What is an arrhythmia?
Almost all heart tissue is capable of starting a heartbeat, or becoming the "pacemaker.” An arrhythmia may occur when the heart's natural pacemaker (the sinus node) develops an abnormal rate or rhythm.
Some arrhythmias are benign (not dangerous), while others may be life threatening. There are different ways of classifying arrhythmias, which can be described based on where within the heart the arrhythmia originates (that is, in the atria or top chambers of the heart, or in the ventricles, or bottom chambers of the heart), or whether the arrhythmia is related to the heart beat being too fast (tachyarrhythmia), too slow (bradyarrhythmia), and whether the beat is regular or irregular (fibrillation).
What is an atrial arrhythmia?
An atrial arrhythmia isan abnormality that occurs in one of the two upper chambers of the heart, the left or right atrium. It is causedby abnormal function of the sinus node or the atrioventricular node.
Types atrial arrhythmias include:
- heart rate varies with breathing
- commonly found in children
- usually a benign condition
- typically no associated symptoms or problems
- sinus tachycardia
sick sinus syndrome
- sinus node sends out electrical signals either too slowly or too fast
premature supraventricular contractions
- also called premature atrial contractions (PAC)
- sinus node or another pacemaker site above the ventricles sends out an electrical signal early
supraventricular tachycardia (SVT)
- also called paroxysmal atrial tachycardia (PAT)
- heart rate speeds up due to a series of early beats from the sinus node or another pacemaker site above the ventricles
- may cause symptoms such as weakness, fatigue, dizziness, fainting or palpitations if the heart rate becomes too fast.
- electrical signals come from the atria at a fast but regular rate, causing the ventricles to contract faster and increase the heart rate
- electrical signals come from the atria at a very fast and erratic rate
What is a ventricular arrhythmia?
A ventricular arrhythmia occurs in the two lower chambers of the heart called the ventricles. It is caused by an interruption in the electrical conduction pathways, or the development of another area within the heart tissue that takes over the function of the sinus node.
Types ventricular arrhythmias include:
Premature ventricular contractions (PVCs)
- Electrical signal originates in the ventricles and causes the ventricles to contract before receiving the electrical signal from the atria.
- They are common and often don’t cause symptoms or problems.
- In some cases, they may cause symptoms such as weakness, fatigue, dizziness, fainting or palpitations.
Ventricular tachycardia (VT)
- Life-threatening condition where an electrical signal is sent from the ventricles at a very fast but even rate.
- It may cause symptoms such as weakness, fatigue, dizziness, fainting or palpitations.
Ventricular fibrillation (VF)
- An electrical signal is sent from the ventricles at a very fast and erratic rate.
- It may cause very low blood pressure and symptoms such as weakness, dizziness, fainting or loss of consciousness.
- A person in VT may require an electric shock or medications to convert the rhythm to back normal sinus rhythm.
What does a heart arrhythmia mean for my child?
Arrhythmias, or irregular heartbeats, can cause problems with contractions of the heart chambers. This can show up in two ways:
- not allowing the chambers to fill with an adequate amount of blood
- not allowing a sufficient amount of blood to be pumped out to the body