Amiodarone therapy for drug-refractory fetal tachycardia.
BACKGROUND
Fetal tachycardia complicated by ventricular dysfunction and hydrops fetalis carries a significant risk of morbidity and mortality. Transplacental digoxin is effective therapy in a small percentage, but there is no consensus with regard to antiarrhythmic treatment if digoxin fails. This study evaluates the safety, efficacy, and outcome of amiodarone therapy for digoxin-refractory fetal tachycardia with heart failure.


RESULTS
Fetuses with incessant tachycardia and either hydrops fetalis (n=24) or ventricular dysfunction (n=2) for whom digoxin monotherapy and secondary antiarrhythmic agents (n=13) were not effective were treated transplacentally with a loading dose of oral amiodarone for 2 to 7 days, followed by daily maintenance therapy for <1 to 15 weeks. Digoxin therapy was continued throughout gestation. Newborns were studied by transesophageal pacing or ECG monitoring to determine the mechanism of tachycardia. Three fetuses were delivered urgently in tachycardia during amiodarone loading, and 3 required additional antiarrhythmic agents for sustained cardioversion. Amiodarone or amiodarone combinations converted 14 of 15 (93%) with reentrant supraventricular tachycardia, 2 of 2 with ventricular or junctional ectopic tachycardia, and 3 of 9 (33%) with atrial flutter. Amiodarone-related adverse effects were transient in 5 infants and 8 mothers. Mean gestational age at delivery was 37 weeks, with 100% survival.


CONCLUSIONS
Orally administered amiodarone is safe and effective treatment for drug-refractory fetal tachycardia, specifically reentrant supraventricular tachycardia, junctional ectopic, or ventricular tachycardia, even when accompanied by hydrops fetalis or ventricular dysfunction.
Strasburger
Janette F
JF
Children's Hospital of Wisconsin, Division of Cardiology, MS-713, 9000 W Wisconsin Ave, Milwaukee, WI 53201, USA. jstrasbu@mcw.edu
Cuneo
Bettina F
BF
Michon
Maaike M
MM
Gotteiner
Nina L
NL
Deal
Barbara J
BJ
McGregor
Scott N
SN
Oudijk
Martijn A
MA
Meijboom
Erik J
EJ
Feinkind
Leonard
L
Hussey
Michael
M
Parilla
Barbara V
BV
D000638:Amiodarone / Q000009:adverse effects / Q000627:therapeutic use*; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001282:Atrial Flutter / Q000188:drug therapy; D004077:Digoxin / Q000627:therapeutic use; D004562:Electrocardiography; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis / Q000188:drug therapy*; D006801:Humans; D015160:Hydrops Fetalis / Q000150:complications; D008297:Male; D011247:Pregnancy; D013610:Tachycardia / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D017211:Treatment Failure; D016896:Treatment Outcome; D018754:Ventricular Dysfunction / Q000150:complications
D000889:Anti-Arrhythmia Agents; D004077:Digoxin; D000638:Amiodarone