ECG - Bundle Branch Blocks

Question 1

Criteria for diagnosis of a RBBB

Answer 1

• tall R in septal leads (V1 and V2)
• Tall T in V1/V2
• Wide QRS (greater than 120 ms)
• Lateral S-waves (V4-V6)
• Some STD/TWI

Question 2

What EKG finding in the presence of a right bundle branch block is considered abnormal?

a. ST elevation
b. lateral s-waves
c. tall R-waves
d. wide QRS

Answer 2

a. ST elevation

Question 3

If a QRS points downward (such as in the case of a pacemaker or LBBB), what “normal finding” would otherwise be abnormal?

Answer 3

ST-elevation. Because of a negative R wave, some STE is expected in LBBB.

Question 4

“Easy” RBBB diagnosis

Answer 4

V1: terminal R wave
V6: slurred S
Lead I: slurred S

Question 5

“Easy” LBBB

Answer 5

V1: (-) R-wave
V6: (+) R/notched
Lead I: (+) R/notched