• A heart arrhythmia is a problem with the rate or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm.
  • Most arrhythmias are harmless, but some can be serious or even life threatening. When the heart rate is too fast, too slow, or irregular, the heart may not be able to pump enough blood to the body.
  • The four main types of arrhythmia are premature (extra) beats, supraventricular arrhythmias, ventricular arrhythmias, and bradyarrhythmias.
  • An arrhythmia can occur if the electrical signals that control the heartbeat are delayed or blocked, or if the heart produces extra electrical signals. Other causes of arrhythmia include smoking, heavy alcohol use, use of certain drugs and medicines, too much caffeine or nicotine, strong emotional stress or anger, and underlying medical conditions. Sometimes the cause of an arrhythmia cannot be found.
  • Most arrhythmias cause no signs or symptoms. When signs and symptoms are present, the most common ones are heart palpitations, a slow heartbeat, an irregular heartbeat, and feeling pauses between heartbeats.
  • Common arrhythmia treatments include medicines, medical procedures, and surgery. Treatment is needed when an arrhythmia causes serious symptoms, such as dizziness, chest pain, or fainting.
  • Because many arrhythmias are caused by underlying heart disease, it's important to keep your heart healthy. Follow a healthy diet, get physical activity regularly, quit smoking, maintain a healthy weight, and keep your blood cholesterol and blood pressure at healthy levels. Try to manage stress and anger.

What Causes an Arrhythmia?

Each heart beat is triggered by an electrical signal that begins in a group of cells called the sinus node or sinoatrial (SA) node. From the SA node, the electrical signal travels through special pathways in the right and left atria. The electrical signal then moves down to a group of cells called the atrioventricular (AV) node. The electrical signal then leaves the AV node and travels along a pathway called the bundle of His. This pathway divides into a right bundle branch and a left bundle branch.

The ventricles then relax, and the heartbeat process starts all over again in the SA node.

A problem with any part of this process can cause an arrhythmia. For example, in atrial fibrillation, a common type of arrhythmia, electrical signals travel through the atria in a fast and disorganized way. This causes the atria to quiver instead of contract.

Who Is At Risk for an Arrhythmia?

Arrhythmias are more common in people who have diseases or conditions that weaken the heart, such as:

  • Heart attack
  • Heart failure or cardiomyopathy
  • Heart valve disorders
  • Congenital heart defects
  • Heart tissue that's too thick or stiff or that hasn't formed normally

Other conditions also can increase the risk for arrhythmias, such as:

  • High blood pressure
  • Infections that damage the heart muscle or the sac around the heart
  • Diabetes, which increases the risk of high blood pressure and coronary heart disease
  • Sleep apnea (when breathing becomes shallow or stops during sleep), which can stress the heart because the heart doesn't get enough oxygen
  • An overactive or underactive thyroid gland (too much or too little thyroid hormone in the body)

Also, several other risk factors can increase risk for arrhythmias. Examples include heart surgery, certain drugs (such as cocaine or amphetamines), or an imbalance of chemicals or other substances (such as potassium) in the bloodstream.

Reference: The National Heart, Blood, and Lung Institute.

Last updated April 16, 2017

This information is for general educational uses only. It may not apply to you and your personal medical needs. This information should not be used in place of a visit, call, consultation with or the advice of your physician or health care professional.

Communicate promptly with your physician or other health care professional with any health-related questions or concerns.

Be sure to follow specific instructions given to you by your physician or health care professional.

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