heart and blood vessel disorders
Atrial Fibrillation and Atrial Flutter
Treatment of Atrial Fibrillation and Atrial Flutter
Slowing the heart rate Anticoagulants Restoring normal heart rhythm Ablation Treatment of atrial fibrillation or atrial flutter is designed to control the rate at which the ventricles contract, to restore the normal rhythm of the heart, and to treat the disorder causing the arrhythmia. Drugs to prevent the formation of blood clots and emboli (anticoagulants oraspirin) are usually given. Treatment of the underlying disorder is important but does not always alleviate atrial arrhythmias. However, treatment of an overactive thyroid gland or surgery to correct a heart valve disorder or a birth defect of the heart may help. Usually, the first step in treating atrial fibrillation or atrial flutter is to slow the beating of the ventricles so that the heart pumps blood more efficiently. Usually, drugs can slow the ventricle. Often, the first drug tried is a calcium channel blocker, such asdiltiazemorverapamil, which may slow the conduction of impulses to the ventricles (see table). A beta-blocker, such aspropranololoratenolol, may be used. For people who have heart failure,digoxinmay be used. Atrial fibrillation or atrial flutter may spontaneously convert to a normal rhythm. In some people, these arrhythmias must be actively converted to a normal rhythm ( Cardioversion-Defibrillation ). Such people include those in whom the atrial fibrillation or atrial flutter causes heart failure or other symptoms of low heart output. Before restoring normal rhythm, because there is a risk that a blood clot will break off and cause a stroke during conversion, measures must be taken to prevent blood clots. If the atrial fibrillation or atrial flutter has been present for more than 48 hours, doctors give an anticoagulant, such aswarfarin, for 3 to 4 weeks before attempting conversion. Alternatively, doctors can give a short-acting anticoagulant, such asheparin, and do echocardiography. If echocardiography does not show a clot in the heart, the person can undergo conversion immediately. If the rhythm has clearly been present less than 48 hours, people do not need an anticoagulant before conversion. However, most people need an anticoagulant for at least 4 weeks after conversion. Methods of conversion include Electrical shock (synchronized cardioversion) Drugs to the heart is the most effective approach. The electrical shock is synchronized to be given only at a certain point in the heart's electrical activity (synchronized Cardioversion-Defibrillation ) so that it does not cause ventricular fibrillation. Cardioversion is effective in 75 to 90% of people. Certainantiarrhythmic drugs(most commonly,amiodarone,flecainide,procainamide,propafenone, orsotalol—see table) also may restore a normal rhythm. However, these drugs are effective in only about 50 to 60% of people and often cause side effects. Conversion to a normal rhythm by any means becomes less likely the longer the arrhythmia has been present (especially after 6 months or more), the larger the atria become, and the more severe the underlying heart disorder becomes. When conversion is successful, the risk of recurrence is high, even if people are taking a drug to prevent recurrence (typically one of the same drugs used to convert the arrhythmia to a normal rhythm). Rarely, when all other treatments of atrial fibrillation are ineffective, the atrioventricular node can be destroyed by Destroying Abnormal Heart Tissue (Ablation) . Ablation is a process to kill a specific area of abnormal tissue using energy from radiofrequency waves, lasers, or electrical current, or by applying very cold temperatures. These are applied using a catheter inserted into the heart. By destroying the AV node, this ablation procedure completely stops conduction from the atria to the ventricles. Thus, although the atria continue to fibrillate, the ventricular rate slows down. However, a permanent Artificial Pacemakers is required to activate the ventricles afterward. Another type of ablation procedure for atrial fibrillation destroys atrial tissue near the pulmonary veins (pulmonary vein isolation). Pulmonary vein isolation spares the atrioventricular node and can stop the atrial fibrillation but is less often successful (60 to 80%), and the risk of serious complications is significant (1 to 5%). Accordingly, this procedure is often reserved for the best candidates (such as, younger people who have no significant heart disease like a heart valve disorder, people without other options such as those with atrial fibrillation that does not respond to drug therapy, or people with Heart Failure (HF) . For people who have atrial flutter, ablation may be used to interrupt the flutter circuit in the atrium and permanently re-establish normal rhythm. This procedure is successful in about 90% of people. Measures to prevent blood clots (and thus prevent Overview of Stroke ) are necessary when atrial fibrillation or atrial flutter is converted back to normal rhythm. Most people also usually need such measures during long-term treatment. Doctors typically give an Otherwise healthy people who had only one episode of atrial fibrillation that converted to normal rhythm (spontaneously or with treatment) need anticoagulant treatment for only 4 weeks. People who had several episodes of atrial fibrillation or atrial flutter or who remain in such rhythms despite treatment should take a drug to prevent blood clots indefinitely. Doctors usewarfarinor other anticoagulants for people who have one or more risk factors for developing stroke. Such risk factors include Age 65 years or older High blood pressure Diabetes Heart failure A previous stroke or transient ischemic attack Disease affecting the blood vessels Being female Some people without those risk factors are givenaspirin, and some are not given any treatment to prevent strokes. Even after atrial fibrillation or atrial flutter converts to normal rhythm, doctors usually continue anticoagulant treatment, often for the remainder of the person’s life. This anticoagulant treatment is needed because the arrhythmia may come back without the person being aware of it. Dangerous blood clots can form during these episodes. 