Atrial Fibrillation - Causes, Symptoms, Treatment
Atrial Fibrillation may increase mortality up to 2-fold, primarily due to embolic stroke. This risk exists as the lack of coordinated atrial contraction leads to unusual fluid flow states through the atrium that are permissive for formation of thrombus that is then at risk to embolize. This risk is theoretically particularly present upon return to normal sinus rhythm when coordinated atrial contraction can entrain a thrombus into flow. The risk of embolism associated with cardioversion is stated to be as high as 2%. Thus, part of the challenge for emergency physicians is the question of managing rate versus rhythm in the ED and the issue of when cardioversion through any mechanism should be attempted.Atrial fibrillation (AF or Afib) is the most common type of irregular heartbeat. It is found in about 2.2 million Americans. It increases with age. If you have AF, the impulse does not travel in an orderly fashion through the atria. Instead, many impulses begin simultaneously and spread through the atria and compete for a chance to travel through the AV node.
Causes
Atrial fibrillation (AF) occurs when the electrical signals traveling through the heart are conducted abnormally and become disorganized and very rapid. This is the result of damage to the heart’s electrical system. This damage is most often the result of other conditions, such as coronary artery disease or high blood pressure, that affect the health of the heart. Sometimes, the cause of AF is unknown.
Symptoms
Symptoms of atrial fibrillation vary from person to person. A number of people have no symptoms. The most common symptom in people with intermittent atrial fibrillation is palpitations, a sensation of rapid or irregular heartbeat. This may make some people very anxious. Many people also describe an irregular fluttering sensation in their chests.
Treatment
The main goals of treatment of atrial fibrillation are to prevent temporary circulatory instability and to prevent stroke. Rate and rhythm control are principally used to achieve the former, while anticoagulation may be required to decrease the risk of the latter. In emergencies, when circulatory collapse is imminent due to uncontrolled tachycardia, immediate cardioversion may be indicated. The primary factors determining atrial fibrillation treatment are duration and evidence of hemodynamic instability.
Medications are used to slow down rapid heart rate associated with AF. These treatments may include drugs such as digoxin, beta blockers (atenolol, metoprolol, propranolol), amiodarone, disopyramide, calcium antagonists (verapamil, diltiazam), sotalol, flecainide, procainamide, quinidine, propafenone, etc. Electrical cardioversion may be used to restore normal heart rhythm with an electric shock, when medication doesn’t improve symptoms.
For atrial fibrillations caused by abnormal heart tissue, catheter radiofrequency ablation can be used to destroy the abnormal tissue. The procedure is performed without open chest surgery. In the procedure, catheters (thin, flexible tubes) are threaded through the patient’s blood vessels to reach the abnormal heart tissue. The cardiologist then uses a small cutter or radiofrequency energy to remove the abnormal tissue.
