Which of the following arrhythmias is characterized by a regular, fast heart rate?

Atrial flutter is characterized by a regular, often rapid heart rate, typically ranging from 240 to 340 beats per minute. This arrhythmia occurs due to a distinct electrical circuit within the right atrium, leading to a repetitive stimulation of the atria. As a result, the heart maintains a regular rhythm, but at an increased rate, which is a hallmark of atrial flutter.

This condition stands out among the listed options because it specifically presents with a structured and consistent rhythm, making it easily identifiable on an ECG. In contrast, ventricular fibrillation is chaotic and irregular, leading to ineffective heart contractions, while bradycardia refers to a slower than normal heart rate. Asystole represents a complete absence of electrical activity, resulting in no heart contractions. Thus, atrial flutter is the only option that aligns with the description of a regular, fast heart rate.