Which statement describes second-degree AV block type II on telemetry?

Which statement describes second-degree AV block type II on telemetry?

• A. Progressive PR prolongation followed by a dropped QRS in a repeating pattern
• B. Atria and ventricles beat independently with no fixed P-QRS
• C. Intermittent dropped QRS after a normal PR interval
• D. Intermittent dropped QRS without prior PR prolongation; more likely to progress to complete block

Answer: (D)

Second-degree AV block type II is defined by intermittent failure of conduction that occurs without prior widening of the PR interval. In telemetry, you’ll see P waves that are not followed by a QRS complex, but the PR interval of the beats that do conduct remains constant. This pattern reflects a block below the AV node (often in the His-Purkinje system) and carries a higher risk of progressing to complete heart block, which is why it’s treated as a more serious finding requiring pacing. So, the statement describing intermittent dropped QRS without prior PR prolongation and noting a higher likelihood of progression to complete block matches Mobitz II. The other patterns describe different conditions: progressive PR prolongation with a later dropped beat is typical of Mobitz I (Wenckebach); complete dissociation with no fixed P–QRS relationship describes a higher-grade block (third-degree); and a dropped QRS after a normal PR interval without emphasizing progression risk is not as characteristic of Mobitz II.

Second-degree AV block type II is defined by intermittent failure of conduction that occurs without prior widening of the PR interval. In telemetry, you’ll see P waves that are not followed by a QRS complex, but the PR interval of the beats that do conduct remains constant. This pattern reflects a block below the AV node (often in the His-Purkinje system) and carries a higher risk of progressing to complete heart block, which is why it’s treated as a more serious finding requiring pacing.

So, the statement describing intermittent dropped QRS without prior PR prolongation and noting a higher likelihood of progression to complete block matches Mobitz II. The other patterns describe different conditions: progressive PR prolongation with a later dropped beat is typical of Mobitz I (Wenckebach); complete dissociation with no fixed P–QRS relationship describes a higher-grade block (third-degree); and a dropped QRS after a normal PR interval without emphasizing progression risk is not as characteristic of Mobitz II.