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Alternative namesAuricular fibrillation; A-fib
DefinitionAtrial fibrillation/flutter is a heart rhythm disorder (arrhythmia). It usually involves a rapid heart rate , in which the upper heart chambers (atria) are stimulated to contract in a very disorganized and abnormal manner.
Causes, incidence, and risk factors
Arrhythmias are caused by a disruption of the normal functioning of the electrical conduction system of the heart. Normally, the atria and ventricles contract in a coordinated manner.
In atrial fibrillation and flutter, the atria are stimulated to contract very quickly and differently from the normal activity originating from the sinoatrial node. This results in ineffective and uncoordinated contraction of the atria in atrial fibrillation, and in a peculiarly organized contraction pattern in atrial flutter.
In atrial flutter, however, the ventricles may beat rapidly, but regularly. If the atrial fibrillation/flutter is part of a condition called sick sinus syndrome, the ventricles may beat more slowly than normal. Thus, during atrial fibrillation the ventricles, by beating too fast or too slow, may fail to pump enough blood to meet the needs of the body.
Hyperthyroidism , hypertension , and other diseases can cause arrhythmias, as can recent heavy alcohol use (binge drinking). Some cases of atrial fibrillation or flutter occur in the setting of a heart attack or soon after surgery on the heart.
Note: Symptoms may begin and/or stop suddenly.
Signs and testsListening to the heart with a stethoscope shows an irregular rhythm. The pulse may feel rapid, irregular, or both. Sometimes the pulse is too slow. The normal heart rate is 60 to 100, but in atrial fibrillation/flutter the heart rate may be 100 to 175. Blood pressure may be normal or low.
An ECG shows atrial fibrillation or atrial flutter. Continuous ambulatory cardiac monitoring -- Holter monitor (24 hour test) -- may be necessary because the condition is often sporadic (occurring at some times but not others).
Tests to determine the presence of underlying heart diseases may include:
In certain cases, atrial fibrillation may require emergency treatment to convert the arrhythmia to normal (sinus) rhythm, either with electrical cardioversion or with the administration of intravenous drugs, such as dofetilide or ibutilide.
Long-term treatment varies depending on the cause of the atrial fibrillation or flutter. Medication may include beta-blockers, calcium channel blockers, digitalis or other medications (such as anti-arrhythmic drugs) which slow the heartbeat or slow conduction of the impulse from the atria to the ventricles.
Medications may also include blood thinners, such as heparin or coumadin, to reduce the risk of a thromboembolic event such as a stroke.
Some selected patients with atrial fibrillation, rapid heart rates, and intolerance to medication may require a catheter procedure on the atria called radiofrequency ablation.
For most patients with atrial flutter, radiofrequency ablation is the current treatment of choice. Some patients with atrial fibrillation and rapid heart rates may need the radiofrequency ablation done not on the atria, but directly on the AV junction (i.e., the area that normally filters the impulses coming from the atria before they proceed to the ventricles).
Ablation of the AV junction leads to complete heart block. These patients then require a permanent pacemaker.
Expectations (prognosis)The disorder is usually controllable with treatment. The natural tendency of atrial fibrillation, however, is to become a chronic condition.
Calling your health care providerCall your health care provider if symptoms indicate atrial fibrillation or flutter may be present.
PreventionFollow the health care provider's recommendations for the treatment of underlying disorders. Avoid binge drinking.
Update Date: 5/10/2002Elena Sgarbossa, M.D., Department of Cardiology, Rush-Presbyterian St. Luke's Medical Ctr., Chicago, IL. Review provided by VeriMed Healthcare Network.
Last updated: Tue, 06 Jan 2009 00:20:03 GMT