Atrial fibrillation without cardiac anomaly in a 9-year-old child

Atrial fibrillation (AF), the most common chronic arrhythmia in adults, is rarely reported in children. Moreover, most of the previously reported children with AF have comorbidities, such as structural heart diseases, rheumatic diseases, and thyroid diseases. This case report is about a healthy 9-year-old boy who was diagnosed with AF without cardiac anomaly. He visited the emergency department with chest pain and palpitation, lasting 2 hours. His electrocardiogram showed narrow-complex tachycardia, which led to the diagnosis of supraventricular tachycardia. The administration of adenosine revealed rapid irregular P waves. After electrical cardioversion, cardiac rhythm was converted to normal sinus rhythm. This case report suggests that when children with narrow-complex tachycardia visit the emergency department, the possibility of AF, in addition to supraventricular tachycardia, should be considered if the RR intervals are markedly irregular.