Department of Cardiology, Herlev-Gentofte Hospital, Copenhagen University Hospital, Copenhagen, Denmark.
Department of Cardiology, The Capital Regions Unit for Inherited Cardiac Diseases, The Heart Center, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
Neonatology. 2021;118(2):155-162. doi: 10.1159/000513526. Epub 2021 Mar 10.
The QRS axis represents the sum and orientation of the ventricular depolarization. Accurate interpretation of abnormalities in the QRS axis may facilitate early diagnosis of heart disease in newborns. We aimed at describing the evolution of the QRS axis during the first 4 weeks of life and provide reference values from healthy newborns.
The Copenhagen Baby Heart Study is a prospective general population study that offered cardiac evaluation during the first month of life to all newborns delivered in the Copenhagen area.
Electrocardiograms from 12,317 newborns (52% boys; mean age 12 days) with normal echocardiograms were included. The median QRS axis was 119° at the ages 0-7 days and shifted leftward to 102° at the ages 22-28 days (p < 0.001). We found that girls had a significantly less pronounced right-shifted axis than boys (p < 0.001) and that increasing gestational age (GA) was associated with a more pronounced right-shifted axis (p < 0.05). Infant size did not affect the axis (p > 0.05). Only 0.5% had an axis within the interval 0 to -90° and 1.1% in the interval +240 to +30°.
The QRS axis showed a gradual leftward-shift during the first 4 weeks of life and was affected by sex and GA but unaffected by infant size. Less than 1% of the newborns had a QRS axis between 0 and -90°. This study represents updated reference values, which may facilitate the clinical handling of newborns.
QRS 轴代表心室除极的总和和方向。准确解读 QRS 轴的异常有助于早期诊断新生儿心脏病。我们旨在描述新生儿生命的前 4 周内 QRS 轴的演变，并为健康新生儿提供参考值。
哥本哈根婴儿心脏研究是一项前瞻性的一般人群研究，为哥本哈根地区出生的所有新生儿在生命的第一个月提供心脏评估。
共纳入 12317 名心电图正常的新生儿（男婴占 52%；平均年龄 12 天）。0-7 天的中位数 QRS 轴为 119°，22-28 天左移至 102°（p<0.001）。我们发现女孩的右移轴比男孩明显小（p<0.001），且胎龄（GA）增加与右移轴明显相关（p<0.05）。婴儿大小对轴无影响（p>0.05）。仅 0.5%的新生儿的轴在 0 到-90°之间，1.1%的新生儿的轴在 240 到 30°之间。
QRS 轴在生命的前 4 周内逐渐左移，受性别和 GA 的影响，但不受婴儿大小的影响。小于 1%的新生儿的 QRS 轴在 0 到-90°之间。本研究提供了更新的参考值，有助于新生儿的临床处理。
