How does the heart beat?
The heartbeat is controlled by small electrical signals in the heart. These electrical signals cause the heart muscle to contract. When the muscle contracts, blood is pumped through the heart.
What is an arrhythmia?
An arrhythmia (also called dysrhythmia) is usually an irregular heartbeat. The heart rate can be fast, slow or irregular, taking into consideration age and activity. For example, a newborn's heart beats much faster than a five-year-old child's heart.
Some children have arrhythmias that cause the heart to beat much faster than normal. This type of arrhythmia is called tachycardia.
Tachycardia can last for seconds, minutes, or even hours. Symptoms can differ for each child.
If your child has a suspected arrhythmia, checking their heart rate regularly at home will help you learn when there is a change from their normal heart rate.
How to listen to your child's heart rate
The best way to listen to your child’s heart rate is with a stethoscope. You can purchase a stethoscope at your local drug store or medical supplies store. Any basic stethoscope will work to listen to your child’s heart rate.
To listen to your child’s heart rate, follow the steps below.
- Place the ear pieces of the stethoscope comfortably in your ears.
- Place the round part over your child’s chest, beneath the left nipple.
- Count for one full minute.
Try to listen when your child is calm (not crying and sitting still).
When to listen to your child's heart rate
For babies and toddlers, listen to your child’s chest regularly to find a "normal" heart rate. Listening at specific times, such as with diaper changes, can help you learn what your child’s heart rate is throughout the day.
Once you have an idea of what your baby or toddler’s normal heart rate is, monitor it daily. You can listen before giving their medication or if you notice a change in their appearance or behaviour.
For older children, find their "normal" heart rate by listening at least twice a day, once in the morning and once at night.
Once you have an idea of what your child’s normal heart rate is throughout the day, you can listen when they are showing signs of a fast heart rate or are complaining of a fast heart rate.
Normal heart rates
Normal heart rates fall into ranges depending on the age of your child. In general, the younger and smaller the child, the higher you would expect the heart rate to be. For example, a newborn’s heart rate can rise to 160 to 180 beats per minute with no cause for concern, particularly if they are upset or active.Normal heart rates fall into ranges depending on the age of your child. In general, the younger and smaller the child, the higher you would expect the heart rate to be.
As your child gets older, their heart rate slows.
A person’s heart rate can also change at different times of the day. During exercise or activity, the heart rate is higher. During sleep, the heart rate is lower.
Sinus arrhythmia
Sometimes, the heart rate can increase and decrease with breathing. This is called sinus arrhythmia and is common in young, healthy children. This does not cause symptoms or need any treatment.
How to tell if your child's heart rate is too fast
The following table provides a guide of what is considered too fast for a resting heart rate. This is a heart rate taken when the child is calm or at rest.
| Age | Resting heart rate of concern |
|---|---|
| Younger than 1 year | More than 180 beats per minute |
| Older than 1 year | More than 150 beats per minute |
A heart rate that is too quick to count is always considered too fast.
Symptoms of fast heart rate
Your child will react to a high heart rate in a way that is unique to them. Some children may not show any symptoms while others may feel dizzy or unwell.
If you are unsure if your child is showing symptoms or if you child is feeling unwell, you can listen to their heart using your stethocope.
The main symptoms of a fast heart rate include:
- Difficult or faster breathing
- Changes in skin colour (pale or blue)
- Lack of energy (lethargy)
Less common symptoms include:
- Lack of appetite
- Vomiting
What to do if your child has a fast heart rate
If you listen to your child’s heart rate and it is "normal", return to regular activity.
If your child's heart rate is fast and your child looks well (comfortable, breathing, alert and normal colour), check the heart rate again in 5-10 minutes. If the heart rate is still fast, continue checking every 5-10 minutes.
If your child’s heart rate is still high after 30 minutes, please contact your child’s cardiology team. This may include contacting the clinic nurse during regular business hours.
When to call 911
Call 911 immediateily if your child looks unwell and has any of the following.
- Trouble breathing
- Change in colour (looks paler or turning blue)
- Loss of consciousness
At SickKids
If your child is a patient at SickKids, contact the cardiology clinic nurse during regular business hours. After hours and on weekends, contact the Cardiac Inpatient Unit (4D Ward) after hours and on weekends.