Atrial fibrillation (AFib) is a common type of abnormal heart rhythm characterized by rapid and irregular beating of the heart. The term “atrial fibrillation” describes a disturbance of the normal electrical impulses that coordinate contraction of heart muscle cells within the atria, which are upper chambers of the heart.
AFib symptoms include weakness, dizziness, feeling tired or short of breath. The following are the most common causes of aFib:

1. Thyroid disease
Thyroid disease, particularly hypothyroidism, is a known cause of atrial fibrillation. In many cases, this disease occurs due to autoimmune disorders that affect the function of the thyroid gland. This results in producing abnormal antibodies that lead to damage and reduced activity of the thyroid gland. As a result, the production of thyroid hormone is reduced, leading to atrial fibrillation.

2. Heart attack
The cerebrovascular disease that damages blood vessels over a period of time can also lead to atrial fibrillation. A blockage in the blood vessels supplying oxygen and nutrient-rich blood to the heart results in damage or death of cardiovascular cells. This leads to the formation of scar tissues that cannot conduct the electrical impulses required for the normal contraction of heart muscles. Scar tissues cannot contract and dilate, which leads to irregular and rapid beating of the heart resulting in atrial fibrillation.

3. Viral infections
Infections caused by viruses, such as the Epstein-Barr virus, cytomegalovirus, and influenza can also lead to atrial fibrillation. These viruses affect the function of heart muscle cells, resulting in damage or death of these cells. When heart muscle cells are damaged or die, it often leads to abnormal activity of electrical impulses, thus causing atrial fibrillation. This also may lead to other heart diseases such as dilated cardiomyopathy, coronary artery disease and myocarditis.

4. Sleep apnea
This is a medical condition in which breathing stops frequently during sleep. Patients with sleep apnea may have one or more pauses in their breathing, take rapid shallow breaths, or make snorting or choking sounds while sleeping. Sleep apnea can be caused by airway obstruction due to enlarged tonsils and adenoids, obesity, smoking, alcohol use or other medical conditions, and is one of the major causes of atrial fibrillation.

5. Uncontrolled high blood pressure
Obstruction of blood vessels by high blood pressure over the long term can also cause atrial fibrillation. This is because obstruction of blood flow due to excessive buildup of plaque in the arteries damages or kills cells present in the heart muscle, leading to the formation of scar tissues. These abnormal cells are unable to conduct electrical impulses, causing irregular and rapid beating of the heart, hence the presence of atrial fibrillation.

6. Certain lung diseases
Lung diseases such as chronic obstructive pulmonary disease (COPD) and interstitial lung disease can also lead to atrial fibrillation. These lung diseases damage the cells in the lungs, which are responsible for the proper breathing process. This results in irregularly fast or slow heartbeat resulting in atrial fibrillation.

7. Congenital heart defects or heart valve issues
Heart diseases at birth, such as congenital heart defects and issues with the heart valves, can also lead to atrial fibrillation. In the case of congenital heart defect, there is the improper formation of the chambers resulting in the irregular beating of the heart, which causes atrial fibrillation. In case of issues with heart valves, blood flows back and forth between the heart’s chambers due to inadequate closing of valves, resulting in atrial fibrillation.