1. The AV blocks are caused when the conduction of the supraventricular impulses through the AV node or the ventricular portion of the electrical conduction system is either ___________ or ____________ blocked.
2. When the impulses are delayed but still transmitted to the ventricles, it is called a _______-degree AV block.
3. When the supraventricular impulses are intermittently blocked from reaching the ventricles causing some blocked P waves, it is called a ________-degree AV block.
4. When there is no communication at all between the atria and the ventricles, we call it a ____________ or _________-degree AV block.
5. The second-degree AV blocks include various variations. These are:
A. Mobitz I or Wenckebach
B. 2:1
C. Mobitz II
D. High-grade or advanced
E. All of the above
6. The typical finding in a first-degree AV block is a prolonged PR interval with a width greater than _______ seconds.
7. Since the block in first-degree AV block usually occurs in the AV node, the QRS complexes are usually narrow and the conduction ratio is 1:1 between the atria and the ventricles. True or False.
8. A first-degree AV block can never be wider than 0.40 seconds. True or False.
Match the following:
9. Two or more P waves blocked sequentially |
A. First-degree AV block |
10. Prolonged, constant PR intervals |
B. Mobitz I second-degree AV block |
11. Intermittently dropped QRS complexes in a strip with constant PR intervals |
C. Mobitz II second-degree AV block |
12. Noncommunicating atria and ventricles |
D. High-grade or advanced AV block |
13. Continuously prolonging PR intervals and dropped P waves |
E. Untypable second-degree AV block |
14. Two atrial complexes to one ventricular complex |
F. Third-degree AV block |
15. In some cases, second-degree AV blocks will not have any P waves at all. True or False.
16. Grouping is one of the major diagnostic features of the second-degree AV blocks. True or False.
17. The terms conduction ratios and blocks can be used interchangeably when talking about the AV blocks. True or False.
18. Which statement is incorrect about Wenckebach or Mobitz I second-degree AV block?
A. The PR interval progressively lengthens until a P wave is eventually blocked.
B. The longest PR interval is the one immediately after the dropped beat.
C. The largest incremental change in the PR interval occurs between the first and second PR intervals in a sequence.
D. The R-R intervals progressively shorten until a QRS complex is dropped.
E. The interval including the dropped P wave is less than two times the preceding P-P interval.
19. The width of the QRS complexes in Mobitz I second-degree AV block or Wenckebach can be either __________ or __________.
20. The conduction ratio in Mobitz I second-degree AV block can be:
A. 2:1
B. 3:2
C. 5:4
D. 17:16
E. All of the above
21. Mobitz II second-degree AV block is diagnosed when you have either a single or multiple nonconducted P waves in the face of a rhythm with a constant PR interval. If you have multiple blocked P waves, they are not sequentially blocked. True or False.
22. In Mobitz II second-degree AV block, the width of the QRS complexes can be _______ or ________.
23. A 2:1 ratio in a second-degree AV block can be either untypable, Mobitz I, or Mobitz II. However, you need to have at least two consecutively conducted P waves somewhere else along the strip in order to be able to diagnose Mobitz I or Mobitz II. True or False.
24. You can have capture or fusion beats in a complete or third-degree AV block. True or False.
25. The PR interval should not be constant in third-degree AV block. True or False.