Understanding Atrial Fibrillation

An arrhythmia is any problem with the speed or pattern of the heartbeat. Atrial fibrillation (AFib) is the most common type of arrhythmia. It causes fast, chaotic electrical signals in the atria. This makes it hard for the heart to work as it should. 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. This is called paroxysmal. Or it may continue for longer periods and need treatment. This is called persistent.

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

Cross section of heart showing atrial fibrillation.

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. This 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:

  • Older age

  • 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, healthcare providers don't know the cause.

What are the symptoms of atrial fibrillation?

AFib 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

    • Blood thinners or anti-clotting medicines to help reduce the risk for blood clots and stroke

  • Left atrial appendage closure. Your healthcare provider may advise this device to prevent stroke. You may need it if you are at high risk for stroke but have problems taking blood-thinner (anticoagulant) medicines. The device is placed in the part of the heart where most clots form. This area is called the left atrial appendage (LAA). It's a pouch-like structure in the muscle wall of the left atrium. The device closes off the LAA to prevent clots moving from the heart to the brain and causing a stroke. This is a nonsurgical procedure done through a catheter in the groin.

  • 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 (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 an AV node 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. Most often, the left atrial appendage is closed off as well.

  • Hybrid surgical-catheter ablation for AFib. This treatment is used for people with AFib that continues or is hard to treat. It combines surgery with a catheter ablation. During the surgery, the surgeon makes small cuts (incisions) between the ribs in the chest or in the abdomen near the sternum. The surgeon puts a scope through the incisions to get to the backside and other areas of the heart. This is to deliver energy to the surface of the atria and disrupt the abnormal electrical signals. The catheter portion of the procedure is done by putting a catheter into a vein in the groin. The catheter is guided to the inside of the heart. Using the catheter, radiofrequency ablation is done to destroy additional tissue inside the heart that is causing the AFib. It's also done to assess the success of the surgical lesions. Using both of these approaches may work better to block the abnormal electrical signals and be a more permanent treatment for persistent AFib.

What are possible complications of atrial fibrillation?

Complications can include:

  • Blood clots

  • Stroke

  • Dementia

  • 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

© 2000-2022 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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