Axis & Chamber Enlargement (Exam #1)

Question 1

What does a Left Axis Deviation (LAD) mean?

Answer 1

Mean QRS axis between 0 degrees and -90 degrees

Question 2

What does a Right Axis Deviation (RAD) mean?

Answer 2

Mean QRS axis between +90 degrees and +180 degrees

Question 3

What type of axis is seen if Lead I and Lead aVF are both positive?

Answer 3

Normal

Question 4

What type of axis is seen if Lead I is positive and Lead aVF are negative?

Answer 4

RAD

Question 5

What type of axis is seen if Lead I is negative and Lead aVF is positive?

Answer 5

LAD

Question 6

What type of axis is seen if Lead I and Lead aVF are both negative?

Answer 6

Indeterminate (Extreme)

Question 7

What does an Equiphasic Lead mean?

Answer 7

For a given QRS complex, positive deflection = negative deflection

Question 8

If Lead I > Lead aVF, which lead is the QRS axis closer to, and what is this range?

Answer 8

Mean QRS axis is closer to Lead I

- 0 degrees to +45 degrees

Question 9

If Lead I < Lead aVF, which lead is the QRS axis closer to, and what is this range?

Answer 9

Mean QRS axis is closer to Lead aVF

- +45 degrees to +90 degrees

Question 10

What indicates a STRONG LAD?

Answer 10

R wave in aVL > R wave in I

Question 11

What indicates a STRONG RAD?

Answer 11

R wave in III > R wave in aVF

Question 12

What indicates a normal axis?

Answer 12

R wave in II > R wave in aVF

Question 13

What are the most common causes of LAD or RAD?

Answer 13

Hypertrophy (LVH with LAD and RVH with RAD)

Question 14

What involves shift in QRS axis more right, toward +90 degrees? What body type might this be seen in?

Answer 14

Vertical Heart

- Tall/thin

Question 15

What involves shift in QRS axis more left, toward 0 degrees? What body type might this be seen in (2)

Answer 15

Horizontal Heart

• Obese
• Pregnant

Question 16

What involves dilation due to stretching of walls; primarily seen with atria? What part of the EKG should be focused on?

Answer 16

Enlargement

- Evaluate P waves

Question 17

What involves thickening of walls; primarily seen with ventricles? What part of the EKG should be focused on?

Answer 17

Hypertrophy

- Evaluate QRS complex

Question 18

What is seen on the EKG with Left Atrial Enlargement (LAE)?

Answer 18

P wave with amplitude greater than 2.5 mm

Question 19

What is seen on the EKG with Right Atrial Enlargement (RAE)?

Answer 19

P wave with duration greater than 0.10 seconds

Question 20

What is seen on the EKG with Bilateral Enlargement?

Answer 20

BOTH amplitude and duration increased

Question 21

What are the two criteria for Left Atrial Enlargement (LAE) (__ OR __)?

Answer 21

• P wave >0.10 seconds
  OR
• Biphasic P wave in V1 with terminal portion duration AND depth greater than one small box (duration of 0.04+ seconds AND depth of 1+ mm)

Question 22

What are the two criteria for Right Atrial Enlargement (RAE) (__ OR __)?

Answer 22

• P wave >2.5 mm tall
  OR
• Biphasic P wave in V1 with initial > terminal portion (upward deflection > downward deflection)

Question 23

What are the three criteria for Left Ventricular Hypertrophy (LVH) (__ OR __ OR __)?

Answer 23

- Sum of deepest S in V1/V2 + tallest R wave in V5/V6 is 35+ mm
OR 
- R wave in aVL is 11+ mm
OR 
- R wave in I + S wave in III are 25+ mm

Question 24

What are the three criteria for Right Ventricular Hypertrophy (RVH) (__ OR __ OR __)?

Answer 24

- RAD greater than +90 degrees
OR
- R wave > S wave in V1
OR
- S wave > R wave in V6

Question 25

A normal R wave progression involves what?

Answer 25

Increase in size from V1 to V6