.9529,

89

p value

0.5296

0.1433

0.1271

0.3432

A, C

Unpaired t, df

0.3299,

48

0.6553,

48

1.1915,

48

0.5438,

48

p value

0.7429

0.5154

0.2393

0.5891


Table 4: Subgroup analysis of PAD (pulmonary artery diameter), AOD (aortic root diameter), FS (fractional shortening) and EF (ejection fraction) (mean
± SD)


Fig 3:   Distribution of mean PAD (pulmonary artery diameter) and AOD (aortic root diameter), in mm.


Fig 4:   Distribution of mean FS (fractional shortening) and EF (ejection fraction).

The distribution of the study parameters were analyzed as percentiles and tabulated. The percentile values (5th, 10th, 25th, 50th, 75th, 90th, and 95th centiles) for all echocardiographic parameters documented in this study were documented for future reference (Table 5).

 

 

Percentiles

 

5th

10th

25th

50th

75th

90th

95th

RVAWd (mm)

2.205

2.410

3.000

3.400

3.800

4.200

4.490

RVDd (mm)

9.000

9.200

9.850

11.200

11.975

12.400

12.700

IVSd (mm)

2.400

3.000

3.225

3.500

3.800

4.100

4.100

LVEDd (mm)

11.310

13.310

14.100

14.850

16.000

17.090

17.785

LVESd (mm)

7.105

7.330

8.500

9.550

11.100

11.790

12.795

LVPWd (mm)

2.40

2.42

2.80

3.00

3.48

3.80

4.10

PAD (mm)

5.820

6.400

7.200

8.000

9.100

9.400

9.690

AOD (mm)

6.500

7.100

7.350

8.200

9.000

9.300

10.295

LAD (mm)

7.330

8.400

9.200

10.100

11.000

11.790

12.000

FS (%)

31.00

32.00

35.00

37.00

39.00

42.00

45.00

EF (%)

64.00

65.00

68.00

71.00

75.00

76.00

80.00


Table 5: Percentile values of the echocardiographic measurements (n = 99)

DISCUSSION

The echocardiogram forms the cornerstone for pediatric cardiac evaluation, an important aspect of which is a quantification of cardiac structure in terms of dimensions. The dimensions of a child’s cardiac structure are affected by his or her hemodynamics and somatic growth11. Our study observed standard echocardiographic measures in healthy term newborns in Eastern India. There have been several other publications on this subject from across the globe but very little similar documentation from our part of the world. 

Eleven parameters such as right ventricular anterior wall thickness at end diastole (RVAWd), right ventricular end diastolic dimension (RVDD) at tricuspid annulus,  thickness of the interventricular septum at end diastole (IVSd), left ventricular dimension at end diastole (LVEDD),  left ventricular dimension at  end systole (LVESD), left ventricular posterior wall thickness at end diastole (LVPWd),  pulmonary and aortic diameter at the level of semilunar valve(PAD and AOD), left atrial diameter (LAD), fractional shortening (FS) and ejection fraction (EF) were recorded for each subject.

The measurements of cardiac structures and their comparison with nomograms are essential for preoperative planning for most congenital heart defects12.  A study comprising 2000 subjects in Europe where newborn babies had larger internal left ventricular diameter both during diastole and systole compared to that of the subjects of present study13. The IVS and LVPWd in our study were thinner compared to those of European newborn babies. Dimension of great vessels were smaller in our study than that of the European newborn babies. The mean right ventricular anterior wall thickness was found to be more in our subjects and the right ventricular internal diameter was also found to be more in the present study compared to those in European newborn. Mean left atrial diameter was found to be smaller in our newborn babies than that of European newborns. The mean values of cardiac dimensions in Indian newborns were found to be different from European newborn. These differences indicate that cardiac dimensions have racial differences and Western data cannot be extrapolated to fit the Indian pediatric cardiology nomograms.

Z‑Scores are essential to monitor the disease progression for the management of various acquired heart diseases such as Kawasaki disease or rheumatic heart disease14.  Major pediatric cardiac centers across the world have developed their own nomograms15. The Z scores of cardiac structures of the Indian pediatric population remains a challenge. An Indian study from Ajmer, Rajasthan and Mohali, Punjab included the population between 4 and 15 years of age16.  A study from Maharashtra published in 2018 included individuals aged 0 days to 16 years17. Our study is possibly the first publication from this subcontinent with exclusive focus on the first week of life. However, larger data bases and more representation from various social and economic backgrounds will provide more robust data in future.

LIMITATIONS

This study was conducted at Eastern India and failed to include subjects from different ethnic origins. However, this may paradoxically result in a strength of the study, because different racial compositions in a study group may present a bias when interpreting data. Moreover, the use of a homogeneous cohort makes it possible to derive normal values for a specific population and to compare these data with those from populations composed of different races and ethnicity.

