Medical Conditions

Wolff-Parkinson-White (WPW) Syndrome in Babies

Medically reviewed by Dr. Michael Okonkwo, MD, FAAP · Board-Certified Neonatologist

Content reviewed against published AHA, AAP, Mayo Clinic guidelines

Editorial policy

Last reviewed:

If your baby has been diagnosed with or you suspect wolff-parkinson-white (wpw) syndrome in babies, here is what the evidence says.

The short answer

Wolff-Parkinson-White (WPW) syndrome is a heart condition where an extra electrical pathway exists between the upper and lower chambers of the heart. This extra pathway can cause episodes of supraventricular tachycardia (SVT), where the heart beats very rapidly. In infants, WPW is the most common identifiable cause of SVT. It is often detected on an ECG showing a characteristic "delta wave" pattern. Many infants with WPW outgrow their episodes by 1 year of age, but ongoing monitoring by a pediatric cardiologist is important.

Key takeaways

  • Wolff-Parkinson-White (WPW) syndrome is a heart condition where an extra electrical pathway exists between the upper and lower chambers of the heart. This extra pathway can cause episodes of supraventricular tachycardia (SVT), where the heart beats very rapidly. In infants, WPW is the most common identifiable cause of SVT. It is often detected on an ECG showing a characteristic "delta wave" pattern. Many infants with WPW outgrow their episodes by 1 year of age, but ongoing monitoring by a pediatric cardiologist is important.
  • Usually normal when: Your baby's heart rate increases with crying, feeding, or activity and returns to normal quickly
  • Call your doctor if: Your baby has a sustained episode of very rapid heartbeat with pallor, lethargy, poor feeding, or rapid breathing -- go to the emergency room immediately
  • Varies by age — see the age-by-age breakdown below
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What Parents Should Know

According to AHA, AAP, Mayo Clinic guidelines, wolff-Parkinson-White (WPW) syndrome is a heart condition where an extra electrical pathway exists between the upper and lower chambers of the heart. This extra pathway can cause episodes of supraventricular tachycardia (SVT), where the heart beats very rapidly. In infants, WPW is the most common identifiable cause of SVT. It is often detected on an ECG showing a characteristic "delta wave" pattern. Many infants with WPW outgrow their episodes by 1 year of age, but ongoing monitoring by a pediatric cardiologist is important. At 0-3 months, wPW may be detected prenatally when fetal tachycardia is identified, or in the newborn period when an ECG is performed for a fast heart rate. Newborns with WPW-related SVT may present with irritability, poor feeding, pallor, or rapid breathing. The heart rate during an SVT episode can exceed 220 bpm. Episodes may be brief or sustained. If SVT is prolonged and unrecognized, it can lead to heart failure in infants. Medication is typically started to prevent recurrent episodes. It is generally considered normal when your baby's heart rate increases with crying, feeding, or activity and returns to normal quickly. However, you should contact your pediatrician promptly if your baby has a sustained episode of very rapid heartbeat with pallor, lethargy, poor feeding, or rapid breathing -- go to the emergency room immediately.

Sources: [1], [2], [3]

Normal vs. Concerning

Usually Normal
Worth Discussing
Your baby's heart rate increases with crying, feeding, or activity and returns to normal quickly
Your baby has a sustained episode of very rapid heartbeat with pallor, lethargy, poor feeding, or rapid breathing -- go to the emergency room immediately
Your child was found to have WPW pattern on ECG but has never had symptoms (asymptomatic WPW)
Your child loses consciousness or faints during physical activity or excitement -- call 911
Your baby had WPW-related SVT as a newborn but has had no episodes for several months while on preventive medication
An SVT episode in your child does not resolve with vagal maneuvers (such as applying ice to the face for an infant) within 10-15 minutes -- seek emergency care
An ECG shows the WPW pattern has resolved, suggesting the accessory pathway is no longer conducting
Your baby has occasional brief episodes of appearing pale or fussy that resolve on their own within a few minutes

When to Seek Immediate Care

  • Your baby has a sustained episode of very rapid heartbeat with pallor, lethargy, poor feeding, or rapid breathing -- go to the emergency room immediately
  • Your child loses consciousness or faints during physical activity or excitement -- call 911
  • An SVT episode in your child does not resolve with vagal maneuvers (such as applying ice to the face for an infant) within 10-15 minutes -- seek emergency care

By Age

What to expect by age

0-3 months

WPW may be detected prenatally when fetal tachycardia is identified, or in the newborn period when an ECG is performed for a fast heart rate. Newborns with WPW-related SVT may present with irritability, poor feeding, pallor, or rapid breathing. The heart rate during an SVT episode can exceed 220 bpm. Episodes may be brief or sustained. If SVT is prolonged and unrecognized, it can lead to heart failure in infants. Medication is typically started to prevent recurrent episodes.

