A sinus pause or arrest is defined as an interruption of at least how many seconds?

• A. At least 2 seconds
• B. At least 1 second
• C. At least 3 seconds
• D. At least 4 seconds

Answer: (A)

Sinus pause or arrest occurs when the SA node temporarily stops firing, so there’s a pause with no P waves and no QRS complexes for a period. The key point is how long that interruption lasts. If the pause is at least 2 seconds, it’s long enough to be considered a pathological sinus pause/arrest rather than a normal beat-to-beat variation. A 2-second pause reflects SA node dysfunction and can lead to symptoms or require evaluation for sick sinus syndrome. Shorter pauses can occur normally after a premature beat or other benign variations, so they aren’t labeled as sinus arrest.