Amiodarone is safe and highly effective therapy for supraventricular tachycardia in infants

Background The clinical effectiveness of amiodarone must be weighed against the likelihood of adverse effects. Adverse effects are less common in chil dren than in adults, yet there have been no large studies assessing the eff icacy and safety of amiodarone in the first 9 months of life. We sought to assess the safety and efficacy of amiodarone as primary therapy for suprave ntricular tachycardia in infancy. Methods We evaluated the clinical course of 50 consecutive infants and neon ates (1.0 +/- 1.5 months, 35 male) treated with amiodarone for supraventric ular tachyarrhythmias between July 1994 and July 1999. At presentation, con genital heart disease, congestive heart failure, or ventricular dysfunction were present in 24%, 36%, and 44% of the infants, respectively. infants re ceived a 7- to 10-day load of amiodarone at either 10 or 20 mg/kg/d. If thi s failed to control the arrhythmia, oral propranolol (2 mg/kg/d) was added. Patients were followed up for 16.0 +/- 13.0 months, and antiarrhythmic dru gs were discontinued as tolerated. Results Rhythm control was achieved in all patients. Of the 34 patients who have reached 1 year of age, 23 (68%) have remained free of arrhythmia, des pite discontinuation of propranolol and amiodarone. Growth and development remained normal for age. Higher loading doses of amiodarone were associated with an increase in the corrected QT interval, but no proarrhythmia was se en. There were no side effects necessitating drug withdrawal. Conclusions Amiodarone is an effective and safe therapy for tachycardia con trol in infancy.