What does the P wave look like with 2nd-degree AV block type 2?

Prepare for the Cleveland Clinic EKG Test with flashcards and multiple choice questions. Gain insights with hints and explanations. Ace your exam today!

Multiple Choice

What does the P wave look like with 2nd-degree AV block type 2?

Mobitz II blocks have conduction failure below the AV node, in the His-Purkinje system. The P waves themselves stay normal in appearance, but some P waves are not followed by a QRS complex, creating dropped beats. Importantly, when a beat is conducted, the PR interval before it remains constant—there is no progressive lengthening like you see in Mobitz I. So the characteristic pattern is normal-looking P waves with occasional non-conducted P waves (dropped beats) and a constant PR interval for the conducted beats. This is why the best description is a dropped beat with a constant PR interval, reflecting a block below the AV node.

Mobitz II blocks have conduction failure below the AV node, in the His-Purkinje system. The P waves themselves stay normal in appearance, but some P waves are not followed by a QRS complex, creating dropped beats. Importantly, when a beat is conducted, the PR interval before it remains constant—there is no progressive lengthening like you see in Mobitz I. So the characteristic pattern is normal-looking P waves with occasional non-conducted P waves (dropped beats) and a constant PR interval for the conducted beats. This is why the best description is a dropped beat with a constant PR interval, reflecting a block below the AV node.

More practice questions