Electrocardiographic Evaluation of Normal Newborns in the First Week of Life – Observational Study

Abstract Background The neonatal period is marked by major changes in the cardiovascular system, especially in the first week of life. Unlike the adult population, studies on electrocardiogram (ECG) data in the neonatal period are scarce. This is the first study to describe electrocardiographic changes in a cohort of newborns with normal echocardiograms. Objectives To analyze the electrocardiographic patterns of a population of full-term NB, without any cardiac morphological or functional anomalies, and compare the results with the literature. Methods In this observational study, echocardiograms and ECG results from 94 newborns divided in three age groups (up to 24 hours, between 25 and 72 hours, and between 73 and 168 hours of life) were evaluated and compared with those reported by Davignon et al. A p-value <0.05 was considered statistically significant. Results There were significant differences in T-wave direction in leads V1 (p= 0.04), V2 (p= 0.02), V3 (p= 0.008) and V4 (p= 0.005) between the three age groups. There were differences between our findings and the current literature in most of the parameters. Conclusion Term newborns within 24 hours of life showed significantly more positive T waves than older ones. Many differences from the Davignon’s ECG parameters were found, particularly in the P, Q, R, S amplitudes, QRS duration, R/S and R+S. These findings indicate that more studies are needed for a definitive interpretation of the ECG in newborns.

研究背景：新生儿期以心血管系统的显著变化为特征，尤其在出生后第一周。与成人人群不同，针对新生儿期心电图（Electrocardiogram, ECG）数据的研究较为匮乏。本研究首次描述了超声心动图（echocardiogram）结果正常的新生儿队列的心电图变化特征。
研究目的：分析无任何心脏形态或功能异常的足月新生儿队列的心电图模式，并将研究结果与现有文献进行对比。
研究方法：本项观察性研究对94名新生儿的超声心动图及心电图结果进行分析，按出生后年龄将其分为3个组别：出生后24小时内、25~72小时、73~168小时，并将研究结果与Davignon等人的报道进行对比。本研究将P值（P-value）<0.05认定为具有统计学显著性。
研究结果：3个年龄组在V1、V2、V3、V4导联的T波方向上存在显著差异（分别对应P=0.04、0.02、0.008、0.005）。本研究的多数参数结果与现有文献存在差异。
研究结论：出生后24小时内的足月新生儿，其T波正向的比例显著高于年龄更大的新生儿。本研究发现多项与Davignon等人报道的心电图参数存在差异，尤其体现在P波、Q波、R波、S波的振幅，QRS波时限，R/S比值以及R+S振幅上。上述结果表明，亟需开展更多研究以明确新生儿心电图的标准化解读方案。