Background: Atrial flutter not responding to medications could be secondary to structural malformations of heart.
Case characteristics: A 5-year-old child with resistant arrhythmia, with onset in neonatal period.
Observations: Multiple right atrial diverticuli were detected on CT angiography and cardiac catheterization. Patient reverted to sinus rhythm following surgical excision of diverticuli.
Message: In cases of intractable supraventricular tachycardia, structural anomalies of atrium should be suspected.