Which arrhythmia is most commonly found in adolescent patients with an underlying congenital heart defect?

Supraventricular tachycardia (SVT) is indeed the arrhythmia most commonly observed in adolescent patients with underlying congenital heart defects. SVT is characterized by an abnormally fast heart rate that originates above the ventricles; it is particularly prevalent in individuals who have had surgical interventions or other cardiac modifications due to congenital heart defects.

These defects can disrupt the normal conduction pathways in the heart, making patients more susceptible to situations that trigger SVT. This type of tachycardia can result from reentrant circuits or automatic foci, often exacerbated by stress or change in body position, which can be common in adolescents.

Understanding the implications of congenital heart defects on electrical conduction and rhythm is crucial in managing patients who may exhibit these arrhythmias. While ventricular fibrillation, bradycardia, and premature ventricular contractions can occur in this population, they are less frequently seen than SVT due to the specific pathways of rhythm issues and the types of cardiac malformations commonly encountered in adolescents.