Atrial Fibrillation (A Fib)
A Fib is an arrhythmia, or abnormal heart rhythm, characterized by a rapid and irregular pulse. It can be paroxysmal (starting and stopping on its own) or persistent. The natural history is progress, initially being paroxysmal and ultimately persisting over time. It is the most common arrhythmia occurring in more than two million Americans. It is more common as people get older, partcularly in the presence of heart disease, high blood pressure and diabetes, but can occur in young people with structurally normal hearts.
It can be uncomfortable with symptoms that include palpitations, fatigue, chest discomfort and shortness of breath, said Dr. Darren Peress, an electrophysiologist specializing in cardiac rhythm management and the EP Lab medical director. Some people have no symptoms at all and others are highly symptomatic and unable to function.
It can result in heart failure. Much like when you run too fast for too long your legs will get tired, if your heart beats too fast for too long, it can become weak, explained Dr. Peress.
Atrial fibrillation increases your risk of stroke significantly. Because the atria are quivering and not contracting normally, blood can pool in a pocket of the left atrium called the left atrial appendage. That clot can break free and travel through the circulation to the brain and result in a stroke.
Management of atrial fibrillation consists of either rate or rhythm control. Rate control does not involve any attempt to suppress the atrial fibrillation itself but rather attempts to prevent one’s heart rate from being excessively fast, thereby controlling symptoms. Rhythm control attempts to keep the heart in a normal rhythm with the use of electrical cardioversion, antiarrhythmic drugs and sometimes ablation.
Cardioversion is a procedure performed to stop atrial fibrillation and restore a normal rhythm. It is an outpatient procedure, performed in the hospital. While the patient is briefly sedated, an electrical current is delivered between two patches (on the front and back of the chest) restoring a normal sinus rhythm. The most significant risk of the procedure is stroke but this risk is exceedingly low as long as the patient has been anticoagulated with Coumadin for three weeks prior to the procedure (with an INR over 2) or have had a transesophageal echocardiogram (TEE) before the procedure to make sure there is no clot in the left atrial appendage of the heart. While cardioversion is highly successful in restoring a normal rhythm, there is a chance atrial fibrillation can recur over time.
Antiarrhythmic drugs can then be used to help maintain a normal rhythm, and to help prevent the atrial fibrillation from recurring. There are numerous drugs available, commonly including flecainide (tambocor), propa fenone (rhythmol), sotalol (betapace), dofetilide (tikosyn) and amiodarone (cordarone, pacerone). These drugs typically help but are not 100% effective, and can have significant side effects.
When drug therapy is ineffective or poorly tolerated, catheter ablation can be performed. Atrial fibrillation is usually induced by high frequency electrical triggers within the pulmonary veins, four veins that drain blood into the left atrium from from the lungs. Pulmonary vein isolation is a procedure whereby these veins are electrically isloated from the left atrium with radiofrequency energy, preventing pulmonary vein triggers from entering the heart and inducing atrial fibrillation. This is successful the majority of the time.
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