Deck 15: Origin and Clinical Aspects of AV Heart Blocks

Question 1

PR intervals of greater than 0.20 are indicative of:

A) a pacemaker site which is either in or close to the AV junction.
B) an intermittent blocking of the impulse as it passes through the AV node.
C) a delay in conduction of the impulse between the SA node and the ventricles.
D) an increased rate of impulse discharge from the SA node.

Answer 1

a delay in conduction of the impulse between the SA node and the ventricles.

Question 2

Which of the following is a delay and not a true AV heart block?

A) Wenckebach
B) 2nd- degree AV heart block, Type II
C) 3rd- degree AV block
D) 1st-degree AV block

Answer 2

1st-degree AV block

Question 3

With 1st-degree AV heart block:

A) there are more P waves than QRS complexes
B) the PR interval is constant
C) the AV node grows more and more tired with each impulse it carries through from the atria to the ventricles
D) the PR interval is between 0.12 and 0.20 seconds in duration

Answer 3

the PR interval is constant

Question 4

1st-degree AV heart block:

A) is of little or no clinical significance
B) causes decreased cardiac output
C) typically progresses to higher degree block
D) must be promptly treated with anti-dysrhythmic agents

Question 5

The most obvious characteristic of 1st-degree AV heart block:

A) is a fast heart rate.
B) are PR intervals greater than 0.20 seconds in duration and constant..
C) is an irregular rhythm that seems to repeat itself over and over again.
D) Are wide, bizarre-looking QRS complexes.

Question 6

Which of the following originates from the SA node?

A) Idioventricular rhythm.
B) Wandering atrial pacemaker.
C) Premature junctional complex.
D) Second degree AV block, Type I.

Question 7

Which of the following dysrhythmias has more P waves than QRS complexes?

A) 1st- degree AV heart block.
B) 2nd - degree AV block, Type I.
C) junctional escape rhythm.
D) sinus dysrhythmia.

Question 8

Characteristics of 2nd- degree AV heart block, Type I include:

A) QRS complexes which are wide and biphasic.
B) a rate of between 60 and 100 beats per minute.
C) an inverted P wave which follows each QRS complex.
D) PR intervals which become progressively longer.

Question 9

Which of the following dysrhythmias has a "patterned irregular rhythm?"

A) sinus rhythm with occasional PVCs
B) 3rd degree AV heart block.
C) Wenckebach.
D) 2nd-degree AV heart block, Type II

Question 10

In which of the following types of AV heart block does the PR interval remain constant?

A) 3rd- degree AV heart block.
B) Wenckebach.
C) 2nd-degree AV heart block, Type II
D) b & c

Question 11

Your patient is a 70-year-old male who passed out at church. He is now awake but seems confused, has a respiratory rate of 20 breaths per minute, a blood pressure of 90/60 and cool, moist skin. You attach the ECG monitor to reveal what appears to be a slow heart rate. A closer examination of the ECG shows there are two P waves preceding each QRS complex and the PR interval for the conducted beats remains constant. This dysrhythmia is:

A) 2nd - degree AV block, Type II
B) sinus bradycardia
C) 3rd - degree AV heart block
D) Wenckebach

Question 12

2nd-degree AV heart block, Type II:

A) is a complete block at the level of the bundle of His
B) is more common and serious than Type I
C) eventually progresses to complete AV heart block.
D) is considered malignant in the emergency setting where it is symptomatic.

Question 13

Characteristics of 2nd- degree AV heart block, Type II include:

A) a patterned irregular rhythm
B) a rate of greater than 100 beats per minute
C) narrow QRS complexes
D) PR intervals that vary in duration

Question 14

In _____________ the number of P waves for each QRS complex may be fixed or it may vary.

A) 2nd - degree AV heart block, Type II
B) 1st - degree AV heart block
C) 2nd - degree AV block, Type I
D) idioventricular rhythm

Question 15

3rd-degree AV heart block is:

A) an intermittent block at the level of the bundle of His.
B) a complete block of impulse conduction at or below the AV node.
C) a delay in conduction of the impulse through the AV node.
D) a block in impulse conduction through one or both of the bundle branches.

Question 16

With 3rd-degree AV heart block the:

A) AV node serves as the pacemaker for the atria, typically maintaining a regular rate of 60 to 100 beats per minute.
B) impulses from the atria reach the ventricles through an accessory pathway which is situated between the atria and ventricles
C) P waves and QRS complexes occur rhythmically and are related to each other.
D) pacemaker for the ventricles arises as an escape rhythm from the AV junction or from the ventricles.

Question 17

Characteristics of 3rd-degree AV heart block include:

A) the presence of inverted P waves that precede each QRS complex.
B) PR intervals that get progressively longer in duration.
C) a ventricular rate of between 60 and 100 beats per minute.
D) P waves that appear normal and seem to march right through the QRS complexes.

Question 18

2nd-degree AV heart block, Type I, is an intermittent block at the level of the AV node.

Question 19

The feature that stands out in 2nd-degree AV heart block, Type II, is the presence of more P waves than QRS complexes.

Question 20

Most occurrences of 3rd-degree AV heart block are well tolerated as long as the escape rhythm is fast enough to generate a sufficient cardiac output to maintain adequate perfusion.