Atrial fibrillation and flutter

Causes and Risks:
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. This results in ineffective and uncoordinated contraction of the atria.

The impulses may be transmitted to the ventricles in an irregular fashion, or only some of the impulses may be transmitted. This causes the ventricles to beat more rapidly than normal, resulting in a rapid or irregular pulse . The ventricles may fail to pump enough blood to meet the needs of the body.

Causes of atrial fibrillation and flutter include dysfunction of the sinus node (the "natural pacemaker" of the heart) and a number of heart and lung disorders including coronary artery disease , rheumatic heart disease , mitral valve disorders, pericarditis , and others. Hyperthyroidism , hypertension , and other diseases can cause arrhythmias, as can recent heavy alcohol use (binge drinking). Some cases have no identifiable cause. Atrial flutter is most often associated with a heart attack ( myocardial infarction ) or surgery on the heart.

Atrial fibrillation or flutter affects about 5 out of 1000 people. It can affect either sex. Atrial fibrillation is very common in the elderly, but it can occur in persons of any age.

Prevention:
Follow the health care provider's recommendations for the treatment of underlying disorders. Avoid binge drinking.

Symptoms:

Note: Symptoms may begin and/or stop suddenly.

Signs and Tests:
Listening with a stethoscope ( auscultation ) of the heart shows a rapid or irregular rhythm. The pulse may feel rapid or irregular. 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 (sudden beginning and ending of episodes of the arrhythmia ).

Tests to determine the cause may include:



Treatment:
Treatment varies depending on the cause of the atrial fibrillation or flutter. Medication may include digitalis or other medications that slow the heart beat or that slow conduction of the impulse to the ventricles.

Electrical cardioversion may be required to convert the arrhythmia to normal (sinus) rhythm.

Prognosis:
The disorder is usually controllable with treatment. Atrial fibrillation may become a chronic condition. Atrial flutter is usually a short-term problem.

Complications:

  • incomplete emptying of the atria which can reduce the amount of blood the heart can pump
  • emboli to the brain ( stroke ) or elsewhere--rare



Call Your Healthcare Provider:
Call your health care provider if symptoms indicate atrial fibrillation or flutter may be present.