In sinus exit block, the typical pause length is how many P-P intervals?

In sinus exit block, the typical pause length is how many P-P intervals?

• A. Equal to P-P interval
• B. Twice the P-P interval
• C. Three times the P-P interval
• D. Half the P-P interval

Answer: (B)

Sinus exit block happens when the SA node fires but the impulse cannot exit to atrial tissue for one cycle. That blocked attempt creates a pause so that the next conducted beat arrives after an additional full P-P interval. In other words, the last P wave before the block and the next P wave after resumption are separated by two P-P intervals. So the typical pause length is twice the P-P interval. Shorter (equal to one P-P) would be normal rhythm; longer (three P-P) would imply a different or more prolonged disruption.

Sinus exit block happens when the SA node fires but the impulse cannot exit to atrial tissue for one cycle. That blocked attempt creates a pause so that the next conducted beat arrives after an additional full P-P interval. In other words, the last P wave before the block and the next P wave after resumption are separated by two P-P intervals. So the typical pause length is twice the P-P interval. Shorter (equal to one P-P) would be normal rhythm; longer (three P-P) would imply a different or more prolonged disruption.