Conduction Blocks

Question 1

What is a conduction block?

Answer 1

Any obstruction or delay of the normal pathways of electrical conduction.

Question 2

3 types of Conduction Blocks:

Answer 2

Sinus node block

AV block

Bundle branch block

Question 3

What type of block:

Sinus node fires normally, but wave of depolarization is blocked and not transmitted to atrial tissue.

Answer 3

Sinus node block

Question 4

What type of block:

Any conduction block between the sinus node and Purkinje fibers (including AV node & His bundle).

Answer 4

AV block

Question 5

What type of block:

Conduction block in one or both of the ventricular bundle branches.

Answer 5

Bundle branch block

Question 6

What is a type of bundle branch block where only part of one of the bundle branches is blocked?

Answer 6

Fascicular block

Question 7

What are the 3 types of AV blocks?

Answer 7

First Degree
Second Degree
Third Degree

Question 8

What type of block:

Answer 8

1º AV Block

Question 9

What type of block:

Answer 9

2º AV Block Mobitz II

Question 10

What type of AV block is characterized by a suddenly dropped QRS?

Answer 10

2º AV Block Mobitz II

Question 11

What type of block:

Answer 11

3º AV Block

Question 12

What type of block:

Answer 12

1º AV Block

Question 13

What type of block:

Answer 13

2º AV Block

Question 14

What type of block:

Answer 14

2º AV Block Mobitz II

Question 15

What type of block:

Answer 15

3º AV Block

Question 16

What are the steps to identify a RBBB? (2)

Answer 16

Look in V1 and V2 for a R₁R¹ wave (basically 2 R waves)

Look in V5, V6, and Lead I for a “slurred S” wave

Question 17

What type of block:

Answer 17

RBBB

Notice 2 R waves in V1 and V2.

Notice “slurred S” wave in V5, V6, and I.

Question 18

What are the steps to identify a LBBB? (2)

Answer 18

Look in V5, V6, or Lead I for a blunted positive QRS and t-wave is inverted

Look in V1-V3 for a predominantly negative QRS

Question 19

What type of block:

Answer 19

LBBB

Question 20

What type of block:

Answer 20

RBBB

Question 21

What type of block:

Answer 21

LBBB

Question 22

What type of block:

Answer 22

RBBB

Question 23

What major effect does a hemiblock have on the EKG?

Answer 23

axis deviation

Question 24

What type of block:

Conduction down the left anterior fascicle is blocked and current rushes down the left posterior fascicle to the inferior surface of the heart.

Depolarization goes from inferior to superior and right to left in direction.

Answer 24

Left Anterior Hemiblock

Question 25

What type of block:

Tall R wave in left lateral leads

Deep S waves inferiorly

Answer 25

Left Anterior Hemiblock

Question 26

What type of block:

Answer 26

Left Anterior Hemiblock

Question 27

What type of block:

All of the current rushes down the left anterior fascicle and ventricle myocardial depolarization ensues superior to inferior and left to right in direction.

The axis of depolarization is down and to the right (RAD), tall R waves in inferior leads and deep S waves in left lateral leads.

Answer 27

Left Posterior Hemiblock

Question 28

What type of block:

Answer 28

Left Posterior Hemiblock