Atrial fibrillation is a type of arrhythmia, or irregular heartbeat. It often causes the heart to beat unusually fast. Doctors need to determine the type of atrial fibrillation before they can identify the best treatment.

The three main types of atrial fibrillation (A-fib) are: paroxysmal, persistent, and long-term persistent. Doctors also categorize A-fib as either valvular or nonvalvular.

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.