3-12 months

Infants in this age range may continue to have SVT episodes related to their WPW. Parents may notice sudden pallor, irritability, or sweating. Some infants are on daily preventive medications such as beta-blockers or flecainide. Many infants with WPW see their episodes decrease significantly by the time they approach their first birthday. The accessory pathway may become dormant as the heart grows, though it can reactivate later in childhood.

1-3 years

Many children who had WPW-related SVT as infants experience a quiescent period during toddlerhood. Preventive medications may be tapered under cardiologist guidance. However, some children continue to have breakthrough episodes. Toddlers may show signs like sudden stopping of play, clutching their chest, or appearing frightened. Regular follow-up with a pediatric cardiologist is important to monitor the ECG pattern and decide on ongoing management.

3+ years

WPW can recur in older children, particularly during exercise or emotional excitement. Children who can describe symptoms may report a racing heart, dizziness, or chest fluttering. For children with recurrent symptomatic WPW, catheter ablation of the accessory pathway is a highly effective procedure, typically considered after age 5-7 or when the child is large enough for the procedure. Ablation has a success rate of over 95% and can be curative.

What to Tell Your Pediatrician

  • Describe when you first noticed wolff-parkinson-white (wpw) syndrome in babies and how it has changed over time.
  • Note your baby's current age and which age-specific patterns you are seeing.
  • Mention if your baby has occasional brief episodes of appearing pale or fussy that resolve on their own within a few minutes.
  • Mention if your child with known WPW has not had a cardiology follow-up in over 6 months.
  • Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
  • Bring a list of any questions or observations you want to discuss at the appointment.

What Should You Do?

When to take action

Probably normal when...
  • Your baby's heart rate increases with crying, feeding, or activity and returns to normal quickly
  • Your child was found to have WPW pattern on ECG but has never had symptoms (asymptomatic WPW)
  • Your baby had WPW-related SVT as a newborn but has had no episodes for several months while on preventive medication
  • An ECG shows the WPW pattern has resolved, suggesting the accessory pathway is no longer conducting
Mention at your next visit when...
  • Your baby has occasional brief episodes of appearing pale or fussy that resolve on their own within a few minutes
  • Your child with known WPW has not had a cardiology follow-up in over 6 months
  • Your child seems to tire more easily than peers or avoids physical activity
Act now when...
  • Your baby has a sustained episode of very rapid heartbeat with pallor, lethargy, poor feeding, or rapid breathing -- go to the emergency room immediately
  • Your child loses consciousness or faints during physical activity or excitement -- call 911
  • An SVT episode in your child does not resolve with vagal maneuvers (such as applying ice to the face for an infant) within 10-15 minutes -- seek emergency care

What You Can Do at Home

  • Keep track of when you notice wolff-parkinson-white (wpw) syndrome in babies — noting the time of day, duration, and any triggers can help your pediatrician.
  • Remember that your baby's heart rate increases with crying, feeding, or activity and returns to normal quickly — this is generally within the range of normal.
  • At 0-3 months, focus on observation rather than intervention unless your pediatrician advises otherwise.
  • Follow any care instructions from your pediatrician. Keep a written log of symptoms to bring to appointments.
  • While monitoring at home, seek immediate care if your baby has a sustained episode of very rapid heartbeat with pallor, lethargy, poor feeding, or rapid breathing -- go to the emergency room immediately.

Supraventricular Tachycardia (SVT) in Babies

Supraventricular tachycardia (SVT) is the most common abnormal heart rhythm in infants and children. During an episode, the heart rate can reach 220-300 beats per minute in infants, compared to a normal rate of 100-160. Babies may become pale, irritable, or lethargic, and may feed poorly. Most episodes can be stopped with vagal maneuvers or medication, and many children outgrow SVT by age 1. If your baby appears pale, fussy, or you feel an extremely fast heartbeat, seek immediate medical attention.

Congenital Heart Defect Signs in Babies

Congenital heart defects (CHDs) are the most common type of birth defect, affecting about 1 in 100 babies. They range from small holes in the heart that may close on their own to complex defects requiring multiple surgeries. Early detection through pulse oximetry screening and recognizing key signs — such as blue skin, rapid breathing, poor feeding, and failure to gain weight — is critical. Advances in surgery have dramatically improved survival and quality of life.

