We report the case of a 59-year-old patient, with a history of severe chest trauma with rib fractures at the age of 20 and recent onset of fatigue and palpitations, who was diagnosed with atrial tachycardia, which was converted pharmacologically. Cor triatriatum or Ebstein's anomaly were suspected on initial imaging studies (transthoracic echocardiography and MRI). Due to recurrence of arrhythmia, he subsequently underwent repeat echocardiographic evaluation, which established a diagnosis of right atrial aneurysm. The arrhythmia was converted electrically. The patient has remained asymptomatic during 18 months of follow-up, without arrhythmia recurrence, medicated with carvedilol (after an initial period with amiodarone) and warfarin.