1. The pacemakers responsible for the PACs are found in the _____.
2. PACs are usually clinically significant and require immediate attention. True or False.
3. The basic pacemaking rate of atrial tissue is usually set at:
A. 70–80 BPM
B. 65–70 BPM
C. 60–65 BPM
D. 55–60 BPM
E. 50–55 BPM
4. After a PAC, the sinus node takes over as the pacemaker. However, the rhythm may be reset at a different rate. True or False.
5. The P wave is an electrocardiographic representation of atrial depolarization. Each myocyte is responsible for its own small vector. When these vectors are added together, they form the ___________.
6. A P-wave vector heading toward the AV node (inferiorly) makes the P waves appear ________ in leads II, III, and aVF.
7. A P-wave vector heading away from the AV node (superiorly) makes the P waves appear ________ in leads II, III, and aVF.
8. A premature junctional contraction with retrograde conduction to the atria will give you upright P waves in lead II. True or False.
9. Whenever you see inverted P waves in lead II, it should make you think of ectopic pacemakers in either the atria, AV node, or the ventricles. True or False.
10. In a PAC, the PR intervals:
A. Are shorter than expected
B. Are longer than expected
C. Can be either shorter or longer than expected
11. The longer the distance to the AV node that the depolarization wave has to travel, the longer the PR interval. True or False.
12. The pacemaking function of any cardiac tissue is dependent on the rate of phase 4 depolarization that it intrinsically possesses. True or False.
13. A PAC causes the sinus node to _____ its pacemaking rate by depolarizing the tissue early.
14. A pause that is an exact multiple of the P-P interval and is associated with premature complexes is known as a:
A. Compensatory pause
B. Competitive pause
C. Noncompensatory pause
D. Noncompetitive pause
E. None of the above
15. A pause that is not an exact multiple of the P-P interval and is associated with premature complexes is known as a:
A. Compensatory pause
B. Competitive pause
C. Noncompensatory pause
D. Noncompetitive pause
E. None of the above
16. PACs are usually associated with noncompensatory pauses because the SA node is reset by the premature atrial depolarization wave. True or False.
17. Aberrantly conducted PACs generally have QRS complexes that show:
A. Left bundle branch block pattern
B. Right bundle branch block pattern
C. Intraventricular conduction delay
D. None of the above
18. The P waves in a PAC will always be clearly identifiable. True or False.
19. The T waves and P waves of adjacent complexes sometimes appear together, forming unusual shapes or actually fusing. True or False.
20. Sometimes the conduction to the ventricles from a PAC may actually be blocked. This makes the P wave of the PAC visible, but the QRS and T waves are not. When this occurs, it is known as a blocked PAC. True or False.