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Fetal sinus bradycardia and the long QT syndrome
E Beinder1, T Grancay, T Menéndez
1Department of Obstetrics and Gynecology, University Hospital of Erlangen/Nuremberg, Germany. ernst.beinder@gyn.med.uni-erlangen.de
Insights
Fetal sinus bradycardia detected via cardiotocogram may indicate long QT syndrome (LQTS). Early detection through postnatal electrocardiography is crucial for affected newborns to confirm or rule out this serious heart condition.
Area of Science:
- Cardiology
- Fetal Medicine
- Genetics
Background:
- Long QT syndrome (LQTS) is linked to sudden infant death syndrome.
- Newborns with prolonged Q-T intervals often exhibit sinus bradycardia.
Purpose of the Study:
- To investigate the correlation between fetal sinus bradycardia and Long QT Syndrome.
- To determine if cardiotocograms can predict LQTS in fetuses.
Main Methods:
- Identified 18 children diagnosed with Long QT Syndrome.
- Analyzed cardiotocograms from 17 fetuses during pregnancy and delivery.
Main Results:
- Persistent fetal sinus bradycardia (heart rate <120 bpm) was observed in 71% (12/17) of fetuses with LQTS.
- Two fetuses also showed intermittent tachyarrhythmias.
Conclusions:
- Cardiotocogram findings of sinus bradycardia during pregnancy may suggest fetal LQTS.
- Postnatal electrocardiography is recommended for infants with suspected fetal bradycardia to diagnose LQTS.
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.
Study Design:
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.
Conclusion:
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.