Calculate axis

Question 1

What does the Electrical Axis represent?

Answer 1

The summation of all cardiac vectors

This indicates the overall direction of the heart’s electrical activity during depolarization.

Question 2

What does the Electrical Axis indicate during ventricular activation?

Answer 2

The direction of the heart’s depolarization wave front

Question 3

How is the Electrical Axis related to the heart?

Answer 3

It is related to the location of the heart’s major muscle bulk

Question 4

How is the Electrical Axis calculated?

Answer 4

By examining R wave potentials of limb leads

Question 5

What indicates the polarity of the QRS complex?

Answer 5

If it is predominantly above (+) or below (-) baseline

Question 6

What is the classification for Lead I (+) and Lead II (+)?

Answer 6

Normal Axis

Question 7

What classification results from Lead I (+) and Lead II (-)?

Answer 7

Left Axis Deviation (LAD)

Question 8

What does Lead I (-) and Lead II (+) indicate?

Answer 8

Right Axis Deviation (RAD)

Question 9

What is indicated by both Lead I and Lead II being negative?

Answer 9

Extreme RAD or Indeterminate Axis

Question 10

What is the normal axis range in degrees?

Answer 10

+90 to -30 degrees

Question 11

What is the Hexaxial Reference Circle used for?

Answer 11

To identify the most isoelectric limb lead directing toward the quadrant

Question 12

How do you determine the axis from the isoelectric lead?

Answer 12

By using perpendicular spokes from the isoelectric lead

Question 13

What is the first step in Axis Calculation?

Answer 13

Find the Quadrant

Question 14

What should you do if multiple isoelectric leads are present?

Answer 14

Choose the lead with the lowest voltage

Question 15

What does visualizing on the Reference Circle involve?

Answer 15

Creating a line from one degree to another (e.g., -120 degrees to +60 degrees)

Question 16

What shape is formed to represent the quadrant when calculating the axis?

Answer 16

A ‘T’ pointing into the quadrant

Question 17

What does assessing the Net Voltage involve?

Answer 17

Determining if QRS in isoelectric lead has more positive or negative net voltage

Question 18

What adjustment is made based on net voltage?

Answer 18

Shift axis based on net voltage (e.g., move 10 degrees for one small positive box)

Question 19

What is an example adjustment for a negative net voltage of 2 mm?

Answer 19

Requires a 20-degree shift away from positive pole

Question 20

What is the final QRS Axis for an example of LAD?

Answer 20

-50 degrees

Question 21

What is the result of Lead I positive and Lead II negative?

Answer 21

Left Axis Deviation

Question 22

What is indicated when both Lead I and Lead II are negative?

Answer 22

Extreme Right Axis or Indeterminate Axis

Question 23

What is the classification when both Lead I and Lead II are positive?

Answer 23

Normal Axis

Question 24

What are the normal axis values?

Answer 24

+90 to -30 degrees

Question 25

What does the electrical axis represent?

Answer 25

The summation of all cardiac vectors

Question 26

What does the electrical axis indicate?

Answer 26

The direction of the heart’s depolarization wave front during ventricular activation

Question 27

How is the electrical axis calculated?

Answer 27

By examining R wave potentials of limb leads

Question 28

What are the four quadrants identified using Lead I and Lead II?

Answer 28

* Normal Axis * Left Axis Deviation (LAD) * Right Axis Deviation (RAD) * Extreme RAD or Indeterminate Axis

Question 29

What is the normal axis range in degrees?

Answer 29

+90 to -30 degrees

Question 30

What is a hexaxial reference circle used for?

Answer 30

To visualize the electrical axis and identify quadrants

Question 31

What does the polarity of the QRS complex indicate?

Answer 31

Whether it is predominantly above (+) or below (-) the baseline

Question 32

What is the first step in axis calculation?

Answer 32

Find the Quadrant using Leads I and II

Question 33

What is meant by the most isoelectric lead?

Answer 33

The lead with the lowest voltage among the limb leads

Question 34

How do you create a perpendicular line on the hexaxial reference circle?

Answer 34

Form a 'T' pointing into the identified quadrant

Question 35

What is assessed when determining axis adjustment?

Answer 35

If the QRS in the isoelectric lead has more positive or negative net voltage

Question 36

What adjustment is made for a negative net voltage of 2 mm?

Answer 36

A 20-degree shift away from the positive pole

Question 37

What is the final QRS axis example for Left Axis Deviation?

Answer 37

50 degrees

Question 38

True or False: Lead I positive and Lead II negative indicates Right Axis Deviation.

Answer 38

False

Question 39

Fill in the blank: The electrical axis is related to the location of the heart's major _______.

Answer 39

muscle bulk

Question 40

What do Lead I and Lead II both being negative indicate?

Answer 40

Extreme Right Axis or Indeterminate Axis

Question 41

What do Lead I and Lead II both being positive indicate?

Answer 41

Normal Axis