Conduction Blocks

Question 1

In this type of block, impulse will be slower than normal, but not completely blocked. On ECG QRS complex looks similar to RBBB/LBBB but not as wide (>100ms).

Answer 1

Incomplete BBB

Question 2

This type of AVB has no relation between atrial and ventricular activity.

Answer 2

Third degree AVB (CHB)

Question 3

This type of AVB has PR-intervals that progressively lengthen, leading to the drop of a QRS-complex. It rarely progresses to CHB.

Answer 3

Mobitz 1 (Wenckebach)

Question 4

Name this type of block:

• LAD (>60°)
• Normal QRS duration
• Tall R waves laterally, deep S inferior

Answer 4

LAHB

Question 5

This type of AVB has prolonged PR-intervals >0.20s

Answer 5

First degree AVB

Question 6

In this type of block, the QRS does not widen, but there is an alternation in axis of the QRS complex.

Answer 6

Hemiblock

Question 7

This type of BBB has a RR complex in V6 (>120ms).

Answer 7

LBBB

Question 8

This type of hemiblock often occurs when RBBB is present.

Answer 8

LAHB

Question 9

This type of AVB has PR-intervals that are fixed, with an occasional dropped QRS. Often progresses to CHB.

Answer 9

Mobitz II

Question 10

Name this type of block:

• RAD (>120°)
• Tall R waves inferiorly
• Deep S waves laterally

Answer 10

LPHB

Question 11

Poorly tolerated CHB has a HR between what?

Answer 11

20-40

Question 12

Well-tolerated CHB has a HR between what?

Answer 12

40-60

Question 13

What is a bifascicular block?

Answer 13

RBBB w/ HB

Question 14

This type of BBB has a RsR’ complex in V1 (>120ms).

Answer 14

RBBB