Baby Heart Murmur - Innocent vs Concerning

Heart murmurs are very common in children - up to 75% of children will have an audible murmur at some point. The vast majority are "innocent" or "functional" murmurs, meaning there is no structural heart problem. These murmurs are simply the sound of blood flowing normally through the heart and are more audible during fever, illness, or excitement. A smaller number of murmurs indicate a structural heart difference that may need monitoring or treatment. Your pediatrician can usually distinguish between the two and will refer for an echocardiogram if there is any concern.

Milestone

Month-by-Month Development

Detailed monthly development guides from birth through 24 months.

Guide

When to Call the Doctor

General guide on when to call the pediatrician, visit urgent care, or go to the ER.

Frequently asked questions

Is wolff-parkinson-white (wpw) syndrome in babies normal?
Wolff-Parkinson-White (WPW) syndrome is a heart condition where an extra electrical pathway exists between the upper and lower chambers of the heart. This extra pathway can cause episodes of supraventricular tachycardia (SVT), where the heart beats very rapidly. In infants, WPW is the most common identifiable cause of SVT. It is often detected on an ECG showing a characteristic "delta wave" pattern. Many infants with WPW outgrow their episodes by 1 year of age, but ongoing monitoring by a pediatric cardiologist is important.
When should I call the doctor about wolff-parkinson-white (wpw) syndrome in babies?
Your baby has a sustained episode of very rapid heartbeat with pallor, lethargy, poor feeding, or rapid breathing -- go to the emergency room immediately Your child loses consciousness or faints during physical activity or excitement -- call 911 An SVT episode in your child does not resolve with vagal maneuvers (such as applying ice to the face for an infant) within 10-15 minutes -- seek emergency care
When is wolff-parkinson-white (wpw) syndrome in babies normal?
Your baby's heart rate increases with crying, feeding, or activity and returns to normal quickly Your child was found to have WPW pattern on ECG but has never had symptoms (asymptomatic WPW) Your baby had WPW-related SVT as a newborn but has had no episodes for several months while on preventive medication
What causes wolff-parkinson-white (wpw) syndrome in babies?
Wolff-Parkinson-White (WPW) syndrome is a heart condition where an extra electrical pathway exists between the upper and lower chambers of the heart. This extra pathway can cause episodes of supraventricular tachycardia (SVT), where the heart beats very rapidly. In infants, WPW is the most common identifiable cause of SVT. It is often detected on an ECG showing a characteristic "delta wave" pattern. Many infants with WPW outgrow their episodes by 1 year of age, but ongoing monitoring by a pediatric cardiologist is important. Common explanations include: Your baby's heart rate increases with crying, feeding, or activity and returns to normal quickly. Your child was found to have WPW pattern on ECG but has never had symptoms (asymptomatic WPW).
What should I mention to my pediatrician about wolff-parkinson-white (wpw) syndrome in babies?
You should mention wolff-parkinson-white (wpw) syndrome in babies at your next visit if: Your baby has occasional brief episodes of appearing pale or fussy that resolve on their own within a few minutes. Your child with known WPW has not had a cardiology follow-up in over 6 months. Your child seems to tire more easily than peers or avoids physical activity.
Is wolff-parkinson-white (wpw) syndrome in babies normal at 0-3 months?
WPW may be detected prenatally when fetal tachycardia is identified, or in the newborn period when an ECG is performed for a fast heart rate. Newborns with WPW-related SVT may present with irritability, poor feeding, pallor, or rapid breathing. The heart rate during an SVT episode can exceed 220 bpm. Episodes may be brief or sustained. If SVT is prolonged and unrecognized, it can lead to heart failure in infants. Medication is typically started to prevent recurrent episodes.
Is wolff-parkinson-white (wpw) syndrome in babies normal at 3-12 months?
Infants in this age range may continue to have SVT episodes related to their WPW. Parents may notice sudden pallor, irritability, or sweating. Some infants are on daily preventive medications such as beta-blockers or flecainide. Many infants with WPW see their episodes decrease significantly by the time they approach their first birthday. The accessory pathway may become dormant as the heart grows, though it can reactivate later in childhood.
Should I go to the ER for wolff-parkinson-white (wpw) syndrome in babies?
Seek emergency care if your baby has a sustained episode of very rapid heartbeat with pallor, lethargy, poor feeding, or rapid breathing -- go to the emergency room immediately, or if your child loses consciousness or faints during physical activity or excitement -- call 911. When in doubt, call your pediatrician's after-hours line for guidance.
Does wolff-parkinson-white (wpw) syndrome in babies go away on its own?
In many cases, wolff-parkinson-white (wpw) syndrome in babies resolves on its own, especially when your baby's heart rate increases with crying, feeding, or activity and returns to normal quickly. By 3+ years, wPW can recur in older children, particularly during exercise or emotional excitement. Children who can describe symptoms may report a racing heart, dizziness, or chest fluttering. For children with recurrent symptomatic WPW, catheter ablation of the accessory pathway is a highly effective procedure, typically considered after age 5-7 or when the child is large enough for the procedure. Ablation has a success rate of over 95% and can be curative.
AHAAAPMAYO CLINIC

