Understanding Atrial Fibrillation

Cross section of heart showing atrial fibrillation.

An arrhythmia is any problem with the speed or pattern of the heartbeat. Atrial fibrillation (AFib) is a common type of arrhythmia. It causes fast, chaotic electrical signals in the atria. This leads to poor functioning of the heart. It also affects how much blood your heart can pump out to the body.

Afib may occur once in a while and go away on its own. Or it may continue for longer periods and need treatment.

AFib can lead to serious problems, such as stroke. Your healthcare provider will need to monitor and manage it.

What happens during atrial fibrillation? 

The heart has an electrical system that sends signals to control the heartbeat. As signals move through the heart, they tell the heart’s upper chambers (atria) and lower chambers (ventricles) when to squeeze (contract) and relax. This lets blood move through the heart and out to the body and lungs.

With AFib, the atria receive abnormal signals. This causes them to contract in a fast and irregular way, and out of sync with the ventricles. When this happens, the atria also have a harder time moving blood into the ventricles. Blood may then pool in the atria, which increases the risk for blood clots and stroke. The ventricles also may contract too quickly and irregularly. As a result, they may not pump blood to the body and lungs as well as they should. This can weaken the heart muscle over time and cause heart failure.

What causes atrial fibrillation?

AFib is more common in older adults. It has many possible causes including:

  • Coronary artery disease

  • Heart valve disease

  • Heart attack

  • Heart surgery

  • High blood pressure

  • Thyroid disease

  • Diabetes

  • Lung disease

  • Sleep apnea

  • Heavy alcohol use

In some cases of AFib, doctors do not know the cause.

What are the symptoms of atrial fibrillation?

AFib may or may not cause symptoms. If symptoms do occur, they may include:

  • A fast, pounding, irregular heartbeat

  • Shortness of breath

  • Tiredness

  • Dizziness or fainting

  • Chest pain

How is atrial fibrillation treated?

Treatments for AFib can include any of the options below.

  • Medicines. You may be prescribed:

    • Heart rate medicines to help slow down the heartbeat

    • Heart rhythm medicines to help the heart beat more regularly

    • Anti-clotting medicines to help reduce the risk for blood clots and stroke

  • Electrical cardioversion. Your healthcare provider uses special pads or paddles to send one or more brief electrical shocks to the heart. This can help reset the heartbeat to normal.

  • Ablation. Long, thin tubes called catheters are threaded through a blood vessel to the heart. There, the catheters send out hot or cold energy to the areas causing the abnormal signals. This energy destroys the problem tissue or cells. This improves the chances that your heart will stay in normal rhythm without using medicines. If your heart rate and rhythm can’t be controlled, you may need ablation and a pacemaker. These will help control the heart rate and regularity of the heartbeat.

  • Surgery. During surgery, your healthcare provider may use different methods to create scar tissue in the areas of the heart causing the abnormal signals. The scar tissue disrupts the abnormal signals and may stop AFib from occurring.

What are the complications of atrial fibrillation?

These can include:

  • Blood clots

  • Stroke

  • Heart failure. This problem occurs when the heart muscle weakens so much that it can no longer pump blood well.

When should I call my healthcare provider?

Call your healthcare provider right away if you have any of these:

  • Symptoms that don’t get better with treatment, or get worse

  • New symptoms