The electrocardiogram in normal newborn infants: correlation with hemodynamic observations

QTc Interval Reference Values and Their (Non)-Maturational Factors in Neonates and Infants: A Systematic Review

QTc interval measurement is a widely used screening tool to assess the risk of cardiac diseases, arrhythmias, and is a useful biomarker for pharmacovigilance. However, the interpretation of QTc is difficult in neonates due to hemodynamic maturational changes and uncertainties on reference values. To describe trends in QTc values throughout infancy (1 year of life), and to explore the impact of (non)-maturational changes and medicines exposure, a structured systematic review (PROSPERO CRD42022302296) was performed. In term neonates, a decrease was observed over the first week of life, whereafter values increased until two months of age, followed by a progressive decrease until six months. A similar pattern with longer QTc values was observed in preterms. QTc is influenced by cord clamping, hemodynamic changes, therapeutic hypothermia, illnesses and sleep, not by sex. Cisapride, domperidone and doxapram result in QTc prolongation in neonates. Further research in this age category is needed to improve primary screening practices and QTcthresholds, earlier detection of risk factors and precision pharmacovigilance.

Normal ECG standards and percentile charts for infants, children and adolescents

BACKGROUND

Normal ECG standards in newborns, infants, children and adolescents have been collected and published by many authors. Only those by Davignon et al., Rijinbeek et al. and our two studies covered all ages from birth to adolescence. The standards reflecting the growth and development of the heart in infants, children and adolescents remained to be studied and explored.

METHODS

We selected from our ECG database, after discussions and consultation, 15 key ECG parameters and analyzed for their age- and sex-specific mean, standard deviation and 2nd to 98th percentiles and their percentile charts were constructed.

RESULTS

The ranges and distributions of the normal ECG standards, means and 2nd to 98th percentiles of 15 key parameters were established.

CONCLUSION

A complete set of normal ECG standards of 15 key parameters from birth to adolescents is available for clinicians and researchers.

Comparative study of the electrocardiograms of healthy fullterm and premature newborns

The electrocardiograms of 421 healthy fullterm and premature newborns, recorded on the fifth day of life, were evaluated for possible systematic differences related to gestational age. All newborns were appropriate for gestational age and were divided into four groups according to birthweight. As birthweight increased, we noted: (a) a progressive rightward shifting of the QRS axis in the frontal plane; (b) an increase in the amplitude mainly of the precordial R and S waves reflecting the right ventricle and both ventricles combined, whereas a less significant increase or even a decrease was noted in the R and S waves reflecting the left ventricle; (c) a more frequent occurrence of diphasic and positive T waves in the right precordial leads; and (d) a prolongation in the duration of the P wave and the QRS complex. These findings reflect both an increase in total myocardial mass as well as a progressive right ventricular predominance, as birthweight or gestational age increases. Practical implications for electrocardiographic identification of cardiac hypertrophy in newborns of different gestational age are discussed.

Computer analysis of changes in frank vectorcardiograms of 666 normal infants in the first 72 hours of life

Frank vectorcardiograms (VCGs) were collected on magnetic tape for 666 normal newborn infants at 1, 6, 12, 24, 36, 48, 60, and 72 hours after birth and analyzed by computers. The final total included 1,337 VCGs for white babies and 413 for blacks. No previous report has been made for the normal neonate with such a large sample, and no previous substantiation exists of possible age or sex differences at this early age. This study establishes a statistically significant change in vectorcardiographic patterns over the first three days, specifically in the measurements P duration, QRS duration, maximal spatial QRS amplitude, S in lead x, and T in lead z, as well as for several time-normalized QRS vectors. (P less than or equal to .005.) Racial differences were significant for T waves in lead z. This study supports the use of vectorcardiographic standards sensitive to the age of the newborn as well as to race.

Early clamping versus stripping of card: comparative study of electrocardiogram in neonatal period

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