Conduction Blocks Flashcards
What is a conduction block?
Any obstruction or delay of the normal pathways of electrical conduction.
3 types of Conduction Blocks:
Sinus node block
AV block
Bundle branch block
What type of block:
Sinus node fires normally, but wave of depolarization is blocked and not transmitted to atrial tissue.
Sinus node block
What type of block:
Any conduction block between the sinus node and Purkinje fibers (including AV node & His bundle).
AV block
What type of block:
Conduction block in one or both of the ventricular bundle branches.
Bundle branch block
What is a type of bundle branch block where only part of one of the bundle branches is blocked?
Fascicular block
What are the 3 types of AV blocks?
First Degree
Second Degree
Third Degree
What type of block:
1º AV Block
What type of block:
2º AV Block Mobitz II
What type of AV block is characterized by a suddenly dropped QRS?
2º AV Block Mobitz II
What type of block:
3º AV Block
What type of block:
1º AV Block
What type of block:
2º AV Block
What type of block:
2º AV Block Mobitz II
What type of block:
3º AV Block
What are the steps to identify a RBBB? (2)
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
What type of block:
RBBB
Notice 2 R waves in V1 and V2.
Notice “slurred S” wave in V5, V6, and I.
What are the steps to identify a LBBB? (2)
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
What type of block:
LBBB
What type of block:

RBBB
What type of block:

LBBB
What type of block:

RBBB
What major effect does a hemiblock have on the EKG?
axis deviation
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.
Left Anterior Hemiblock


