Atrial fibrillation (A-fib) is a type of arrhythmia, or irregular heartbeat. It often causes the heart to beat unusually fast. The three main types of atrial fibrillation are: paroxysmal, persistent, and long-term persistent.

Doctors also categorize A-fib as either valvular or nonvalvular.Doctors need to determine the type of atrial fibrillation before they can identify the best treatment.

In some people, A-fib causes no symptoms, and a doctor might only discover it when testing for something else. Whether symptoms are present does not help a doctor classify A-fib. We explore the different types in detail below.

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A paroxysm is a sudden episode of a disease or symptom. Paroxysmal A-fib involves an irregularity in the heartbeat starting suddenly and resolving on its own within 7 days. The episode may only last a few seconds or several hours.

A person with this type of A-fib has no noticeable symptoms and may not need treatment. However, a doctor may prescribe anticoagulation medications to make it harder for the blood to clot. This may help prevent a stroke.

Episodes of this type of A-fib may occur intermittently, at irregular intervals. About half of all A-fib cases are paroxysmal.

Episodes of persistent A-fib are continual and last for more than 7 days.

A person may not need treatment, but they are more likely to need medication or a procedure to restore the heart’s normal rhythm. Medications such as beta-blockers and calcium channel blockers can help control a person’s heart rate. A doctor also typically prescribes anticoagulants to prevent blood clots.

In addition to antiarrhythmic medications, a doctor may recommend a procedure such as cardioversion, which involves using synchronized electric shocks to control the rhythm of the heart. Another option is catheter ablation, in which a surgeon destroys any tissue that may be causing the irregular rhythm.

This refers to A-fib that has lasted for more than 1 year.

If, by this time, medications, cardioversion, catheter ablation, and other techniques are unable to restore a normal rhythm, and it seems unlikely that this will happen, the doctor may recommend ending efforts to control the arrhythmia. If the person agrees to this, the diagnosis becomes “permanent A-fib.”

The doctor might still prescribe medication that aims to control the heart rate and prevent blood clots.

If A-fib is nonvalvular, this means that it does not stem from a problem with a valve of the heart or a replacement valve.

Valvular A-fib results from a problem with a heart valve, such as mitral valve stenosis, in which not enough blood can pass from the left atrium into the left ventricle.

Any type of A-fib can be either valvular or nonvalvular.

It is vital that doctors determine whether a valvular problem is responsible for A-fib before they recommend a treatment plan. Newer medications that aim to prevent blood clots are available, but the Food and Drug Administration (FDA) has not approved them as a safe and effective treatments for nonvalvular A-fib.

Atrial fibrillation is a type of irregular heartbeat. Doctors classify the types of A-fib depending on how long the irregularity in the heartbeat lasts and whether a problem with a valve of the heart is responsible.

Paroxysmal A-fib lasts between a few seconds and 1 week, persistent A-fib lasts longer than 1 week, and long-term persistent A-fib lasts longer than 12 months.