What Is Afib?

Atrial fibrillation (afib) is an arrhythmia, or an irregular heart rhythm.

With afib, the electrical signals that coordinate the muscles of the upper chambers (atria) of the heart become rapid and disorganized. All of these electrical signals cause the heart ventricles to beat irregularly, or fibrillate, instead of contract in an organized way.

Atrial Flutter

Afib alone is not life threatening, but it can be extremely bothersome and sometimes dangerous. It can last for a short time or occur all the time. Sometimes afib makes your pulse fast and irregular or slow and irregular.

What makes a normal heart beat? The heart is a large muscle with four chambers. There are two top chambers (left and right) called the atria and two bottom chambers (left and right) called the ventricles. These chambers fill with blood from the body and then squeeze to circulate or deliver blood to other areas of the body, such as the lungs so that oxygen can be added, or oxygen filled blood to the rest of the body tissues. The heart muscle contracts after it is stimulated (or told to) by an electrical impulse. There is an area of special tissue in the right atrium called the SA node, which starts an electrical impulse that will eventually travel down the electrical tracts (AV node and bundle branches ) within the heart and create a heartbeat. First the atria contract and squeeze blood into the ventricles, then the ventricles contract (squeeze). That is what makes the "lub, dup" sound that we hear when we listen to someone's heart.

Afib Causes

The exact cause of afib isn't always clear.

Patients, most often younger than 65, who develop afib may have no changes in their heart structure or other particular cause for their afib. This has been called Lone afib.

In other patients, afib occurs with other medical conditions that can cause changes in the electrical properties or structure of the heart.

Risk

Risk factors for afib include:

• High blood pressure
• Coronary artery disease (a condition in which the normal blood flow to the heart is changed because of blockages in arteries)
• Heart failure
• Heart valve disease
• Lung disease
• Thyroid problems
• Pericarditis (inflammation around the heart)
• Excessive alcohol intake, particularly binges
• Recent heart surgery
• Structural heart defects present from birth
• Genetic inheritance

Symptoms of Atrial Fibrillation

Atrial fibrillation episodes can last anywhere from minutes to hours to days. People with afib may have several symptoms or no symptoms.

Some people with afib are bothered by the fast irregular beats, or just by the feeling that their heart is beating irregularly. Sometimes after an afib episode ends, it takes the top chamber of the heart a short time to start working properly again, and there may be a short pause in heartbeats.

Because the way the heart is beating and pumping changes during an afib episode, you may feel some other symptoms – especially when you are active. These symptoms include:

• Palpitations (skipped or extra heartbeats)
  
• Shortness of breath, especially when climbing stairs or walking long distances
  
• Feeling fatigued and tired, especially during an afib episode
  
• Chest discomfort or pain
  
• Dizziness or lightheadedness
  
• Fainting