Atrial fibrillation (a fib or sometimes AF) is a condition when the atria of the heart beat quickly, irregularly and out of sync with the ventricles. On the EKG, there is no definite p wave. The contraction of the ventricles may also be irregular (irregular R-R interval). Irregular contraction of the atria can promote blood pooling and small blood clots, which can be a cause of stroke. It can also affect the heart rate or cardiac output, leading to lightheadedness or difficulty breathing.
Atrial fibrillation can be managed in different ways. The maximum heart rate can be governed by medications. This is called rate control, and medicines like a calcium channel or beta receptor blocker may be used. The electrical circuits within the atria can be disrupted (catheter ablation). Electrical shock can be used to reset the electrical timing (cardioversion). Medications can be used to prevent blood clots and stroke (anticoagulation, with warfarin, apixaban, dabigatran, bivalirudin, etc.)
Atrial fibrillation is caused by changes in the electrical conduction circuit within the atria. This can be related to age, high blood pressure, or coronary artery disease. Changes in the valves of the heart can also cause atrial fibrillation. These include mitral valve stenosis or regurgitation. Heart failure and thickening of the heart can be related to atrial fibrillation. Changes in the blood chemistry, such as high alcohol or low magnesium, caffeine and a history of diabetes mellitus are also associated with atrial fibrillation.