Background: Concern exists in literature about the clinical course, the best acute and chronic treatment and the prognosis of idiopathic neonatal atrial flutter. The aim of our study was to evaluate this in a population of our patients with this type of arrhythmia.
Methods: Six infants (3 M, 3 F, mean age 42 +/- 62 days, range 1-150) affected with atrial flutter without structural heart disease were studied and then acutely and chronically treated. The effectiveness of chronic antiarrhythmic treatment was evaluated with Holter monitoring every 3 months for the first year of life and with transesophageal atrial pacing.
Results: Mean arrhythmia cycle length was 180 +/- 34 ms with atrioventricular conduction ratio ranging between 1:1 and 3:1. Two patients with clinical signs of heart failure were successfully treated with DC shock. Transesophageal overdrive atrial pacing was successfully used in one patient treated with i.v. propafenone without benefit. In the remaining three patients, cardioversion was achieved with amiodarone after digoxin had failed in all three and propafenone had failed in two of them. To prevent recurrences, we treated four patients with amiodarone, one with amiodarone combined with propranolol and one with digoxin. During the follow-up (22 +/- 11 months), neither arrhythmia recurrences nor side-effects of the therapy occurred.
Conclusions: Neonatal atrial flutter is an arrhythmia with significant acute morbidity but an excellent long-term prognosis. Electrical cardioversion is the first-choice treatment when the arrhythmia is not well-tolerated hemodynamically, while class III antiarrhythmic drugs such as amiodarone should be preferred in the other cases.