Atrial fibrillation or flutter

Causes

Normally, the four chambers of the heart contract (squeeze) in a very organized way.

The electrical impulse that signals your heart to contract begins in an area called the sinoatrial node (also called the sinus node or SA node). This helps the heart pump all the blood the body needs.

In atrial fibrillation, the electrical impulse of the heart is not regular.

• Parts of the heart cannot contract in a coordinated pattern.
• As a result, the heart cannot pump enough blood to meet the body's needs.

In atrial flutter, the ventricles may beat very rapidly, but in a regular pattern.

These problems can affect both men and women and become more common as you get older.

Common causes of atrial fibrillation include:

• Alcohol use (especially binge drinking) 
• Coronary artery disease
• Heart attack or heart bypass surgery
• Heart failure or an enlarged heart
• Heart valve disease (most often the mitral valve)
• Medications
• Overactive thyroid gland (hyperthyroidism)
• Pericarditis
• Sick sinus syndrome

Symptoms

You may not be aware that your heart is not beating in a normal pattern.

Symptoms may start or stop suddenly. This is because atrial fibrillation may stop or start on its own.

Symptoms may include:

• Pulse that feels rapid, racing, pounding, fluttering, irregular, or too slow
• Sensation of feeling the heart beat (palpitations)
• Confusion
• Dizziness, light-headedness
• Fainting
• Fatigue
• Loss of ability to exercise
• Shortness of breath

Exams and Tests

The health care provider may hear a fast heartbeat while listening to your heart with a stethoscope. Your pulse may feel fast, uneven, or both.

The normal heart rate is 60 - 100, but in atrial fibrillation/flutter the heart rate may be 100 - 175. Blood pressure may be normal or low.

An ECG -- a test that records the electrical activity of the heart -- may show atrial fibrillation or atrial flutter.

If your abnormal heart rhythm comes and goes, you may need to wear a special monitor that records the heart's rhythms to help diagnose atrial fibrillation.

• Event monitor
• Holter monitor (24-hour test)
• Implanted loop recorder

Tests to find heart disease may include:

• Echocardiogram (ultrasound imaging of the heart)
• Tests to examine the blood supply of the heart muscle
• Tests to study the heart's electrical system

Treatment

To help get the heart back into normal rhythm right away, two treatments may be used. These treatments are called cardioversion. They may involve electrical shocks or special drugs given through the veins. They may be done as an emergency, or planned ahead of time.

Daily medicines taken by mouth are used:

• To slow the irregular heartbeat. These medications may include beta-blockers, calcium channel blockers, and digoxin.
• To keep atrial fibrillation from coming back. These medications may work well in many people, but they can have serious side effects. Many patients go back to atrial fibrillation, even while taking these medications.

Blood thinners -- such as heparin, warfarin (Coumadin), apixaban, and dabigatran (Pradaxa) -- reduce the risk of a blood clot traveling in the body (such as a stroke). Because these drugs increase the chance of bleeding, not everyone can use them. Antiplatelet drugs such as aspirin or clopidogrel may also be prescribed. Your doctor will consider your age and other medical problems when deciding which drug is best.

A procedure called radiofrequency ablation can be used to destroy areas in your heart that may be causing your heart rhythm problems. You may need a heart pacemaker after this procedure.

All patients will need to learn how to manage their atrial fibrillation at home.

Outlook (Prognosis)

Treatment can often control this disorder. Many people with atrial fibrillation do very well.

However, atrial fibrillation tends to return and get worse. It may come back even with treatment.

Clots that break off and travel to the brain can cause a stroke.

When to Contact a Medical Professional

Call your health care provider if you have symptoms of atrial fibrillation or flutter.

Prevention

Follow your health care provider's recommendations for treating conditions that cause atrial fibrillation/flutter. Avoid binge drinking.

Alternative Names

Auricular fibrillation; A-fib

References

Dobrev D, Nattel S. New antiarrhythmic drugs for treatment of atrial fibrillation. Lancet. 2010;375:1212-1223.

Fuster V, Ryden LE, Cannom DS, Crijns HJ, Curtis AB, Ellenbogen KA, et al. 2011 ACCF/AHA/HRS focused updates incorporated into the ACC/AHA/ESC 2006 Guidelines for the management of patients with atrial fibrillation: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines developed in partnership with the European Society of Cardiology and in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. J Am Coll Cardiol. 2011;57:e101-198.

Morady F, Zipes DP. Atrial fibrillation: clinical featuers, mechanisms, and management. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 40.

Olgin J, Zipes DP. Specific arrhythmias: diagnosis and treatment. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 39.

Zimetbaum P. Cardiac arrhythmia with supraventricular origin. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 64.

Update Date: 6/22/2012

Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Michael A. Chen, MD, PhD, Assistant Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.