Supraventricular Tachycardia in Children: What You Need to Know
A top-end heart rate for children is roughly 220 bpm minus the child’s age in years. Rates faster than that can indicate supraventricular tachycardia (SVT), an abnormally fast heart rhythm caused by an electrical short circuit in the top chambers of the heart or with an extra electrical pathway connecting the bottom and top of the heart. SVT is The most common tachycardia in children.
SVT is a highly treatable condition that can be treated safely and effectively in children. “In general, SVT is not life-threatening,” said Peter Fischbach, MD, Pediatric Cardiologist at Children’s Healthcare of Atlanta Cardiology. “It’s mostly just disconcerting and uncomfortable. It’s the unpleasant feeling of having a racing heart rate that you can’t stop.”
How SVT Develops
The pathways in the heart that support SVT are usually present just as a mother is finding out she is pregnant, at about 8–10 weeks of gestation. However, just having these abnormal pathways doesn’t mean that a person will develop SVT.
The faster-than-normal heart rate can appear in utero or at any point in life, and doctors are not entirely sure why this occurs. SVT in children is not caused by bad genes or environmental exposures, although some stimulants and street drugs can lead to abnormal heart rhythms.
SVT may also be associated with chronic heart disease due to the need for complex surgeries in some children. While SVT can be disruptive, it is not associated with catastrophic events such as sudden cardiac death in young athletes.
SVT in Infants and Children
Children who are diagnosed with neonatal SVT (occurring within the first month of life) often stop having episodes by their first birthday. However, there is about a 50% chance of recurrence when the child reaches school age.
If SVT is first diagnosed after the neonatal period, there is an 80–85% chance that it will become a chronic condition.
SVT is usually well tolerated in infants and babies. Because they cannot describe what they are feeling, it may not be obvious that a baby has SVT. If SVT persists for 24–36 hours, the baby’s heart can become tired, which may cause them to appear pale, fatigued, or uninterested in eating.
“The good news is that when the tachycardia is corrected, the baby recovers completely, and all those symptoms resolve,” Dr. Fischbach said.
Treatment Options for SVT in Children
Three treatment options are available for children diagnosed with SVT:
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Observation
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Chronic medication
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Catheter ablation
To treat SVT acutely, patients can sometimes slow their heart rate using vagal maneuvers, such as:
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Holding their breath
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Standing on their head
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Applying ice to the face
These maneuvers can activate the “brake pedal” on the heart, interrupting the electrical short circuit that acts like a “gas pedal.”
There are also medications that can correct SVT quickly (given by IV) or be taken chronically to prevent future episodes. If medications don’t work or cause unpleasant side effects, catheter ablation may be recommended—typically for children at least 8 years old.
Advances in Pediatric Electrophysiology
The field of electrophysiology and the treatment of SVT has evolved dramatically. Routine outpatient catheter ablation procedures are now considered the treatment of choice for many children over age 8.
Children’s Healthcare of Atlanta has been at the forefront of these advances in recent years. In the past, patients often had to live with SVT indefinitely, but today, ablation offers a permanent cure with minimal procedural risk.
“One of the reasons I love electrophysiology is that we are dealing with a fixable problem,” Dr. Fischbach said. “Patients can go home completely cured and don’t have problems in the future. There are very few places in pediatric cardiology where you can completely eliminate the problem the patient is having.”
Contributing Cardiologist: Peter Fischbach, MD
Related:
CHDs Can Show Up in Teens, the Heart Center is There to Help
The American Heart Association
The Pediatric & Congenital Electrophysiology Society (PACES)
Arrhythmia and Electrophysiology Program
For more information about Children’s Healthcare of Atlanta Cardiology and our pediatric cardiology specialists, click here.