An arrhythmia is an abnormal rhythm of the heart, which can cause the heart to pump less effectively. It most often occurs in adults, but can also occur in children.
Some arrhythmias are not dangerous, while others can be life threatening.
Arrhythmias are classified by the area of the heart where they start: the upper chambers (atria) or lower chambers (ventricles). They can be related to the heart beating too fast (tachycardia), too slow (bradycardia), or in an irregular pattern (fibrillation).
There are many types of arrhythmias, including:
- Long QT syndrome (LQTS). LQTS occurs when the ventricles take too long to contract and release. This can cause fast, erratic heartbeats.
- Sinus tachycardia. A sinus tachycardia is a normal increase in the heart rate that’s common in children. It most often occurs with exercise, fever, or excitement and usually doesn’t need treatment.
- Supraventricular tachycardia (SVT), also called paroxysmal atrial tachycardia (PAT). This is the most common type of tachycardia in children. It occurs when the electrical signals from the heart’s atria fire abnormally, causing a fast heartbeat.
- Sick sinus syndrome. Occurs when the sinus node in the heart doesn’t fire properly and the heartbeat slows down. It can sometimes occur in children who have had open-heart surgery.
- Catecholaminergic polymorphic ventricular tachycardia (CPVT). This is a rare inherited cardiac condition. These abnormal rhythms most often occur at times of high adrenaline levels, such as during exercise or strong emotion. Left untreated, CPVT can cause the heart to stop beating.
- Premature ventricular contractions (PVC) or premature atrial contractions (PAC). These are caused when an extra or premature heartbeat occurs, either in the atria or ventricles. They are common in children and teens and usually need no treatment.
- Atrial flutter. This is a very fast heartbeat caused when the muscles in the atria contract quickly.
- Atrial fibrillation (AFib). AFib is rare in children. It occurs when the electrical signals that firing in or around the heart cause the atria to quiver, or fibrillate. This causes the ventricles to then contract at an abnormal rate and work less effectively.
- Ventricular tachycardia (VT). This is an uncommon, but serious and potentially life-threatening condition. It is caused by a very fast electrical signal that starts in the ventricles. In some cases, it is caused by serious heart disease.
- Wolff-Parkinson-White (WPW) syndrome. WPW is a malfunction of the electrical pathways between the atria and ventricles, causing the signals to signal that gets to the ventricle over an extra electrical pathway. It's present since birth. A fast heart rate is a common symptom. Or a child may not have symptoms. Sudden cardiac death may rarely occur.
- Complete heart block. Heart block occurs when the electrical signal from the atria to the ventricles is blocked. This causes the heart to beat more slowly. Complete heart block may be caused by heart disease or happen after heart surgery.
