Neonatal Atrial Flutter: Adenosine Dilemma

Background: Atrial flutter (AFl) is a rare type of neonatal tachyarrhythmia, which is recognized by saw-tooth waves on electrocardiogram (ECG), and an atrial rate of up to 500 beats/minute. The mechanism of AFl is sustained by a macro-reentrant circuit pathway which is limited to the atrial wall, however the atrioventricular (AV) node is not involved of the reentrant circuit. Case Presentation: A 2-day-old, full term, male infant was born to a hypertensive mother, by cesarean section, presented to the pediatric emergency department at Maternity and Children hospital with history of cyanosis and decrease oral intake. At the physical examination, both tachypnea (70/min) and tachycardia (218/bpm) were determined. An electrocardiogram confirmed atrial flutter with 3:1 atrioventricular conduction. AFl didn't respond to adenosine administration, therefore, electrical cardioversion was required. After conversion to normal sinus rhythm, amiodarone and propranolol therapy were started to maintain sinus rhythm afterward. With no further incidence of AFl or other arrhythmias, the infant was discharged at 9 th day of life and in good general state with propranolol therapy, and was followed in the cardiac clinic. Conclusion: Electrical cardioversion with energy of (0.5-1 J/Kg) proved to be the most effective in establishing sinus rhythm, and is safe for neonatal patients. Adenosine doesn't treat tachycardia of atrial origin, such as AFl. However, adenosine administration may help in identifying AFl, demonstrating the arrhythmia-characteristic saw-tooth waves in the ECG.