A heart arrhythmia (uh-RITH-me-uh) is an irregular heartbeat. A heart arrhythmia happens when the electrical signals that tell the heart to beat don't work as they should. The heart may beat too fast or too slow. Or the pattern of the heartbeat may be inconsistent.
A heart arrhythmia may feel like a fluttering, pounding or racing heartbeat. Some heart arrhythmias are harmless. Others may cause life-threatening symptoms.
There are times when it is OK to have a fast or slow heartbeat. For example, the heart may beat faster with exercise or slow down during sleep.
Heart arrhythmia treatment may include medicines, devices such as pacemakers, or a procedure or surgery. The goals of treatment are to control or get rid of fast, slow or otherwise irregular heartbeats. A heart-healthy lifestyle can help prevent heart damage that can trigger some heart arrhythmias.
Another name for heart arrhythmia is cardiac arrhythmia.
Types
In general, heart arrhythmias are grouped by the speed of the heart rate. For example:
- Tachycardia (tak-ih-KAHR-dee-uh) is a fast heartbeat. The heart rate is greater than 100 beats a minute.
- Bradycardia (brad-e-KAHR-dee-uh) is a slow heartbeat. The heart rate is less than 60 beats a minute.
Fast heartbeat, called tachycardia
Types of tachycardias include:
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Atrial fibrillation , also called AFib. Chaotic heart signaling causes an irregular and often very fast heartbeat. AFib may be temporary and start and stop on its own. Sometimes the irregular heartbeat may not stop unless treated. AFib has been linked to stroke.
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Atrial flutter. Atrial flutter is similar to AFib, but the heartbeats are more organized. Atrial flutter also is linked to stroke.
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Supraventricular tachycardia. This broad term includes irregular heartbeats that start above the lower heart chambers, called the ventricles. Supraventricular tachycardia causes a pounding heartbeat that starts and stops suddenly.
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Ventricular fibrillation.
Rapid, chaotic electrical signals cause the lower heart chambers to tremble instead of squeezing in a coordinated way. This serious heart condition can lead to death if the heart isn't reset to a regular heart rhythm within minutes. Most people with ventricular fibrillation have an underlying heart disease or had a serious injury.
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Ventricular tachycardia. This rapid, irregular heartbeat starts with faulty electrical signals in the lower heart chambers, called the ventricles. The rapid heartbeat doesn't let the ventricles properly fill with blood. So the heart may not be able to pump enough blood to the body. Ventricular tachycardia may not cause serious concerns in people with otherwise healthy hearts. In those with heart disease, ventricular tachycardia can be an emergency that needs medical care right away.
Slow heartbeat, called bradycardia
A heart rate below 60 beats a minute is called bradycardia. But a low resting heart rate doesn't always mean there's trouble with the heart. If you're physically fit, your heart may be able to pump enough blood to the body with less than 60 beats a minute.
If you have a slow heart rate and your heart isn't pumping enough blood, you may have a type of bradycardia. Types of bradycardias include:
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Sick sinus syndrome. The sinus node sets the pace of the heart. If the node doesn't work as it should, the heartbeat may switch between too slow and too fast. Sick sinus syndrome can be caused by scarring near the sinus node that slows, disrupts or blocks heartbeat signals. The condition is most common among older adults.
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Conduction block. A block of the heart's electrical pathways can cause the signals that trigger the heartbeats to slow down or stop. Some blocks may cause no symptoms. Others may cause skipped beats or slowed heartbeats.
Premature heartbeats
Premature heartbeats are extra beats that occur one at a time. Sometimes they happen in patterns that alternate with a regular heartbeat.
- If the extra beats come from the top chamber of the heart, they are called premature atrial contractions. Your healthcare team may call them PACs.
- If they come from the bottom chamber, they are called premature ventricular contractions. You may hear them called PVCs.
A premature heartbeat may feel like your heart skipped a beat. These extra beats are generally not a concern. They rarely mean you have a more serious condition. Still, a premature beat can trigger an irregular heartbeat that lasts a long time, especially in people with heart disease. Sometimes, having very frequent premature ventricular beats may lead to a weak heart.
Premature heartbeats may occur at rest. Stress, heavy exercise and the use of stimulants, such as caffeine or nicotine, also may cause premature heartbeats.