Question 1

In Complete Heart Block,the PR interval is:
A)normal duration and constant.
B)constant but longer than normal.
C)normal duration but changing.
D)P waves are not related to QRS complexes.

Accepted Answer

In Complete Heart Block, there is a complete dissociation between the atria and ventricles, meaning that P waves and QRS complexes are not related. Therefore, there is no PR interval to measure.

Question 2

Third Degree Heart Block is also considered:
A)Complete Heart Block.
B)intermittent block.
C)SA node block.
D)bundle branch block.

Accepted Answer

Third Degree Heart Block is also known as Complete Heart Block, as it occurs when there is a complete blockage in the electrical conduction pathway between the atria and ventricles, leading to a complete dissociation between the two chambers of the heart.

Question 3

Wenckebach is a ________ Degree Heart Block.
A)First
B)Type I Second
C)Type II Second
D)Third

Accepted Answer

Wenckebach is another name for Mobitz Type I second-degree heart block, characterized by progressive lengthening of the PR interval until a beat is dropped.

Question 4

Second Degree Heart Block is caused by:
A)SA node failure.
B)resistance in ventricles.
C)intermittent AV conduction.
D)loss of failsafe mechanism.

Accepted Answer

Second Degree Heart Block is caused by intermittent AV conduction, meaning that there are occasional pauses or delays in the electrical signals traveling from the atria to the ventricles. This can result in skipped or irregular heartbeats. SA node failure, resistance in ventricles, and loss of failsafe mechanism are not typically related to Second Degree Heart Block.

Question 5

The type of block in which the P waves have no relationship to the QRS complexes is:
A)First Degree Heart Block.
B)Wenckebach (Type I Second Degree Heart Block).
C)Type II Second Degree Heart Block.
D)Third Degree Heart Block.

Accepted Answer

In third degree heart block, also known as complete heart block, the atria and ventricles are completely dissociated, and the P waves have no relationship to the QRS complexes. This is the most severe type of heart block and often requires a pacemaker for management.

Question 6

The most diagnostic feature of Wenckebach is:
A)there are always 2 P waves for every QRS complex.
B)the PRI is consistently regular.
C)both atrial and ventricular rates are regular.
D)the PRIs get progressively longer until one is dropped.

Accepted Answer

The most diagnostic feature of Wenckebach is the progressive lengthening of the PR intervals until a beat is dropped. Choices A and B are incorrect because Wenckebach does not involve a consistent number of P waves for every QRS complex or a consistently regular PRI. Choice C is also incorrect because the atrial rate may not necessarily be regular as it can vary depending on the underlying rhythm.

Question 7

In Third Degree Heart Block with a rate of 40-60 bpm,with a QRS of less than 0.12 sec,you should suspect that the pacemaker controlling the heart is located in the:
A)SA node.
B)atria.
C)AV junction.
D)ventricles.

Accepted Answer

Third degree heart block is characterized by a complete dissociation between the atria and ventricles. In this case, the pacemaker controlling the heart is located in the AV junction, as it is responsible for transmitting electrical signals from the atria to the ventricles. A pacemaker located in the SA node or atria would not be able to maintain the appropriate ventricular rate, and a pacemaker located in the ventricles would result in a widened QRS complex.

Question 8

In First Degree Heart Block,what additional feature must you identify?
A)Underlying rhythm
B)Pulse deficit
C)QT ratio
D)Bundle branch block

Accepted Answer

In First Degree Heart Block, the underlying rhythm must be identified in order to fully interpret the electrocardiogram (ECG) tracing. It is important to determine if the rhythm is sinus or if there are other abnormalities or arrhythmias present. Pulse deficit, QT ratio, and bundle branch block are not necessarily associated with first degree heart block.

Question 9

In Second Degree Heart Block (Type I and Type II),there is (are):
A)one P wave for every QRS complex.
B)more QRS complexes than P waves.
C)more P waves than QRS complexes.
D)no relationship between P waves and QRS complexes.

Accepted Answer

In Second Degree Heart Block, Type I (Mobitz I/Wenckebach) and Type II (Mobitz II), there are more P waves than QRS complexes because some of the atrial impulses do not lead to ventricular contraction, resulting in dropped beats.

Question 10

In Complete Heart Block,if a junctional focus is controlling the heart,the rate will be ________ beats per minute.
A)below 20
B)20-40
C)40-60
D)60-100

Accepted Answer

In Complete Heart Block, the ventricles and atria are beating independently of each other, and the ventricles are being paced by a lower pacemaker, often the AV junction. This results in a slower heart rate, typically between 40-60 beats per minute when the AV junctional focus takes over.

Question 11

In a Wenckebach,not every P wave is followed by:
A)a compensatory pause.
B)a PR interval.
C)a QRS complex.
D)another P wave.

Accepted Answer

In a Wenckebach, there is a progressive prolongation of the PR interval until eventually a QRS complex is dropped. Therefore, not every P wave is followed by a QRS complex.

Question 12

In First Degree Heart Block,conduction through the AV node is:
A)prolonged on every beat.
B)blocked completely.
C)conducted only intermittently.
D)normal on every beat.

