Left Axis Deviation in Children Without Previously Known Heart Disease

The Evolution of the Neonatal QRS Axis during the First Four Weeks of Life

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.

The Significance of Left Axis Deviation in the Pediatric Population: A Meta-Analysis

Left axis deviation (LAD) in children is rare but may be associated with structural heart disease. The aim of this study is to systematically assess the significance of LAD in the pediatric population. We included studies listed in PubMed, EMBASE, Web of Science, Cochrane databases, and Google Scholar before May 31, 2018 and their reference lists. Nine selected studies were grouped into two categories: (1) prevalence of heart diseases in children with LAD on ECG and (2) prevalence of LAD in children with healthy hearts. Two authors independently extracted data using a standardized data extraction form. We identified nine studies including 7514 subjects. Among children with LAD, 66.3% (95% CI 36.9-86.9%) had heart disease. There was heterogeneity amongst studies with Q-value of 142.5 and I² of 97.2%. The mean LAD rate was 1.6% in children with healthy hearts with 95% CI (0.4-2.2%) with Q-value of 11.8, I² 66.3% and T 0.34 with p value of 0.018. The limitation of study is that the included studies spanned 7 decades from the 1950s to 2018. Primary diagnostic modalities have evolved over time and the definition of LAD also varied among studies. In conclusion, LAD is associated with children with heart diseases, but may also be observed in healthy children. The degree of LAD axis correlated with the likelihood of congenital heart disease (CHD). Physical examination is crucial for identifying CHD in individuals with LAD.