What Is Atrial Fibrillation?
Atrial fibrillation (A-fib) is an abnormal heart rhythm (arrhythmia) characterized by a rapid rate and irregular rhythm that feels like the heart is quivering. It can lead to chest discomfort, shortness of breath, lightheadedness, and the formation of blood clots, which can cause a stroke. A-fib is common, affecting five to 10 percent of adults older than 65 .
Heart damage from high blood pressure, congenital heart defects, viral infections, and sleep apnea can cause atrial fibrillation. Other risk factors include increasing age, obesity, family history, and drinking alcohol.
Treatment involves cardioversion with mild electrical shock or medication to return the heart to normal rhythm. Blood thinners and medication to maintain heart rhythm will be prescribed. Procedures may be needed in some cases.
Call 911 immediately for an ambulance. The symptoms of atrial fibrillation can be hard to distinguish from a heart attack, so better be safe.
How common is Atrial Fibrillation?
Atrial Fibrillation is also known as
Atrial Fibrillation Symptoms
A-fib and the causes are diagnosed through electrocardiogram, echocardiogram, blood test, stress test, and chest X-ray. Untreated atrial fibrillation may lead to heart failure and other complications. A-fib can be described by a few main symptoms as well as further classification of symptom patterns.
Main symptoms of A-fib include the following.
- Fast heart rate (tachycardia): A heart rate greater than 100 beats per minute (bpm) is typically considered elevated. In A-fib, the heart rate may greatly exceed 100 bpm.
- Palpitations: You may become uncomfortably aware of your heart's beating and experience pounding, fluttering, or feel like your heart is skipping beats.
- Lightheadedness, shortness of breath (dyspnea) and fatigue: Due to inadequate pumping of blood and poor oxygen delivery to the tissues, you may experience these heart failure symptoms similar to exhaustion.
Classification of symptom patterns
Four typical patterns of A-fib have been defined . These include:
- Paroxysmal: Episodes of A-fib will occasionally come and go, usually lasting a few hours to two days, and then remitting, even without treatment.
- Persistent: Untreated episodes persist for greater than one week.
- Long-standing persistent: This is continuous A-fib for longer than one year.
- Permanent: This is A-fib that is persistent. You and your physician may decide to forgo a plan for rhythm control.
Complications of A-fib
Complications that may occur due to A-fib include the following.
- Stroke: A-fib increases the risk of stroke more than fourfold, but up to 80 percent of strokes can be prevented in people who have A-fib .When the atria are not pumping normally, blood clots can form. When these clots leave the atria, they can travel into the arteries and block blood flow to the brain, resulting in a stroke.
- Heart failure: Persistent A-fib can weaken the heart muscle, resulting in heart failure, whereby the heart no longer adequately pumps blood throughout the body.
Atrial Fibrillation Causes
Atrial fibrillation occurs when electrical signals in the two upper chambers of the heart do not coordinate with signals in the two lower chambers. This can be due to other medical conditions or certain triggers.
Normal and abnormal heart function
The heart has two upper chambers (atria) and two lower chambers (ventricles). Typically, the muscular walls of the chambers tighten to pump out blood and then relax to enable refilling. The coordinated contraction of the heart muscles is controlled by electrical signals. Typically, the sinus node, located in the right atrium, acts as the pacemaker for the heart.
During A-fib, abnormal electrical signals fire, either in the atria or the veins adjacent to the atria, overriding the natural pacemaker and resulting in a rapid and irregular heartbeat. The irregular heartbeat causes the upper chambers to beat chaotically and without proper coordination with the lower chambers. Because the chambers may not relax long enough to allow filling, a reduced cardiac output can occur, leading to lightheadedness and other symptoms.
The following conditions are associated with the development of A-fib .
Heart disease: This includes valve defects (especially rheumatic mitral valve failure), heart failure, atherosclerosis, coronary artery disease, congenital heart disease (such as atrial septal defects), cardiomyopathy, pericarditis, and history of heart attacks or heart surgeries.
Hyperthyroidism: This is mainly associated with Grave's Disease.
- Lung disease: This includes asthma, COPD, lung cancer, pneumonia, obstructive sleep apnea, and pulmonary embolism.
- Kidney disease
- Idiopathic A-fib: This is when A-fib occurs in otherwise healthy people younger than age 60 with none of the conditions listed above.
Triggers of A-fib episodes
The following are known triggers of A-fib episodes and should be limited or avoided altogether.
- Binge drinking: Alcohol in excess ("holiday heart")
- Excessive caffeine intake: Tea, coffee, or energy drinks
- Stimulant drugs: Cocaine or methamphetamines
- Smoking cigarettes
Treatment Options and Prevention for Atrial Fibrillation
If you have uncontrolled conditions associated with A-fib, such as hyperthyroidism or hypertension, treatment of these conditions may facilitate remission of the A-fib. Further medications will likely be needed to address blood clots, heart rate, and rhythm. If these are ineffective, your medical provider may recommend procedures.
