Patient Care Technician (PCT) AAH Practice Exam

How many P waves are typically seen in a 2nd-degree block type 2 compared to QRS complexes?

1. More QRS complexes than P waves

2. Equal number of P waves and QRS complexes

3. More P waves than QRS complexes

4. No P waves are visible

The correct answer is: More P waves than QRS complexes

In a 2nd-degree block type 2, also known as Mobitz type II, there is an essential characteristic where there are more P waves than QRS complexes. This occurs because, in this type of heart block, some of the P waves fail to result in a corresponding QRS complex (the electrical impulse does not successfully conduct through the AV node). Typically, the conduction is consistent, meaning that the QRS complexes occur after a set number of P waves; however, there is a regular pattern where some P waves are not followed by QRS complexes. As a result, for every few P waves, there will be fewer QRS complexes. In summary, the distinguishing feature of a 2nd-degree block type 2 involves a ratio where there are indeed more P waves present than QRS complexes, making this statement accurate in identifying the characteristic electrical activity of the heart during this condition.