Atrial fibrillation

June 21, 2017

Atrial fibrillation (AF) is the most common type of arrhythmia and a major cause of stroke. As I explained in my previous story an arrhythmia is a problem with the rate or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm.

What is atrial fibrillation?
In normal healthy heart each electrical signal begins in a group of cells called the sinus node or sinoatrial (SA) node. The SA node is located in the right atrium and it sends an electrical signal to begin a new heartbeat which travels through the right and left atria. It causes the atria to contract and pump blood into the ventricles.

In AF, the heart's electrical signals don't begin in the SA node. Instead, they begin in another part of the atria or in the nearby pulmonary veins. The signals don't travel normally. They may spread throughout the atria in a rapid, disorganised way. This can make the atria to quiver or twitch which is known as fibrillation andis felt as an irregular and sometimes fast heartbeat, or pulse.

Types of Atrial Fibrillation
Paroxysmal Atrial Fibrillation
In paroxysmal atrial fibrillation, the faulty electrical signals and rapid heart rate begin suddenly and then stop on their own. Symptoms can be mild or severe. They stop within about a week, but usually in less than 24 hours.

Persistent Atrial Fibrillation
Persistent AF is a condition in which the abnormal heart rhythm continues for more than a week. It may stop on its own, or it can be stopped with treatment.

Permanent Atrial Fibrillation
Permanent AF is a condition in which a normal heart rhythm can't be restored with treatment. Both paroxysmal and persistent AF may become more frequent and, over time, result in permanent AF.

Risk Factors or causes of atrial fibrillation
AF is more common in people who have high blood pressure, coronary artery disease, heart failure, rheumatic heart disease, structural heart defect (mitral valve prolapse), and congenital heart defects.

Other conditions that increase risk for AF include hyperthyroidism, obesity, diabetes, and lung disease.
According to the literature there are other risks factors might also contribute in causing AF for example, drinking large amounts of alcohol, caffeine or psychological stress also may trigger AF in some people.

Symptoms of atrial fibrillation
Symptoms can include palpitations (feelings that heart is skipping a beat, fluttering, or beating too hard or fast), shortness of breath, weakness or problems exercising, chest pain, dizziness or fainting, fatigue (tiredness) and confusion
However, some people only have mild symptoms, while other people have no symptoms at all.

Complications of atrial fibrillation
The most major complications of AF are stroke and heart failure
During AF, the heart's upper chambers, the atria, don't pump all of their blood to the ventricles. Some blood pools in the atria. When this happens, a blood clot (also called a thrombus) can form.

If the clot breaks off and travels to an artery in the brain it can block blood flow through the artery and the lack of blood flow to the portion of the brain fed by the artery causes a stroke.

Accordingly, researches and evidences had been shown that blood-thinning medicines are an important part of treatment for people who have AF in order to reduce the risk of having stroke.

Diagnosis and treatment of atrial fibrillation
Atrial fibrillation is diagnosed based on medical and family histories, a physical exam, and the results from tests and procedures.
Sometimes AF doesn't cause signs or symptoms. Thus, it may be found during a physical exam or ECG (electrocardiogram) test done for another purpose.

If AF detected then special test are needed for confirmation of diagnosis and start of special treatment which includes heart rate control, rhythm control and prevention of stroke.