Which description matches 2nd-degree AV block type 2?

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Multiple Choice

Which description matches 2nd-degree AV block type 2?

In second-degree AV block type II, some atrial impulses are blocked before reaching the ventricles, so you see occasional dropped QRS complexes. The key feature is that the PR interval on the conducted beats stays constant from one to the next, not progressively lengthening before a drop. This pattern distinguishes it from blocks where the PR interval lengthens stepwise (Wenckebach or Mobitz I) before a beat is dropped. So the description that matches is a dropped beat with a constant PR interval. In contrast, a dropped beat with a prolonged PR interval points to the progressive PR prolongation of Mobitz I, a pattern of Wenckebach. If there are no P waves, that suggests a higher-grade block with AV dissociation, often a complete heart block. Clinically, Mobitz II is more likely to progress to complete heart block and often requires pacing.

In second-degree AV block type II, some atrial impulses are blocked before reaching the ventricles, so you see occasional dropped QRS complexes. The key feature is that the PR interval on the conducted beats stays constant from one to the next, not progressively lengthening before a drop. This pattern distinguishes it from blocks where the PR interval lengthens stepwise (Wenckebach or Mobitz I) before a beat is dropped.

So the description that matches is a dropped beat with a constant PR interval. In contrast, a dropped beat with a prolonged PR interval points to the progressive PR prolongation of Mobitz I, a pattern of Wenckebach. If there are no P waves, that suggests a higher-grade block with AV dissociation, often a complete heart block. Clinically, Mobitz II is more likely to progress to complete heart block and often requires pacing.

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