General Information

DEFINITION--A completely irregular heartbeat rhythm. Fibrillation means a quivering of heart-muscle fibers.

BODY PARTS INVOLVED--Heart muscles; the atrium (also called auricle), a chamber of the heart that connects to the left ventricle (main chamber); heart's electrical conduction system.

SEX OR AGE MOST AFFECTED--Adults of both sexes.

SIGNS & SYMPTOMS

• No symptoms (sometimes).
• Continuously irregular heartbeat, in which no 2 beats are of equal strength or duration.
• Weakness, dizziness or faintness (sometimes).

CAUSES

• Rheumatic heart disease caused by rheumatic fever.
• Atherosclerosis of coronary arteries, with or without a previous heart attack.
• Hyperthyroidism.
• Congestive heart failure.

RISK INCREASES WITH

• Stress.
• Heart valve disease.
• Recent heart surgery.
• Electrolyte disturbances, especially low potassium.
• Pulmonary embolism.
• Excessive use of some drugs, such as thyroid hormones, caffeine and others.
• Smoking.
• Excess alcohol consumption.
• Obesity.

HOW TO PREVENT--Avoid risk factors for atherosclerosis and coronary-artery disease (both in Illness section).

What To Expect

DIAGNOSTIC MEASURES--

• Your own observation of symptoms.
• Medical history and physical exam by a doctor.
• ECG (See Glossary).
• Blood studies to measure levels of drugs used in treatment.

APPROPRIATE HEALTH CARE

• Self-care after diagnosis.
• Doctor's treatment.
• Hospitalization (sometimes).
• Electric shock (electrocardioversion), which may restore normal rhythm.

POSSIBLE COMPLICATIONS

• Acute pulmonary edema.
• Arterial thrombosis or embolus.
• Congestive heart failure.
• Other heartbeat irregularities, triggering cardiac arrest.

PROBABLE OUTCOME--A normal heartbeat rhythm can be restored with electrocardioversion in about 50% of patients. In the other 50%, some symptoms can be controlled with medication. Those whose rhythm is restored to normal have a longer life expectancy, greater strength and more energy than those who have continuing atrial fibrillation.

How To Treat

GENERAL MEASURES--

• Have family members and friends learn cardiopulmonary resuscitation (CPR) in case you have cardiac arrest.
• Don't smoke, use mind-altering drugs or drink more than 1 or 2 alcoholic drinks--if any--a day.
• Learn to check your own pulse for rate (beats per minute), rhythm (regular or irregular) and strength. Call your doctor if these change.
• See How to Cope with Stress in Appendix section.
• See Resources for Additional Information.

MEDICATION--Your doctor may prescribe:

• Heart medications, such as digitalis, quinidine, calcium-channel blockers or beta-adrenergic blockers to regulate the heartbeat.
• Anticoagulants to prevent blood clot.
• Avoid non-prescription decongestants.

ACTIVITY-- Resume your normal activities as soon as symptoms improve. Consult your doctor before resuming sexual relations.

DIET--

• Lose weight if you are obese, but don't use appetite suppressants. These may worsen rhythm disturbances. See Weight Loss diet in Appendix section.
• The underlying heart condition may require a low-salt or low-fat diet (see diets in Appendix section) and potassium supplements.

Call Your Doctor If