Accepted Answer

In First Degree Heart Block, conduction through the AV node is prolonged on every beat, meaning there is a delay in the transmission of the electrical signal from the atria to the ventricles. However, the signal is still transmitted on every beat, so it is not completely blocked or conducted only intermittently. Therefore, option A is the correct answer.

Question 13

In First Degree Heart Block,the PR interval is ________ sec.
A)less than 0.12
B)0.12-0.16
C)0.16-0.20
D)greater than 0.20

Accepted Answer

In First Degree Heart Block, the PR interval is greater than 0.20 seconds. This condition is characterized by a delay in the transmission of the electrical impulse from the atria to the ventricles, which is reflected in the prolonged PR interval on an electrocardiogram (ECG).

Question 14

In First Degree Heart Block,the QRS complex should be:
A)less than 0.12 sec.
B)0.12-0.20 sec.
C)greater than 0.20 sec.
D)the same as the PRI.

Accepted Answer

In First Degree Heart Block, the PR interval may be prolonged but the QRS complex should still be less than 0.12 sec.

Question 15

In Type II Second Degree Heart Block with variable conduction,the R-R interval:
A)methodically increases.
B)randomly increases.
C)consistently decreases.
D)is irregular.

Accepted Answer

In Type II Second Degree Heart Block with variable conduction, the R-R interval is irregular, reflecting the unpredictable dropping of QRS complexes.

Question 16

If the rate is 20-40 beats per minute and the QRS measures over 0.12 sec,you should suspect that the pacemaker controlling the heart is located in the:
A)SA Node.
B)atria.
C)AV junction.
D)ventricles.

Accepted Answer

A rate of 20-40 beats per minute and a QRS duration over 0.12 seconds suggest a pacemaker located in the ventricles, such as a ventricular demand pacemaker. The SA node, atria, and AV junction typically have faster intrinsic rates and would not produce such a slow heart rate without the aid of a pacemaker.

Question 17

In Third Degree Heart Block:
A)the bundle branches are blocked.
B)the SA node and AV node are blocked.
C)some beats are conducted,while others are not.
D)the atria and ventricles are completely dissociated.

Accepted Answer

In Third Degree Heart Block (also known as complete heart block), there is a complete dissociation between the atria and ventricles. This means that the SA node and AV node are completely blocked, and there is no conduction of signals from the atria to the ventricles. As a result, the ventricles will resort to an escape rhythm, which is slower and less efficient than the regular heart rhythm. The bundle branches do not play a direct role in this condition.

Question 18

In First Degree Heart Block,the pacemaker site is usually in the:
A)AV node.
B)SA node.
C)ventricles.
D)Bundle of His.

Accepted Answer

In First Degree Heart Block, the pacemaker site is usually in the Sinoatrial (SA) node, which is the normal pacemaker of the heart. The condition is characterized by a delay in the transmission of electrical impulses from the atria to the ventricles, but the impulses still originate from the SA node.

Question 19

First Degree Heart Block is caused by:
A)a block at the SA node.
B)slow conduction through the AV node.
C)a complete block in the ventricles.
D)intermittent conduction through the ventricles.

Accepted Answer

First Degree Heart Block is caused by a delay in the conduction of electrical impulses from the atria to the ventricles, resulting in a prolonged PR interval on an ECG. This delay occurs at the level of the AV node, which is responsible for slowing down the electrical signal and coordinating the contraction of the atria and ventricles. Therefore, choice B (slow conduction through the AV node) is the correct answer.

Question 20

All of the rhythms characterized as heart blocks are caused by conduction disturbances at the:
A)SA node.
B)atrial pathways.
C)AV node.
D)Purkinje fibers.

Accepted Answer

Heart blocks are caused by conduction disturbances at the AV node, specifically in the transmission of electrical impulses from the atria to the ventricles.

Quiz 7: Heart Blocks

In Complete Heart Block,the PR interval is:

Third Degree Heart Block is also considered:

Wenckebach is a ________ Degree Heart Block.

Second Degree Heart Block is caused by:

The type of block in which the P waves have no relationship to the QRS complexes is:

The most diagnostic feature of Wenckebach is:

In Third Degree Heart Block with a rate of 40-60 bpm,with a QRS of less than 0.12 sec,you should suspect that the pacemaker controlling the heart is located in the:

In First Degree Heart Block,what additional feature must you identify?

In Second Degree Heart Block (Type I and Type II) ,there is (are) :

In Complete Heart Block,if a junctional focus is controlling the heart,the rate will be ________ beats per minute.

In a Wenckebach,not every P wave is followed by:

In First Degree Heart Block,conduction through the AV node is:

In First Degree Heart Block,the PR interval is ________ sec.

In First Degree Heart Block,the QRS complex should be:

In Type II Second Degree Heart Block with variable conduction,the R-R interval:

If the rate is 20-40 beats per minute and the QRS measures over 0.12 sec,you should suspect that the pacemaker controlling the heart is located in the:

In Third Degree Heart Block:

In First Degree Heart Block,the pacemaker site is usually in the:

First Degree Heart Block is caused by:

All of the rhythms characterized as heart blocks are caused by conduction disturbances at the: