Bundle Branch Block Quiz Part 4

Identify the following bundle branch blocks.
1.

2.

3.

4.

5.

6.

7.

Answers

1.

Left bundle branch block

In lead I there is a broad monophasic R wave that is characteristic of a left bundle branch block.  The ST segment is opposite the initial R wave.  In V1 there are very deep, broad S waves.
2.

Left bundle branch block

In both leads I and V6 there are broad monophasic R waves.  In V6 the slurring of the terminal portion of the R wave is very pronounced.
3.

Right bundle branch block

In V1 the wide RSR pattern show this to be a right bundle branch block.
4.

Incomplete right bundle branch block

The QRS complex of V1 is less than 0.12 sec so this make the right bundle branch block incomplete.
5.

left bundle branch block

The left bundle branch block is identified in lead I by the tall, broad, notched QRS complex.
6.

Right bundle branch block

The right bundle branch block is identified in lead V1 by the wide, notched QRS complex.  The appearance of the QRS complex in lead I almost looks like that of a left bundle branch block but if you notice that there is an small initial Q wave followed by an initial positive R wave and an S wave with the terminal T wave being in the same direction as the terminal portion of the QRS complex.
7.

Right bundle branch block

In lead V1 by the wide, notched or "rabbit ear" appearance of the QRS complex makes this a right bundle branch block.