Prenatal diagnosis of sustained bradycardia with 1 : 1 atrioventricular conduction.
OBJECTIVE
The aims of this study were to elucidate the clinical course of fetal bradycardia with 1 : 1 atrioventricular conduction, and to discuss the optimal management of affected fetuses in the second and third trimesters of pregnancy.


METHODS
The hospital records of five fetuses with the diagnosis of bradycardia (100 bpm) with 1 : 1 atrioventricular conduction between 1981 and 2000 in our institution were reviewed. Atrioventricular conduction was evaluated by simultaneous M-mode echocardiographic tracing of the atria and the ventricles.


RESULTS
The gestational ages at referral ranged from 19 to 36 (median, 25) weeks, and fetal heart rates ranged from 60 to 80 (median, 80) bpm. Postnatal electrocardiography revealed sinus bradycardia in four (two of which were siblings) of the five cases, and junctional rhythm in the remaining case. Two fetuses with congenital heart defects (CHDs) were delivered by Cesarean section but died postnatally. The three fetuses without CHDs were delivered vaginally and have survived to date for 6, 8 and 15 years.


CONCLUSIONS
Fetal bradycardia with 1 : 1 atrioventricular conduction caused by sustained sinus bradycardia or wandering pacemaker is an important type of fetal arrhythmia. Further investigations with a larger number of cases are required to determine the risk factors for predicting the outcome of affected fetuses.
Maeno
Y
Y
Department of Pediatrics Child Health, Kurume University, Kurume, Japan.
Rikitake
N
N
Toyoda
O
O
Kiyomatsu
Y
Y
Miyake
T
T
Himeno
W
W
Hirose
A
A
Hori
D
D
Kamura
T
T
Kato
H
H
D001919:Bradycardia / Q000000981:diagnostic imaging*; D004452:Echocardiography / Q000379:methods; D004562:Electrocardiography / Q000379:methods; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging*; D005865:Gestational Age; D006801:Humans; D011181:Postnatal Care; D011247:Pregnancy; D011256:Pregnancy Outcome; D016216:Ultrasonography, Prenatal / Q000379:methods*