CONCLUSIONS

This observational study concludes that Indian pediatric cardiac normative values are different from those established from Western experiences. Few parameters like RVAWd, IVSd, LVEDd and LVEDs have significant correlation with infant body weight. We further establish that all cardiac structural parameters of neonates do not corroborate with their body weight in a linear manner. Moreover, our literature search concludes that data on this subject is virtually non-existent from our part of the world. South East Asian populations differ from those of European descent and separate echocardiographic norms are needed from our part of the world.

REFERENCES

  1. Kaski JP, Daubeney PE. Normalization of echocardiographically derived paediatric cardiac dimensions to body surface area: time for a standardized approach. Eur J Echocardiogr 2009;10:44-5.
  2. Cantinotti M, Scalese M, Molinaro S, Murzi B, Passino C. Limitations of current echocardiographic nomograms for left ventricular, valvular and arterial dimensions in children: a critical review. J Am Soc Echocardiogr 2012;25:142-82.
  3. Colan SD. The why and how of Z scores. J AmSoc Echocardiogr 2013;26:38-40.
  4. Lopez L, Colan SD, Frommelt PC, Ending GJ, Kendall K, Younoszai AK, et al. Recommendations for quantification methods during the performance of a pediatric echocardiogram: a report from the Pediatric Measurements Writing Group of the American Society of Echocardiography Pediatric and Congenital Heart Disease Council. J Am Soc Echocardiogr 2010;23:465-95.
  5. Cantinotti M, Lopez L. Nomograms for blood flow and tissue Doppler velocities to evaluate diastolic function in children: a critical review. JAm Soc Echocardiogr 2013;26:126-41.
  6. Pettersen MD, Du W, Skeens ME, Humes RA. Regression equations for calculation of z-scores of cardiac structures in a large cohort of healthy infants, children, and adolescents: an echocardiographic study. J Am Soc Echocardiogr 2008;21:922-34.
  7. Sluysmans T, Colan SD. Theoretical and empirical derivation of cardiovascular allometric relationships in children. J Appl Physiol 2005;99:445-57.
  8. Cantinotti M, Scalese M, Murzi B, Assanta N, Spadoni I, Festa P, et al. Echocardiographic nomograms for ventricular, valvular and arterial dimensions in Caucasian children with a special focus on neonates, infants and toddlers. J Am Soc Echocardiogr 2014;27:179-91.
  9. Lytrivi ID, Bhatla P, Ko HH, Yau J, Geiger MK, Walsh R, et al. Normal values for left ventricular volume in infants and young children by the echocardiographic subxiphoid five-sixth area by length (bullet) method. J Am Soc Echocardiogr 2011;24:214-8.
  10.  Bhatla P, Nielsen JC, Ko HH, Doucette J, Lytrivi ID, Srivastava S. Normal values of left atrial volume in pediatric age group using a validated allometric model. Circ Cardiovasc Imaging 2012;5:791-6.
  11.  Gutgesell HP, Rembold CM. Growth of the human heart relative to body surface area. Am J Cardiol 1990;65:6628.
  12.  Awori MN, Leong W, Artrip JH, O’Donnell C. Tetralogy of fallot repair: Optimal z-score use for transannular patch insertion. Eur J Cardiothorac Surg 2013;43:4836.
  13.  Normal values of M mode echocardiographic measurements of more than 2000 healthy infants and children in central Europe. C Kampmann, C M Wiethoff, A Wenzel, G Stolz, M Betancor, C-F Wippermann, R-G Huth, P Habermehl,M Knuf, T Emschermann, H Stopfkuchen. Heart 2000;83:667–672.
  14.  Chubb H, Simpson JM. The use of ZScores in paediatric cardiology. Ann Pediatr Cardiol 2012;5:17984.
  15.  Roberson DA, Cui W, Chen Z, Madronero LF, Cuneo BF. Annular and septal Doppler tissue imaging in children: Normal zscore tables and effects of age, heart rate, and body surface area. J Am Soc Echocardiogr 2007;20:127684.
  16.  Gokhroo RK, Anantharaj A, Bisht D, Kishor K, Plakkal N, Aghoram R, et al. A pediatric echocardiographic Zscore nomogram for a developing country: Indian pediatric echocardiography study – The Zscore. Ann Pediatr Cardiol 2017;10:318.
  17.  Trivedi B, Chokhandre M, Dhobe P, Garekar S. Estimation of Z-scores of cardiac structures in healthy Indian pediatric population. J Indian Acad Echocardiogr Cardiovasc Imaging 2018;2:147-54.
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