Fetal sinus bradycardia and the long QT syndrome.
OBJECTIVE
Recent evidence in literature shows that the long QT syndrome accounts for a fraction of the sudden infant death syndrome. Newborn infants with prolongation of the Q-T interval often show sinus bradycardia, which led us to test whether children who were diagnosed with long QT syndrome also show sinus bradycardia in the cardiotocogram before birth.


METHODS
We identified 18 children who were born from singleton pregnancies at or near term in whom long QT syndrome (corrected QT interval, >0.440 second) was diagnosed after birth or in childhood. Cardiograms during pregnancy and delivery were available from 17 of the 18 children.


RESULTS
The cardiotocogram showed persistent fetal sinus bradycardia (baseline heart rate permanently below 120 beats/min) in 12 of 17 fetuses (71%) with long QT syndrome. Two fetuses had additional intermittent tachyarrhythmias.


CONCLUSIONS
Sinus bradycardia in the cardiotocogram during delivery or in pregnancy may indicate long QT syndrome in the fetus. Postnatal electrocardiography should be performed in these children to rule out or confirm a prolongation of the Q-T interval.
Beinder
E
E
Department of Obstetrics and Gynecology, University Hospital of Erlangen/Nuremberg, Germany. ernst.beinder@gyn.med.uni-erlangen.de
Grancay
T
T
Menéndez
T
T
Singer
H
H
Hofbeck
M
M
D001146:Arrhythmia, Sinus / Q000150:complications* / Q000175:diagnosis / Q000196:embryology*; D001919:Bradycardia / Q000150:complications* / Q000175:diagnosis / Q000196:embryology*; D015148:Cardiotocography; D004562:Electrocardiography; D005318:Fetal Heart / Q000503:physiopathology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008133:Long QT Syndrome / Q000150:complications*; D013610:Tachycardia / Q000150:complications / Q000175:diagnosis / Q000196:embryology