Which rhythm can present with a pulse that is either regular or irregular?

• A. Atrial Tachycardia
• B. Atrial Flutter
• C. Atrial Fibrillation
• D. Junctional Tachycardia

Answer: (B)

The pulse pattern depends on how the atrial rate relates to the ventricular response through AV nodal conduction. In atrial flutter, the atrial activity is usually very regular, but how fast the ventricles beat depends on how many atrial impulses get through the AV node. If the AV node conducts with a fixed ratio (like 2:1 or 3:1), the ventricular rhythm and pulse stay regular. If conduction varies or block occurs intermittently, the ventricular rate becomes irregular, making the pulse irregular. That combination—regular atrial rhythm with either regular or irregular ventricular response—lets the pulse be either regular or irregular in atrial flutter.

By contrast, atrial tachycardia generally presents with a regular pulse due to a stable ventricular response, atrial fibrillation typically produces an irregularly irregular pulse due to chaotic atrial activity with variable conduction, and junctional tachycardia usually has a regular rhythm with a consistent conduction pattern.