RBBB

Question 1

What is bundle branch block?

Answer 1

Blockage in either the left or right bundle branch leading to altered ventricular depolarization

Impulses from the atria or AV node conduct down both left and right bundle branches to the Purkinje Fibers.

Question 2

What are the ECG characteristics of Bundle Branch Block?

Answer 2

Wide QRS complex (>0.12s) and bizarre morphology

P waves assist in differentiation from ventricular ectopic beats.

Question 3

What is Right Bundle Branch Block (RBBB)?

Answer 3

Conduction occurs first down the left bundle, then depolarizes the right ventricle slowly

This results in a reverse depolarization direction.

Question 4

What are the ECG characteristics of RBBB?

Answer 4

QRS complex ≥ 0.12 seconds, RsR’ pattern in V1 & V2, taller second R or R’, slurred S wave in Lead 1 & V6

Incomplete RBBB occurs when QRS is < 0.12 seconds.

Question 5

What are the common causes of Right Bundle Branch Block?

Answer 5

• Congenital heart disease
• Ischemic heart disease
• Cardiomyopathy
• Right heart strain

RBBB can also be a normal variant in healthy individuals.

Question 6

What is Bifascicular Block?

Answer 6

Combination of RBBB and a hemiblock (LAH or LPH)

LAH stands for left anterior hemiblock; LPH stands for left posterior hemiblock.

Question 7

What defines Trifascicular Block?

Answer 7

Combination of RBBB, a hemiblock (LAH or LPH), and a 1st degree AV block

1st degree AV block indicates a delay in conduction through the AV node.

Question 8

What is the QRS width in Bundle Branch Block?

Answer 8

> 0.12 seconds

Question 9

In which leads are Bunny Ears visible in RBBB?

Answer 9

Leads V1 & V2

Question 10

What is required for the identification of Trifascicular Block?

Answer 10

RBBB, hemiblock (LAHB or LPHB), and 1st degree AVB

Question 11

Fill in the blank: The QRS complex in RBBB is _______.

Answer 11

≥ 0.12 seconds

Question 12

True or False: Right Bundle Branch Block can be a normal variant in healthy individuals.

Answer 12

True