Which arrhythmia is most commonly observed in children with Wolff-Parkinson-White syndrome?

In children with Wolff-Parkinson-White (WPW) syndrome, the most commonly observed arrhythmia is supraventricular tachycardia (SVT). WPW is characterized by the presence of an accessory conduction pathway that allows for premature ventricular activation, leading to a rapid heart rate. The accessory pathway can facilitate reentrant circuits, which are responsible for the episodes of SVT.

SVT in the context of WPW frequently presents as a sudden onset of palpitations or an increased heart rate, which can often be alarming for both the child and caregivers. Diagnosis is typically confirmed through an electrocardiogram (ECG) that demonstrates delta waves and a short PR interval associated with the accessory pathway.

Other arrhythmias listed are less common in WPW. For instance, ventricular fibrillation is a life-threatening condition that is not typical in young patients with WPW unless there are significant underlying heart diseases or structural abnormalities. Bradycardia, which refers to a slow heart rate, would not be associated with WPW as the syndrome typically leads to tachyarrhythmias. Premature ventricular contractions, while they can occur in many individuals, are not specific to WPW and are not commonly the primary arrhythmia