Treatment of atrial ectopic tachycardia in infants < 6 months old.

Nineteen infants < 6 months old who had atrial ectopic tachycardia (AET) were treated with antiarrhythmic drugs. AET was controlled with digoxin in 1 patient, propafenone in 2, digoxin with propafenone in 9, digoxin with amiodarone in 4, and digoxin with propafenone and amiodarone in 2; radiofrequency ablation was performed in 1 drug-resistant case. AET resolved in 14 of 15 infants within 1 year. Drug side effects occurred in 5 patients. We conclude that AET in infants < 6 months old can be successfully treated with antiarrhythmic drugs, and we recommend a three-step approach with digoxin, a class 1C antiarrhythmic drug, and a class 3 drug. Resolution of AET in infants is frequent.