What are the Most Common Causes of Atrial Fibrillation?

The most common causes leading to atrial fibrillation include heart valve disease, heart failure, and others.

Atrial fibrillation (AF, AFib) is an abnormal heart rhythm characterized by an irregular and fast heartbeat. The upper chambers of the heart (atria) beat chaotically.  This can cause pooling and clotting of blood in the atria, instead of it emptying into the lower chamber (ventricles). AF can lead to stroke, heart failure, blood clots, and heart-related complications.

In the United States, approximately 5 million people are affected by atrial fibrillation. Atrial fibrillation is classified into three types:

• Paroxysmal atrial fibrillation: AF attacks that last for less than 24 hours
• Persistent atrial fibrillation: AF attacks that last for more than seven days and require treatment
• Long-standing persistent atrial fibrillation: AF that has continued for more than a year

The most common causes leading to atrial fibrillation include:

• Heart valve disease
• Heart muscle disease
• Heart disease due to high blood pressure
• Heart defects at birth
• Heart failure
• Inflammation of the outer lining of the heart (pericardium)
• Previous heart surgery
• Drug and alcohol abuse
• Thyroid disorders
• Uncontrolled diabetes
• Chronic lung disorder
• Infections
• Genetics
• Snoring during sleep
• Medications such as theophylline, digitalis, and adenosine
• Age over 60 years

Frequently, persons with AFib have no symptoms. When Symptoms do occur, the signs of AFib include:

• Fast or fluttering heartbeat
• Shortness of breath
• Fatigue
• Weakness
• Chest pain or discomfort
• Dizziness
• Bulging eyes
• Wheezing
• Cold feet or hands

The tests commonly used in evaluating a patient with atrial fibrillation are:

• Electrocardiogram (ECG)
• Laboratory tests such as complete blood cell count (CBC), blood urea nitrogen (BUN), creatinine kinase (CK), b-type natriuretic peptide, d-dimer level, and digoxin level
• Echocardiography
• Computed tomography (CT) scanning and magnetic resonance imaging (MRI)
• Holter monitoring
• Electrophysiology studies
• Exercise stress test

Atrial fibrillation is a serious condition that, if untreated, doubles the risks of heart-related deaths and stroke. The Framingham Heart Study reported that AFib increases the risk of death by 1.5-fold in men and 1.9-fold in women.  So, it is important to control atrial fibrillation.

The four major goals of atrial fibrillation are

• Regaining a normal heart rhythm,
• Controlling heart rate,
• Preventing blood clots, and
• Mitigating the risk of stroke.

The various treatment options include drug therapy, surgery, and lifestyle changes.

Drug Therapy

Medications commonly used to treat atrial fibrillation are:

• Antiarrhythmic drugs: Medications such as procainamide and amiodarone help to treat irregular heartbeats.
• Rate control medications: Medications such as digoxin, metoprolol, and verapamil control the heart rate.
• Anticoagulant medications: Medications such as warfarin prevent the formation of clots.

When drug therapy fails, procedures to treat atrial fibrillation include:

• Electrical cardioversion: Restoring normal heart rhythm by using electrical shock with the patient under anesthesia.
• Pulmonary vein ablation: Applying radiofrequency energy or freezing to excitable electrical tissue around the connections of the pulmonary vein near the atrium.
• Ablation of the AV node: A catheter is directed to the heart through the groin. A small area of tissue around the junction connecting the upper (atria) and lower (ventricles) chambers of the heart are destroyed with radiofrequency energy.
• Patients with a slow heart rate may have a pacemaker installed with a pulse generator and wires that transmit electrical impulses to the heart.
• Left atrial appendage closure: A small, ear-shaped sac present in the muscle wall of the atrium that is closed to prevent stroke.

Surgery

Some patients, who have had failed drug therapy and catheter ablation or with blood clots in the left atrium, recent stroke and an enlarged left atrium may be suitable for surgical treatment:

• Maze procedure: This procedure involves a series of cuts made in the upper chambers of the heart to block any abnormal electrical impulse.
• Excision of the left atrial appendage: Surgical removal of the left atrial appendage.

Lifestyle changes

Lifestyle changes for AF include:

• Quit tobacco smoking
• Limit alcohol and caffeine intake
• Avoid activities that aggravate the symptoms
• Control blood pressure
• Shed extra pounds
• Monitor and control blood sugar levels
• Treat snoring problems
• Limit the use of cold and cough medicine