References

  1. [1]American Heart Association. Wolff-Parkinson-White Syndrome (WPW). AHA, 2024. AHA
  2. [2]American Academy of Pediatrics. Arrhythmias in Children. HealthyChildren.org. AAP
  3. [3]Mayo Clinic. Wolff-Parkinson-White (WPW) Syndrome: Symptoms and Causes. Mayo Clinic

Doctor Visit Checklist

Bring this checklist to your next pediatrician visit to discuss Wolff-Parkinson-White (WPW) Syndrome in Babies.

Things to mention

  • Describe when you first noticed wolff-parkinson-white (wpw) syndrome in babies and how it has changed over time.
  • Note your baby's current age and which age-specific patterns you are seeing.
  • Mention if your baby has occasional brief episodes of appearing pale or fussy that resolve on their own within a few minutes.
  • Mention if your child with known WPW has not had a cardiology follow-up in over 6 months.
  • Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
  • Bring a list of any questions or observations you want to discuss at the appointment.

Observations to share

  • Your baby has occasional brief episodes of appearing pale or fussy that resolve on their own within a few minutes
  • Your child with known WPW has not had a cardiology follow-up in over 6 months
  • Your child seems to tire more easily than peers or avoids physical activity

Urgent signs to report immediately

  • Your baby has a sustained episode of very rapid heartbeat with pallor, lethargy, poor feeding, or rapid breathing -- go to the emergency room immediately
  • Your child loses consciousness or faints during physical activity or excitement -- call 911
  • An SVT episode in your child does not resolve with vagal maneuvers (such as applying ice to the face for an infant) within 10-15 minutes -- seek emergency care

My notes

From ismybabyalright.com — free, evidence-based baby health guides

All content follows our editorial policy and is reviewed against published clinical guidelines.

2,705 evidence-based guides6 authoritative medical sources5 medical advisory board members

Related Resources

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Bottom line

Most cases of wolff-parkinson-white (wpw) syndrome in babies are normal. Talk to your pediatrician if your baby has a sustained episode of very rapid heartbeat with pallor, lethargy, poor feeding, or rapid breathing -- go to the emergency room immediately.

Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.

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Supraventricular Tachycardia (SVT) in Babies

Supraventricular tachycardia (SVT) is the most common abnormal heart rhythm in infants and children. During an episode, the heart rate can reach 220-300 beats per minute in infants, compared to a normal rate of 100-160. Babies may become pale, irritable, or lethargic, and may feed poorly. Most episodes can be stopped with vagal maneuvers or medication, and many children outgrow SVT by age 1. If your baby appears pale, fussy, or you feel an extremely fast heartbeat, seek immediate medical attention.

Congenital Heart Defect Signs in Babies

Congenital heart defects (CHDs) are the most common type of birth defect, affecting about 1 in 100 babies. They range from small holes in the heart that may close on their own to complex defects requiring multiple surgeries. Early detection through pulse oximetry screening and recognizing key signs — such as blue skin, rapid breathing, poor feeding, and failure to gain weight — is critical. Advances in surgery have dramatically improved survival and quality of life.

Baby Heart Murmur - Innocent vs Concerning

Heart murmurs are very common in children - up to 75% of children will have an audible murmur at some point. The vast majority are "innocent" or "functional" murmurs, meaning there is no structural heart problem. These murmurs are simply the sound of blood flowing normally through the heart and are more audible during fever, illness, or excitement. A smaller number of murmurs indicate a structural heart difference that may need monitoring or treatment. Your pediatrician can usually distinguish between the two and will refer for an echocardiogram if there is any concern.

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