- What Are Fetal Arrhythmias?
It is not usual for your baby to have an irregular heartbeat at some point during pregnancy. More often than not, a fetal arrhythmia is a benign condition. Nonetheless, it is a condition the physicians at Fetal Care Center Dallas will pay close attention to once detected.
Fetal heart rhythm abnormalities are generally categorized by heart rate and the regularity with which the arrhythmia occurs. Almost all arrhythmias fall into one of three categories: irregular, tachycardic or bradycardic. Physicians at Fetal Care Center Dallas are trained to diagnose and treat the full range of fetal arrhythmias.
- Premature atrial contractions/Premature ventricular contractions: Characterized by a heartbeat that originates in a different part of the atrium than it normally would. This condition typically causes no serious health problems.
- Tachycardia: Characterized by a heartbeat that is too fast, greater than 180 beats per minute.
- Supraventricular tachycardia (SVT)
- Atrial flutter
- Atrial fibrillation
- Chaotic Atrial Tachycardia
- Premature Junctional Reciprocating Tachycardia (PJRT)
- Sinus Tachycardia
- Ventricular tachycardia
- Bradycardia: Characterized by a heartbeat that is too slow, below 100 beats per minute.
- Blocked atrial bigeminy
- Complete Heart Block
- Incomplete Heart Block (first and second degree)
- Long QT syndrome: Rare heart rhythm condition characterized by fast, chaotic heartbeats.
* Normal fetal heart rates range from 120 to 160 bpm at 30 gestational weeks, and from 110 to 160 bpm at term.
- Prenatal Diagnosis of Fetal Arrhythmias
A fetal arrhythmia may be detected during a routine maternal prenatal exam once fetal tones are available, at around the tenth week. You are not likely to experience any symptoms and will not notice any decreased fetal activity.
Non-invasive ultrasound technology may be used to diagnose the specific arrhythmia, evaluate your baby’s heart structure and function, and look for signs of hydrops (excess fluid). If a fetal tachycardia or bradycardia is heard, a fetal echocardiogram and umbilical Doppler studies may also be performed to further evaluate your baby’s blood flow pattern, heart structure and heart rate.
Temporary slowing of the fetal heart rate with immediate return to a normal rate is common during pregnancy when you are in certain positions and does not require further cardiac evaluation. The skilled physicians at Fetal Care Center Dallas are trained to differentiate between an isolated incident of slowing of the heart and persistent bradycardia, which requires immediate evaluation and potential intervention. Based on the diagnosis, we will discuss all possible treatment options with you and guide you through.
- How We Treat Fetal Arrhythmias
How we medically manage fetal heart rhythm abnormalities depends on the condition and its extent. An irregular heartbeat may have no effect on a fetus and require little intervention. Fetal tachycardia or bradycardia can cause heart failure either in the womb or at birth. Bradycardia related to complete heart block will be closely monitored by our maternal fetal medicine specialists in utero to watch for the development of heart failure, and supraventricular tachycardia (SVT) may require treatment before birth.
Typically, mothers are hospitalized to be regularly followed and will be started on drug therapies that help control the fetal heart rate. Our staff will monitor your baby closely during this time as well, and we will help coordinate your delivery plan. After delivery, our team will be there to monitor your newborn to help ensure a healthy start to life.
- Outcomes for Babies with Fetal Arrhythmias
Babies diagnosed with fetal arrhythmias without the presence of congenital heart defects or hydrops, when closely monitored, often have good outcome. Incidents of fetal bradycardia, on the other hand, are associated with a high mortality rate. Congenital heart defects and the presence of fetal hydrops are significant risk factors for pregnancy termination.
Advances in medical technology and therapies arm us with resources to continually improve outcomes for babies with fetal arrhythmias.