In general, heart arrhythmias are grouped by the speed of the heart rate. For example:
- Tachycardia (tak-ih-KAHR-dee-uh) is a fast heart. The resting heart rate is greater than 100 beats a minute.
- Bradycardia (brad-e-KAHR-dee-uh) is a slow heartbeat. The resting heart rate is less than 60 beats a minute.
Fast heartbeat (tachycardia)
Types of tachycardias include:
- Atrial fibrillation (A-fib). Chaotic heart signaling causes a rapid, uncoordinated heart rate. The condition may be temporary, but some A-fib episodes may not stop unless treated. A-fib is associated with serious complications such as stroke.
- Atrial flutter. Atrial flutter is similar to A-fib, but heartbeats are more organized. Atrial flutter is also linked to stroke.
- Supraventricular tachycardia. Supraventricular tachycardia is a broad term that includes arrhythmias that start above the lower heart chambers (ventricles). Supraventricular tachycardia causes episodes of a pounding heartbeat (palpitations) that begin and end abruptly.
- Ventricular fibrillation. This type of arrhythmia occurs when rapid, chaotic electrical signals cause the lower heart chambers (ventricles) to quiver instead of contacting in a coordinated way that pumps blood to the rest of the body. This serious problem can lead to death if a normal heart rhythm isn’t restored within minutes. Most people who have ventricular fibrillation have an underlying heart disease or have experienced serious trauma.
- Ventricular tachycardia. This rapid, regular heart rate starts with faulty electrical signals in the lower heart chambers (ventricles). The rapid heart rate doesn’t allow the ventricles to properly fill with blood. As a result, the heart can’t pump enough blood to the body. Ventricular tachycardia may not cause serious problems in people with an otherwise healthy heart. In those with heart disease, ventricular tachycardia can be a medical emergency that requires immediate medical treatment.