January 11, 2016 - Electrocardiography II

Question 1

Axis

Answer 1

The average direction of electrical activity as it travels through the heart.

Question 2

Normal Axis

Answer 2

-30 degrees to +90 degrees

aVF and aVL

Question 3

Left Axis Deviation (LAD)

Answer 3

Positive Lead 1 and Negative Lead 2

Question 4

Right Axis Deviation (RAD)

Answer 4

Negative Lead 1 and Positive Lead aVF

Question 5

Extreme Right Axis Deviation

Answer 5

Negative Lead 1 and Negative Lead aVF

Question 6

Left Bundle Branch Block (LBBB)

Answer 6

The left bundle does not work, therefore the signal will not travel down to the left ventricle in a normal way. The right bundle however, still works well.

Because of this, there is early fast RV depolarization.

QRS is wide because it is not rapidly depolarized because the conduction occurs from myocyte to myocyte rather than through the conduction fibers.

T-waves are discordant because the normal DEpolarization of the LV is lost and the normal REpolarization of the LV is also lost.