During prolonged A-fib, blood clots can form in the atria. When these clots become dislodged, they can travel to the brain and cause a stroke. To prevent strokes in A-fib, blood thinning medications such as warfarin or rivaroxaban often are given to prevent the formation of clots. Anticoagulation raises your risk of bleeding, so your physician will discuss the risk and benefits of starting the medication. Anticoagulation is particularly beneficial in people who have a history of stroke or clots, heart failure, hypertension, diabetes, or heart disease.
Heart rate and rhythm control
Your physician may recommend medications to control your heart rate or rhythm.
- Rhythm control: A variety of medications can affect heart rhythm, including beta-blockers, such as sotalol, medications that affect sodium channels in the heart, such as flecainide, and a medication that affects potassium channels, amiodarone. The choice of antiarrhythmic medication is a complex decision based on your own heart rhythm and medical history .
- Rate control: Beta-blockers, such as atenolol and bisoprolol, and calcium channel blockers, such as verapamil and diltiazem, can prevent excessive heart rates.
If the methods above do not provide relief, your physician may address other issues associated with A-fib with the following procedures.
- Cardioversion: If your blood pressure becomes unstable due to A-fib or the arrhythmia does not respond to medications, physicians may recommend applying a controlled electric shock to the heart to restore normal heart rhythm.
- Catheter ablation: Specialized cardiologists (electrophysiologists) can run a thin, soft wire from the arteries into the heart to carefully destroy the cells that are causing the irregular rhythm. Following the procedure, an artificial pacemaker is implanted to ensure regular heart rate and rhythm.
Lifestyle changes can help reduce your risk of heart disease and A-fib . These include:
- Exercising regularly
- Eating a healthy diet
- Not smoking tobacco
- Limiting alcohol intake
When to Seek Further Consultation for Atrial Fibrillation
If you have chest pain, particularly if accompanied by shortness of breath, seek emergency medical attention. Chest pain can be a symptom of serious cardiac problems.
If you have A-fib and develop symptoms of stroke
Seek emergency medical attention for confusion, facial droop, slurred speech, blurry vision, weakness, numbness, or loss of balance. A-fib significantly raises the risk of stroke. Outcomes from strokes are best when symptoms are detected early.
If your heart rate is irregular and you feel dizzy or short of breath
Contact your physician if your heart rate is less than 60 bpm or greater than 100 bpm and you feel dizzy or short of breath. You can count your heart rate by holding your fingers over your carotid artery on the side of your neck, under your jaw. Some smartphones and watches also enable determination of your heart rate.
Questions Your Doctor May Ask to Determine Atrial Fibrillation
To diagnose this condition, your doctor would likely ask about the following symptoms and risk factors.
- Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?
- Do you have a cough?
- Do you notice your heart beating hard, rapidly, or irregularly (also called palpitations)?
- Where is your chest pain exactly?
- Are you sick enough to consider going to the emergency room right now?
The above questions are also covered by our A.I. Health Assistant.
- Management of patients with atrial fibrillation (compilation of 2006 ACCF/AHA/ESC and 2011 ACCF/AHA/HRS recommendations): A report of the American College of Cardiology/American Heart Association Task Force on practice guidelines. Circulation. 2013;127(18):1916. UpToDate Link
- Division for heart disease and stroke prevention. Centers for Disease Control and Prevention. Updated August 22, 2017. CDC Link
- Chugh SS, Blackshear JL, Shen WK, Hammill SC, Gersh BJ. Epidemiology and natural history of atrial fibrillation: Clinical implications. J Am Coll Cardiol. 2001;37(2):371. UpToDate Link
- Abed HS, Wittert GA, Leong DP, et al. Effect of weight reduction and cardiometabolic risk factor management on symptom burden and severity in patients with atrial fibrillation: A randomized clinical trial. JAMA. 2013;310(9):2050-2060. UpToDate Link
- January CT, Wann LS, Alpert JS, et al. 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: Executive summary: A report of the American College of Cardiology/American Heart Association Task Force on practice guidelines and the Heart Rhythm Society. Circulation. 2014;130(23):2071. UpToDate Link
- What is the AFib-stroke connection? American Stroke Association. American Stroke Association Link
- Ionescu-Ittu R, Abrahamowicz M, Jackevicius CA, et al. Comparative effectiveness of rhythm control vs rate control drug treatment effect on mortality in patients with atrial fibrillation. Arch Intern Med. 2012;172(13):997. UpToDate Link