Abstract
Background: 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. Methods: 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. Results: 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°. Conclusions: 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.
Original language | English |
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Journal | Neonatology |
Volume | 118 |
Issue number | 2 |
Pages (from-to) | 155-162 |
Number of pages | 8 |
ISSN | 1661-7800 |
DOIs | |
Publication status | Published - Jun 2021 |
Bibliographical note
Funding Information:This work was supported by the Danish Heart Foundation (Grant 20-R140-A9569–22168, MMP), the Danish Children Heart Foundation (Grant 19-R112-A5248–26048, MMP), Snedker-mester Sophus Jacobsen and wife Astrid Jacobsen’s foundation, The Research Council at Herlev-Gentofte Hospital, The Health Foundation Denmark, The Independent Research Fund Denmark (Grant 0134–00363B, AHC), and Toyota-Fonden, Denmark.
Funding Information:
This work was supported by the Danish Heart Foundation (Grant 20-R140-A9569?22168, MMP), the Danish Children Heart Foundation (Grant 19-R112-A5248?26048, MMP), Snedkermester Sophus Jacobsen and wife Astrid Jacobsen?s foundation, The Research Council at Herlev-Gentofte Hospital, The Health Foundation Denmark, The Independent Research Fund Denmark (Grant 0134?00363B, AHC), and Toyota-Fonden, Denmark.
Publisher Copyright:
© 2021 S. Karger AG. All rights reserved.
Keywords
- Electrocardiography
- Newborns
- QRS axis
- Reference values