Approximately 300 000 Canadians (1%) experience atrial fibrillation (AFib), making it the most common heart rhythm disorder.
During atrial fibrillation, the upper heart chambers (called the 'atria') beat up to 400 times a minute (five times faster than normal). At this rate, the upper chambers (atria) do not pump properly and are essentially quivering (“fibrillating”). The upper and lower heart chambers are electrically isolated from one another, but a specialized region in the middle of the heart called the AV node receives signals from the upper chambers and slowly transmits them down to the lower chambers. During atrial fibrillation, the AV node prevents most signals from reaching the lower chambers, but patients will typically experience a rapid, irregular pulse due to the random transmission of signals from top to bottom. The lower heart chambers (called 'ventricles") are responsible for the pulse and perceived heart rate.
AFib is more common with advancing age and is also commonly associated with other heart conditions (including coronary artery disease, hypertension, heart failure, valvular heart disease and congenital heart disease). Patients with diabetes mellitus and those who engage in extreme endurance sports are also at higher risk of developing this condition.
Consequences of AFib
Although it isn’t generally considered an immediate threat to life, AFib can lead to palpitations, chest pain, malaise, fatigue and heart failure. The chances of having a stroke are also five times higher in individuals who have AFib.
Stroke ("Brain attack")
When the upper chambers are in fibrillation ('quivering'), blood does not flow normally through the heart and can form clots. These clots can travel to the brain, resulting in death of brain tissue due to a lack of blood flow to one area (stroke). Less commonly, a blood clot can travel to a limb and cause an extremely painful condition called an ischemic limb due to thromboembolism. It is estimated that at least one in five strokes are caused by Afib.
Palpitations, Fatigue, Chest discomfort
Some people with AFib are very bothered by their irregular heart beat and some feel very tired and cannot exercise normally. On the other hand, one third of people with AFib do not feel any different than usual.
People with AFib are at higher risk of developing heart failure. This is especially common when people do not feel their AFib and go untreated for many months. Atrial fibrillation which causes a rapid pulse which is undetected for months can cause a severe weakness of the heart and heart failure.
There is no cure at the present time for atrial fibrillation, but there are many effective treatments that can control the adverse consequences of AFib.
Anticoagulants (blood thinners)
If the risk of stroke is very high (more than 4-5% per year), then powerful blood thinners may be needed to prevent stroke. These reduce the risk of stroke by about 70-80% and are much more effective than aspirin, which reduces the risk from AFib by only about 20%.
Most patients with atrial fibrillation will need medications to slow down their pulse (to prevent heart failure) or to prevent AFib altogether (although no drug exists that can completely prevent all episodes of AFib).
Some patients with AFib do not respond to medications and require more aggressive treatments. These may include pacemaker insertion or an AF ablation procedure (which consists of controlled burns in the left upper chamber of the heart to prevent signals in the pulmonary veins from triggering AFib. These burns are performed under light sedation via catheters inserted in the vein of the right thigh.
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Disclaimer: The brief patient information supplied here and the outside links provided are not intended to replace the advice of your physician and are only meant to help guide patients to formulate questions during their physician appointments. Each patient's situation is unique and a large number of factors are considered when arriving at a management plan for your specific condition.
Atrial Fibrillation and Atrial flutter