Define "tachycardia" in relation to atrial fibrillation.

Tachycardia, in relation to atrial fibrillation, refers to an abnormally fast heart rhythm, which is a key characteristic of this condition. Atrial fibrillation causes the heart's electrical signals to become disorganized, leading to a rapid and irregular heartbeat. This disruption can result in heart rates that exceed 100 beats per minute, classifying the rhythm as tachycardia.

Understanding this concept is crucial because tachycardia in atrial fibrillation can lead to various complications, including increased risk of stroke and heart failure, and may require management strategies such as rate control or rhythm control medications. Recognizing the connection between atrial fibrillation and tachycardia helps in both diagnosis and treatment planning for patients experiencing this arrhythmia.