Deck 7: Atrioventricular Blocks

Question 1

An ECG rhythm strip shows a regular ventricular rhythm at a rate of 30 beats/min, more P waves than QRS complexes (the P waves occur regularly), a variable PR interval, and a QRS duration of 0.14 second. This rhythm is _____.

A) 2:1 AV block
B) third-degree AV block
C) second-degree AV block type I
D) second-degree AV block type II

Answer 1

B
With a third-degree block, the ventricular and atrial rhythms are regular; however, AV dissociation is present. The ventricular rate is determined by the origin of the escape rhythm. Based on the description provided (i.e., a QRS duration of 0.14 second and a ventricular rate of 30 beats/min), the escape pacemaker is probably ventricular in origin. P waves are normal in size and shape, but some P waves are not followed by a QRS complex. There is no true PR interval because the atria and the ventricles beat independently of each other. The QRS may be narrow or wide, depending on the location of the escape pacemaker and the condition of the intraventricular conduction system.

Question 2

Complete the following ECG criteria for 2:1 AV block:

Answer 2

Question 3

Complete the following ECG criteria for first-degree AV block:

Answer 3

Question 4

The PR interval of a first-degree AV block _____.

A) is constant and less than 0.12 second in duration
B) is constant and more than 0.20 second in duration
C) is generally progressive until a P wave appears without a QRS complex
D) gradually decreases in duration until a P wave appears without a QRS complex

Question 5

Second-degree AV block type II is characterized by _____ intervals.

A) irregular P to P
B) irregular R to R
C) regular P to P intervals and regular R to R
D) irregular P to P intervals and irregular R to R

Question 6

Complete the following ECG criteria for second-degree AV block type II:

Question 7

A _____ bundle branch block produces a QS pattern in lead V?.

Question 8

Complete the following ECG criteria for second-degree AV block type I:

Question 9

In 2:1 AV block, _____.

A) the atrial rhythm (P-P interval) is regular
B) the ventricular rhythm (R-R interval) is irregular
C) the PR interval lengthens until a P wave appears with no QRS complex
D) there is no PR interval because the atria and ventricles beat independently of each other

Question 10

In second-degree and third-degree AV blocks, _____.

A) P waves occur regularly
B) every other P wave is dropped
C) P waves are periodically dropped
D) there are more QRS complexes than P waves

Question 11

In second-degree AV block type I, the PR interval _____.

A) shortens
B) is absent
C) is inconstant
D) remains constant

Question 12

Most of the bundle branch tissue is supplied by the _____ coronary artery.

A) right
B) left

Question 13

Identify the following rhythm: _________________________

Question 14

In third-degree AV block, _____.

A) the atrial rhythm (P-P interval) is irregular
B) the ventricular rhythm (R-R interval) is irregular
C) there is no PR interval because the atria and ventricles beat independently of each other
D) the PR interval after a nonconducted P wave is shorter than the interval preceding the nonconducted beat

Question 15

A 2:1 AV block is characterized by _____ intervals.

A) irregular P to P
B) irregular R to R
C) regular P to P intervals and regular R to R
D) irregular P to P intervals and regular R to R

Question 16

Indicate the ECG criteria for the following dysrhythmias:

Question 17

A _____ bundle branch block produces a RSR pattern in lead V?.

Question 18

Second-degree AV block type I is characterized by _____ intervals.

A) irregular P to P
B) regular R to R
C) regular P to P intervals and irregular R to R
D) irregular P to P intervals and irregular R to R

Question 19

Complete the following ECG criteria for third-degree AV block:

Question 20

In 2:1 AV block, the PR interval _____.

A) shortens
B) lengthens
C) is absent
D) remains constant

Question 21

Identify the following rhythm: _________________________

Question 22

Identify the following rhythm: _________________________

Question 23

Identify the following rhythm: _________________________

Question 24

Identify the following rhythm: _________________________

Question 25

Identify the following rhythm: _________________________

Question 26

Identify the following rhythm: _________________________

Question 27

Identify the following rhythm: _________________________

Question 28

Identify the following rhythm: _________________________

Question 29

Identify the following rhythm: _________________________

Question 30

Identify the following rhythm: _________________________

Question 31

Identify the following rhythm: _________________________

Question 32

Identify the following rhythm: _________________________

Question 33

Identify the following rhythm: _________________________

Question 34

Identify the following rhythm: _________________________

Question 35

Identify the following rhythm: _________________________

Question 36

Identify the following rhythm: _________________________

Question 37

Identify the following rhythm: _________________________

Question 38

Identify the following rhythm: _________________________

Question 39

Identify the following rhythm: _________________________

Question 40

Identify the following rhythm: _________________________

Question 41

The QRS complex associated with a third-degree AV block is always wide.

Question 42

Indicate the ECG criteria for the following dysrhythmias.

Question 43

Indicate the ECG criteria for the following dysrhythmias.

Question 44

Identify the following rhythm: _________________________

Question 45

The ventricular rhythm is regular in second-degree AV block type I.

Question 46

Identify the following rhythm: _________________________

Question 47

Identify the following rhythm: _________________________

Question 48

Identify the following rhythm: _________________________