Atrial fibrillation

Definition

Atrial fibrillation (AFib) is an uneven and fast heartbeat the upper part of the heart. AFib can decrease the amount of blood that is pumped out to the body. AFib may be:

• Occasional (paroxysmal)—AFib starts and stops over short periods usually less than 48 hours
• Persistent—constant and lasts more than 7 days
• Longstanding persistent—continues for more than a year
• Permanent

Afib can raise the risk of a heart attack, heart failure, or stroke. Treatment can help manage the condition.

Atrial Fibrillation

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Causes

The beating of the heart is started and controlled by electrical signals. These signals start from an area of the heart called the SA node. The signals then move through the heart in an organized way. Problems with the SA node or other areas of the heart can disrupt how the heart contracts. Irregular signals may also start in other areas of the heart.

Afib may be caused by one or more of the following:

• A problem with how the heart developed
• Damage to the heart
• Metabolic disorders—how the body processes food
• Endocrine disorders—abnormal amounts of hormone in the body
• Certain medicine or other medical treatment

Sometimes the exact cause is not known.

Risk Factors

AFib is more common in men and people over 55 years old.

AFib may also be more likely in those with:

• Family history of AFib
• High blood pressure
• Obesity
• Injury or disease of the heart such as:
  • Coronary artery disease
  • Heart failure
  • Heart attack
  • Endocarditis
  • Cardiomyopathy
  • Congenital heart disease or heart valve disease
• Lung diseases, such as emphysema , asthma , blood clots in the lungs
• Chronic endocrine disorders such as overactive thyroid or diabetes
• Long term prescription medicines such as opioids for pain relief
• Procedures that use general anesthesia

Certain habits can increase the risk of AFib, such as:

• Smoking
• Excessive alcohol use
• Excessive use of stimulants like caffeine
• Physical and/or emotional stress

Symptoms

AFib may not cause any symptoms. Symptoms that do occur may range from mild to severe.

Fast beating in the upper part of the heart may cause:

• An uneven or fast pulse or heart beat
• Racing feeling in the chest
• A pounding feeling in the chest

AFib that is decreasing the amount of blood pumped out to the body may cause:

• Lightheadedness, which can lead to fainting
• Sweating
• Pain or pressure in the chest
• Shortness of breath
• Tiredness or weakness
• Hard time exercising

Diagnosis

The doctor will ask about symptoms and past health. A physical exam will be done. The doctor may suspect a problem after listening to the heart or hearing about symptoms. Tests to confirm the diagnosis may include:

• ECG —shows the electrical patterns of the heart.
• Holter monitor —ECG that is worn over a 24 to 48 hours period during a normal day. It can help show problems that do not happen all the time.
• Stress testing—ECG during exercise to see changes that only happen with physical activity.

Treatment

For some people, AFib will go away without treatment. For others, goals of treatment may include:

• Stopping AFib (when possible).
• Slowing the fibrillation down; especially if there are symptoms.
• Decreasing the risk of other problems such as blood clots and stroke.

The exact plan will depend on the cause of the AFib. If a cause is found, that may need to be managed first. For example, stopping or changing medicine may stop the AFib.

Heart Rhythm Control

Steps that may help slow or stop AFib include:

• Medicine—to slow the heart rate or keep the heart in a regular rhythm
• Cardioversion—uses an electrical current or drugs to get a normal heart rhythm
• Surgical procedures—to redirect or slow the electrical signals of the heart
  • Ablation—an area of the heart may be damaged or scarred to stop stray electrical signals
  • Maze procedure and mini-maze procedure —a pattern of scar tissue is created to block fast or uneven electrical signals

Clot and Stroke Prevention

AFib allows blood to pool in the upper part of the heart. Blood clots can form in this pool, travel out of the heart, and cause a stroke. Medicine will help to stop these clots from forming. Some medicine can also increase the risk of severe bleeding. Care team will track changes in the blood to keep a balance between preventing blood clots and bleeding risks.

A procedure called left atrial appendage closure (LAAC) may be considered if medicine is not an option. This procedure seals off a small area of the upper heart where clots tend to form.

Reducing Triggers

Certain habits can trigger an episode of AFib or make it worse. To decrease the risk of making the AFib worse:

• Stop smoking
• Reduce or eliminate caffeine
• Reduce stress
• Eliminate or reduce alcohol intake

Prevention

It is not always possible to prevent AFib. Taking steps to have a healthy heart may reduce the risk of some AFib.

References

• Atrial fibrillation. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/atrial-fibrillation.
• Atrial fibrillation. CardioSmart website. Available at:https://www.cardiosmart.org/topics/atrial-fibrillation.
• Electrical cardioversion. Cleveland Clinic website. Available at: https://my.clevelandclinic.org/health/articles/electrical-cardioversion.
• Explore atrial fibrillation. National Heart,Lung, and Blood Institute website. Available at: https://www.nhlbi.nih.gov/health/atrial-fibrillation.
• Left atrial appendage and closure. Cleveland Clinic website. Available at: https://my.clevelandclinic.org/health/articles/left-atrial-appendage-closure.
• 4/5/2018 DynaMed Plus Systematic Literature Surveillance https://www.dynamed.com/condition/atrial-fibrillation : Asad Z, Abbas M, et al. Obesity is associated with incident atrial fibrillation independent of gender: a meta-analysis. J Cardiovasc Electrophysiol. 2018 Feb.