AEMCA Practice Exam

What characterizes Mobitz type 2 heart block?

1. The AV node is blocked completely.

2. Only some impulses are allowed through the AV node.

3. Heart rate is significantly elevated.

4. QRS complexes occur without P waves.

The correct answer is: Only some impulses are allowed through the AV node.

Mobitz type 2 heart block is characterized by the intermittent failure of some electrical impulses to pass through the atrioventricular (AV) node. In this condition, while some impulses do successfully get through to the ventricles, others are blocked, causing a periodic dropping of QRS complexes. This results in a situation where the conduction through the AV node is partially impaired rather than completely blocked, as seen in other types of blocks. Understanding this distinction is crucial because it indicates that patients with Mobitz type 2 typically have a stable ventricular rate unless they progress to a higher degree of block. The condition can lead to the risk of progression to more severe heart block during the arrhythmia, but it remains significant that there is partial conduction. The other options reflect misunderstandings of this specific type of block. A complete block of all impulses would be indicative of a different condition. An elevated heart rate is often not characteristic of Mobitz type 2, as the heart rate typically remains relatively regular but can be affected by the level of blockage. Lastly, while there may be instances of missing QRS complexes due to blocked impulses, the presence of P waves is still observed, as they are associated with atrial depolarization and may not correlate