What is the primary characteristic of type 2 second degree AV block?

• A. The PR interval lengthens before a dropped QRS
• B. All impulses are conducted normally
• C. It may require placement of a pacemaker
• D. It is more common than type 1

Answer: (C)

The primary characteristic of type 2 second-degree AV block is that it may require the placement of a pacemaker. This type of block is characterized by a sudden drop of QRS complexes without a preceding lengthening of the PR interval, which distinguishes it from type 1. In type 2 block, there can be significant disruptions in the conduction system that can lead to bradycardia or even complete heart block, posing a risk to the patient’s health.

The necessity for a pacemaker arises from the irregular conduction that results in missed beats, meaning the heart does not pump efficiently, which can lead to symptoms like fatigue, dizziness, or even syncope. Constant monitoring or a permanent pacemaker may be needed to stabilize the heart rhythm and prevent further complications. This is especially crucial since the block can progress to more severe arrhythmias that could be life-threatening without intervention.

In contrast, while it may be true that the other options present some understanding of AV blocks, they do not accurately capture the critical need for intervention that characterizes type 2 second-degree AV block.