Atrial fibrillation is a type of arrhythmia, or irregular heartbeat, that occurs when the heart's two upper chambers--the left and right atria--beat erratically and out of sync with its two lower chambers--the left and right ventricle. The symptoms of atrial fibrillation can range from occasional heart palpitations to chronic lightheadedness, fatigue and chest discomfort. Typically developing as a result of certain health problems that interfere with blood flow or the electrical signals that pace the heart, atrial fibrillation is a potentially serious medical condition that requires prompt treatment.
Structural Heart Problems
According to MayoClinic.com, defects or damage to structures within the heart are among the most common causes of atrial fibrillation. For example, congenital heart defects--those present at birth--or problems with one or more of the heart's valves can interfere with the pace and volume of blood flow into and out of the heart's chambers, in turn causing irregular functioning of the atria. Another structural defect that may lead to atrial fibrillation is sick sinus syndrome--a condition in which the heart's sinus node, which normally serves as an automatic pacemaker, fails to send out regular electrical impulses. According to MayoClinic.com, scarring from disease or previous heart surgery can damage the sinus node and cause atrial fibrillation.
Cardiomyopathy
Cardiomyopathy--a disease that causes the heart muscle to enlarge and become weak--can cause atrial fibrillation. According to Cleveland Clinic, as the heart grows in size, it is less able to pump blood. Simultaneously, heart tissue thickens and scars, making the heart rigid. Because the heart is stiff and not able to pump blood effectively, it fails to maintain a normal rhythm, leading to arrhythmias such as atrial fibrillation.
Pericarditis
Pericarditis is an inflammation of the pericardium, the fluid-filled covering that surrounds the heart. The condition may develop as a result of an infection, autoimmune disease, heart attack or heart surgery, according to Cleveland Clinic. As the pericardium swells, it can constrict the heart, preventing it from pumping normally. Restricting the heart's ability to expand can in turn disrupt its normal rhythm, leading to atrial fibrillation.
Stimulants, Toxins and Electrolyte Imbalances
Electrolyte imbalances--abnormally low or high levels of critical minerals such as calcium, potassium and sodium--can interfere with the electrical signals produced by the heart, causing atrial fibrillation. Metabolic disorders characterized by the over- or underproduction of certain hormones can also cause the heart's upper chambers to beat erratically. For example, hyperthyroidism--a condition in which the body produces too much thyroid hormone--is known to cause atrial fibrillation, according to MayoClinic.com.
Substances that act as stimulants can also cause an irregular atrial rhythm. Caffeine, tobacco and certain medications and illicit drugs may all cause the heart's upper chambers to fibrillate. Alcohol can damage the heart when consumed in excessive amounts. According to HealthCommunities.com, chronic drinking and binge drinking can cause atrial fibrillation.
Lung and Breathing Problems
According to Cleveland Clinic, chronic lung diseases--emphysema, for example--may cause atrial fibrillation by interfering with blood flow into and out of the heart. Pulmonary embolisms--blood clots in the lungs that form when clots dislodge from other parts of the body and travel to the airways--can also restrict blood flow and increase blood pressure in the lungs, in turn putting increased strain on the heart which can lead to an atrial arrhythmia.
Other conditions that affect breathing and may induce atrial fibrillation include pneumonia and sleep apnea--a disorder characterized by intermittent stopping and starting of breathing during sleep. According to MayoClinic.com, when breathing stops, the body can become deprived of oxygen. Low levels of oxygen in the bloodstream interfere with normal cardiovascular function and can cause atrial fibrillation.
