A heart in atrial fibrillation doesn’t beat efficiently. It may not be able to pump enough blood out to your body with each heartbeat. Some people with atrial fibrillation have no symptoms and are unaware of their condition until it’s discovered during a physical examination. Those who do have atrial fibrillation symptoms may experience:
- Palpitations, which are sensations of a racing, uncomfortable, irregular heartbeat or a flopping in your chest
- Decreased blood pressure
- Light headedness
- Shortness of breath
- Chest pain
If you have any symptoms of atrial fibrillation, make an appointment with your doctor. Your doctor should be able to tell you if your symptoms are caused by atrial fibrillation or another heart arrhythmia.
If you have chest pain, seek emergency medical assistance immediately. Chest pain could signal that you’re having a heart attack.
Your heart consists of four chambers — two upper chambers (atria) and two lower chambers (ventricles). Within the upper right chamber of your heart (right atrium) is a group of cells called the sinus node. This is your heart’s natural pacemaker. The sinus node produces the impulse that normally starts each heartbeat.
Normally, the impulse travels first through the atria and then through a connecting pathway between the upper and lower chambers of your heart called the atrioventricular (AV) node. As the signal passes through the atria, they contract, pumping blood from your atria into the ventricles below. As the signal passes through the AV node to the ventricles, the ventricles contract, pumping blood out to your body.
In atrial fibrillation, the upper chambers of your heart (atria) experience chaotic electrical signals. As a result, they quiver. The AV node — the electrical connection between the atria and the ventricles — is overloaded with impulses trying to get through to the ventricles. The ventricles also beat rapidly, but not as rapidly as the atria. The reason is that the AV node is like a highway on-ramp — only so many vehicles can get on at one time.
The result is a fast and irregular heart rhythm. The heart rate in atrial fibrillation may range from 100 to 175 beats a minute. The normal range for a heart rate is 60 to 100 beats a minute.
- High blood pressure
- Heart attacks
- Abnormal heart valves
- Heart defects you’re born with (congenital)
- An overactive thyroid gland or other metabolic imbalance
- Exposure to stimulants, such as medications, caffeine or tobacco, or to alcohol
- Sick sinus syndrome — functioning of the heart’s natural pacemaker
- Emphysema or other lung diseases
- Previous heart surgery
- Viral infections
- Stress due to pneumonia, surgery or other illnesses
- Sleep apnoea
However, some people who have atrial fibrillation don’t have any heart defects or damage, a condition called lone atrial fibrillation. In lone atrial fibrillation, the cause is often unclear, and serious complications are rare.
Atrial flutter is similar to atrial fibrillation, but the rhythm in your atria is more organized and less chaotic than the abnormal patterns common with atrial fibrillation. Sometimes you may have atrial flutter that develops into atrial fibrillation and vice versa. The symptoms, causes and risk factors of atrial flutter are similar to those of atrial fibrillation. For example, strokes are also a concern in someone with atrial flutter. As with atrial fibrillation, atrial flutter is usually not life-threatening when it’s properly treated
Risk factors for atrial fibrillation include:
Age: The older you are, the greater your risk of developing atrial fibrillation.
Heart disease: Anyone with heart disease, including valve problems and a history of heart attack and heart surgery, has an increased risk of atrial fibrillation.
High blood pressure: Having high blood pressure, especially if it’s not well controlled with lifestyle changes or medications can increase your risk of atrial fibrillation.
Other chronic conditions: People with thyroid problems, sleep apnoea and other medical problems have an increased risk of atrial fibrillation.
Drinking alcohol: For some people, drinking alcohol can trigger an episode of atrial fibrillation. Binge drinking — having five drinks in two hours for men, or four drinks for women — may put you at higher risk.
Family history: An increased risk of atrial fibrillation runs in some families.
Sometimes atrial fibrillation can lead to the following complications:
Stroke: In atrial fibrillation, the chaotic rhythm may cause blood to pool in your heart’s upper chambers (atria) and form clots. If a blood clot forms, it could dislodge from your heart and travel to your brain. There it might block blood flow, causing a stroke.
The risk of stroke in atrial fibrillation depends on your age (you have a higher risk as you age) and on whether you have high blood pressure, diabetes, or a history of heart failure or previous stroke, and other factors. Certain medications, such as blood thinners, can greatly lower your risk of stroke or damage to other organs caused by blood clots.
Heart failure: Atrial fibrillation, especially if not controlled, may weaken the heart and lead to heart failure — a condition in which your heart can’t circulate enough blood to meet your body’s needs.
Despite any ongoing controversy regarding the role of OSA in the development of cardiovascular disease, it seems that AF is a well-established consequence of sleep-disordered breathing. The physiologic derangements in cardiopulmonary hemodynamics, sympathetic tone, and physical structure of the left atrium that result from OSA seem well suited as causative factors for AF. In addition, numerous studies have found a higher-than-expected prevalence of AF among patients with OSA and more OSA among patients with AF. The presence of untreated OSA seems to decrease the efficacy of chemical cardioversion, electrical cardioversion, and catheter ablation; similarly, recurrence of AF is significantly more common among patients with untreated OSA, whereas CPAP therapy seems to mitigate this risk.
Given the prevalence of OSA among patients with AF and its impact on outcomes, clinicians should assess individuals with AF for sleep-disordered breathing. If OSA is clinically suspected these patients should be referred for polysomnography.