About Atrial Fibrillation
Atrial fibrillation, or AF, is a common cardiac rhythm condition (arrhythmia) that is seen increasingly with age (especially over age 60). The normal electrical trigger for the heart beat in the top chambers (atria) of the heart becomes disrupted by rapid, erratic electrical signals that result in a quivering motion of the top chambers (so called "atrial fibrillation") rather than the regular pumping action.
The erratic electrical signals are transmitted to the lower chambers of the heart and cause a reduced efficiency of the overall heart pumping function. Most people develop symptoms from the arrhythmia, which affects their quality of life. It is well known that small numbers of people with AF don't seem to have any awareness of the arrhythmia but it remains unclear why symptoms can vary so much from person to person.
- Palpitations – a fluttering or thumping feeling in the chest or throat
- Shortness of breath
- Lightheadedness or fainting
- Chest pain or heaviness
- Feelings of irritability, anxiety or generally unwell
- Reduced exercise capacity or endurance
The majority of AF is caused by other underlying heart problems or other conditions such as high blood pressure (hypertension) and sleep apnoea.
The thin walled top chambers of the heart become enlarged or damaged by these conditions leading to the abnormal erratic electrical signals. In some cases no other heart problem is present and AF could be caused by thyroid problems, over activity of vagal nerve inputs to the heart or a genetic abnormality. It is important to treat or control any underlying condition, which could be causing AF for successful treatment.
The inefficiency of the heart pumping action caused by AF may lead to weakness of the heart muscle and heart failure, or a worsening of any existing heart problems. A small number of people may go through life with AF and have little or no health problems from the condition.
One of the greatest health risks from AF is an increased risk of stroke. People with a current or past diagnosis of AF have around 5 times the risk of having a stroke as a person without AF. AF leads to an increased risk of a blood clot forming in the top chambers of the heart (in particular left atrial appendage – link to stroke prevention treatments page), which, if it dislodges and travels to the brain, results in a stroke. Being in normal rhythm rather than AF does not necessarily reduce the risk of blood clots and stroke.
More information on Stroke Prevention Treatments in AF.
Whether AF responds to treatments to restore normal rhythm may depend on the type of AF. The type of AF is characterised by the duration of the arrhythmia and individual episodes.
Paroxysmal AF refers to a pattern of intermittent episodes of AF, which start and stop spontaneously without treatment. Episodes are short but may last hours or days.
Persistent AF refers to a pattern of continuous AF, which does not return to normal rhythm on its own.
Longstanding Persistent AF refers to a pattern of continuous AF, which has been present for 12 months or longer.
The presence of continuous AF is known to lead to progressive damage and scarring of the top chambers of the heart, which may significantly reduce the efficacy of different treatments to restore normal rhythm.
Permanent AF refers to continuous AF that has either been accepted indefinitely or cannot be corrected by treatments.