Where does atrial flutter originate?

Where does atrial flutter originate?

• A. Atrioventricular node
• B. Atrial automaticity focus
• C. Sinus node
• D. Ventricular pacemaker

Answer: (B)

Atrial flutter originates from an atrial automaticity focus, which is a specific area within the atria that has the capacity to initiate and propagate electrical impulses independently. This abnormal rhythm typically originates in the right atrium, often due to a reentrant circuit, such as around the tricuspid valve. The automaticity focus can generate rapid electrical signals, leading to a characteristic "sawtooth" pattern of atrial contractions, best observed on an EKG as "F-waves" or flutter waves.

In contrast, while the atrioventricular node has an important role in coordinating conduction between the atria and ventricles, it is not the site of origin for atrial flutter. The sinus node is the primary pacemaker of the heart, but in atrial flutter, its usual rhythm is disrupted. Finally, a ventricular pacemaker is not involved in atrial flutter since it primarily regulates ventricular contractions, which occur independently of the atrial flutter mechanism. Understanding the specific origins of arrhythmias is crucial for effective diagnosis and treatment in clinical practice.