What is the primary characteristic of atrial fibrillation?

Atrial fibrillation is primarily characterized by an irregular and rapid heart rate. This condition occurs when the electrical signals in the atria, the upper chambers of the heart, become disorganized, leading to an erratic heartbeat. Instead of a consistent, rhythmic beat, the heart experiences quivering or a rapid, unsynchronized contraction of the atria. As a result, the ventricular response can also be rapid and irregular.

This irregularity can lead to various symptoms, including palpitations, dizziness, and fatigue, and it also increases the risk of stroke due to ineffective blood flow in the atria. The nature of atrial fibrillation distinguishes it clearly from other heart rhythm abnormalities, which may include a slow or steady heart rate, both of which do not align with the hallmark features of this arrhythmia.