The median QRS axis in healthy newborns shifted leftward from 119° at 0-7 days to 102° at 22-28 days (p<0.001), and was affected by sex and gestational age.
Cohort (n=12,317)
What is the normal evolution of the QRS axis in healthy newborns during the first 4 weeks of life?
The neonatal QRS axis undergoes a gradual leftward shift during the first 4 weeks of life, influenced by sex and gestational age, providing updated reference values for clinical use.
p-value: p=<0.001
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 0.05). 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.
Pærregaard et al. (Fri,) conducted a cohort in Healthy newborns (n=12,317). The median QRS axis in healthy newborns shifted leftward from 119° at 0-7 days to 102° at 22-28 days (p<0.001), and was affected by sex and gestational age.