What happens during atrial fibrillation? 

The heart has an electrical system. This sends signals to control the heartbeat. As the 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 A-fib, the atria get abnormal signals. This causes them to contract in a fast and irregular way. They are out of sync with the ventricles. The atria 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 may contract too quickly and irregularly. They may not pump blood to the body and lungs as well as they should. This can weaken the heart muscle over time. It can lead to heart failure. Heart failure means the heart muscle can’t pump blood well.

What causes atrial fibrillation?

A-fib is more common in older adults. It can be caused by:

• 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 A-fib, health care providers don't know the cause.

What are the symptoms of atrial fibrillation?

A-fib 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 A-fib can include any of the 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 anticlotting medicines to help reduce the risk for blood clots and stroke.

• Left atrial appendage closure. Your health care provider may advise this procedure to prevent stroke. You may need it if you are at high risk for stroke but have problems taking blood-thinner (anticoagulant) medicines. This procedure is done through a catheter in the groin. A 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. It prevents clots moving from the heart to the brain and causing a stroke.

• Electrical cardioversion. Your provider uses special pads or paddles to send 1 or more brief electrical shocks to the heart. This treatment can help reset the heartbeat to normal.

• Ablation. Long, thin tubes (catheters) are threaded through a blood vessel to the heart. In the heart, the catheters send out hot or cold energy to the places that cause the abnormal signals. This destroys the problem tissue or cells. This treatment 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 help keep your heartbeat regular.

• Surgery. Your provider may use a method to create scar tissue in the parts of the heart causing the abnormal signals. The scar tissue disrupts the abnormal signals. This may stop A-fib from occurring. Most often, the left atrial appendage is closed off as well.

• Hybrid surgical-catheter ablation for A-fib. This treatment is used for people with A-fib that continues or is hard to treat. It combines surgery with a catheter ablation. First, 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. This is done to get to the backside and other areas of the heart. Energy is sent to the surface of the atria. This disrupts the abnormal electrical signals. Then a catheter is put into a vein in the groin. The catheter is guided into the heart. Using the catheter, radiofrequency ablation is done. This destroys any other tissue inside the heart that is causing the A-fib. It's also done to assess the success of the surgery. This hybrid treatment may work better to block the abnormal electrical signals. It may be a more lasting fix for persistent A-fib.

What are possible complications of atrial fibrillation?

Problems caused by A-fib can include:

• Blood clots.

• Stroke.

• Dementia.

• Heart failure.

When should I call my health care provider?

Contact your health care provider right away if you have any of these:

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

• New symptoms.