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 children than in adults, yet there have been no large studies assessing the efficacy 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 supraventricular tachycardia in infancy.


METHODS
We evaluated the clinical course of 50 consecutive infants and neonates (1.0+/-1.5 months, 35 male) treated with amiodarone for supraventricular tachyarrhythmias between July 1994 and July 1999. At presentation, congenital heart disease, congestive heart failure, or ventricular dysfunction were present in 24%, 36%, and 44% of the infants, respectively. Infants received a 7- to 10-day load of amiodarone at either 10 or 20 mg/kg/d. If this 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 drugs 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, despite 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 seen. There were no side effects necessitating drug withdrawal.


CONCLUSIONS
Amiodarone is an effective and safe therapy for tachycardia control in infancy.
Etheridge
S P
SP
Division of Pediatric Cardiology, Department of Pediatrics, University of Utah Health Sciences Center and Primary Children's Medical Center, Salt Lake City, Utah 84113, USA. pcsether@ihc.com
Craig
J E
JE
Compton
S J
SJ
D000638:Amiodarone / Q000627:therapeutic use*; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D013617:Tachycardia, Supraventricular / Q000188:drug therapy*
D000889:Anti-Arrhythmia Agents; D000638:Amiodarone