Describe atrial fibrillation.

Atrial fibrillation is characterized by an irregular and often rapid heart rate that arises as a result of chaotic electrical signals in the atria of the heart. This arrhythmia disrupts the coordinated contractions of the atria, leading to ineffective pumping of blood into the ventricles. In atrial fibrillation, instead of a regular rhythm, the atrial contractions become disorganized, causing the heart to beat in an erratic manner. This can lead to symptoms such as palpitations, shortness of breath, and fatigue, and it significantly increases the risk of stroke due to the potential for blood clots forming in the atria as they fail to contract effectively. Thus, the description of atrial fibrillation as an irregular and often rapid heart rate due to chaotic electrical signals is accurate and illustrates the key physiological disturbances associated with the condition.