Atrial Fibrillation
Atrial fibrillation (also known as A Fib or AF) is an electrical disturbance of the top chambers that results in a very rapid, disorganized, chaotic atrial signal at rates up to 400 beats per minute. The rapid signals bombard the AV node, which tends to pass random signals through to the ventricles. The net result is that the patient's pulse is irregular with no set pattern. It may be irregular and rapid, irregular and slow, and everything in between. The heart rate also tends to jump up quickly with only low level of exercise.
Atrial fibrillation can occur intermittently, which is known as Paroxysmal Atrial Fibrillation (it comes and goes, and can last from seconds to days). On the other hand, it can be "Persistent AF" (meaning it doesn't stop on its own). When atrial fibrillation has been present for many months and there's little hope of restoring a normal rhythm, it may be considered "Permanent AF". The overall rate of the ventricles varies tremendously, depending on the age of the patient, the health of the AV node, and whether medications to slow AV conduction (such as calcium-channel blockers or beta blockers) are prescribed. Sometimes atrial fibrillation is caused by other conditions such as an overactive thyroid or excessive alcohol use. Sometimes it is associated with cardiac conditions such as coronary artery disease, high blood pressure, congestive heart failure, or valvular heart disease. Occasionally, it occurs in the absence of other cardiac conditions and is then called "lone" atrial fibrillation.
Usually medicines are initially required to control the heart rate, and the goal is usually to restore a normal heart rhythm. Sometimes, the only way to stop the disorganized activity of the atrium is to get a large portion of all the atrial tissue to fire at the same time. This is done by giving the patient deep sedation and then delivering an electrical shock across the chest in a procedure known as "electrical cardioversion." The shock stops the abnormal atrial activity and allows the normal sinus rhythm to take over again. This is considered a relatively safe procedure and the patient will not remember anything. It is usually effective unless the atrial fibrillation has been present for months or years or unless the underlying heart disease is very severe. Unfortunately, the atrial fibrillation may recur in the future so medications are usually needed to help maintain a normal sinus rhythm.
Patients who have atrial fibrillation may be at increased risk of developing a blood clot within the nooks and crannies found in the atrial chambers (particularly the left atrial appendage, which is an outpouching of the atrial muscle. If such a blood clot breaks off and travels in the circulatory system, it can lead to a stroke. Strokes due to atrial fibrillation are very serious, and make up about 15% of all strokes. Risk factors for stroke include age over 65, hypertension, diabetes, vascular disease, heart failure, or history of a prior stroke. If you have atrial fibrillation with two or more of these risk factors, your doctor may recommend a blood thinner to reduce your risk of serious stroke.
Invasive electrophysiology treatments are available that can help patients with atrial fibrillation. Catheter ablation can eliminate atrial fibrillation for many years in about 80% of patients, and a new technique called "Pulsed Field Ablation" or PFA is a shorter, safer procedure than the conventional radiofrequency ablation procedure used in the past. Another cutting-edge treatment is to deliver a heart device to close off the left atrial appendage. Several companies produce such Left Atrial Occlusion Devices, which are able to reduce the risk of stroke and eliminate the need to take a blood thinner.