Prevalence of Wolff-Parkinson-White syndrome, association with congenital heart disease, and natural history in newborns
Authors: Paerregaard M , Haartmann J , Pihl C , Pietersen A , Iversen K K , Bundgaard H , Christensen A H 
Published: October 2022

Abstract

Background
Wolff-Parkinson-White (WPW) syndrome is characterized by an accessory electrical pathway between the atria and ventricles. Clinically, the condition can lead to supraventricular tachycardia, and is associated with sudden cardiac death and congenital heart disease. Studies investigating the prevalence, associated structural cardiac abnormalities, and natural history in newborns are few.

Purpose
To determine the prevalence of WPW syndrome in newborns, describe electrocardiographic and echocardiographic characteristics, and the natural history in childhood.

Methods
Electrocardiograms (ECGs) and echocardiograms of newborns (aged 0–30 days) from a large, prospective, general population study were included. WPW cases were identified through manual evaluation of outliers in PR-interval, QRS-duration, and QRS axis. Newborns with suspected or confirmed pre-excitation on their initial ECG were offered a cardiac follow-up. Localization of the accessory pathway was assessed utilizing a QRS polarity algorithm. Cases were matched 1:4 to controls by age, sex, weight and gestational age.

Results
Among the 17,489 ECGs we identified 17 (76% boys) newborns with definite WPW syndrome consistent with a prevalence of 0.1%. At follow-up (available in 12/17 children) at a mean age of three years, the WPW pattern remained in three children while the ECG had normalized in the nine remaining children. The median values for the newborns' heart rate, PR-interval, QRS-duration, QTc(Bazett), the maximum amplitude in R-V1 and S-V6 in cases and controls were 131 vs. 142 beats per minute, 80 vs. 96 ms, 74 vs. 56 ms, 449 vs. 420 ms, 1,562 vs. 1,028 μV and 546 vs. 693 μV, respectively (all p&lt;0.05, Figure 1). The newborns' QRS axis, max amplitude in S-V1 and R-V6 did not differ among cases and controls (all p&gt;0.05). Echocardiographic measurements of the newborns' left ventricular diameter and function, wall thicknesses, and doppler measurements of trans-mitral- and main pulmonary artery blood flow did not differ significantly between cases and controls (all p&gt;0.05). The accessory electrical pathway was left-sided in 14 (82%) of the newborns. One newborn had significant mitral regurgitation while all other newborns had structurally normal hearts; there were no cases of Ebstein's anomaly.

Conclusion
The prevalence of WPW syndrome in our cohort of asymptomatic newborns was 0.1%. The syndrome was more frequent in boys, the accessory pathway was mostly left-sided, and was associated with changes in several ECG parameters, but generally not associated with structural heart disease. A striking observation was, that the WPW pattern in the majority of children could not be reproduced on follow-up ECGs at a mean age of three years, suggesting either that the ECG pattern is intermittent, or normalization occurs.

Funding Acknowledgement
Type of funding sources: Foundation. Main funding source(s): The Danish Heart Foundation