Limb Leads

Question 1

Lead I

Answer 1

goes from R arm(-) to L arm (+) (negative to positive)

• 0º

Question 2

Lead II

Answer 2

goes from R arm (-) to L Leg (+)

negative to positive

• +60º

Question 3

Lead III

Answer 3

goes from L arm (-) to L Leg (+)

• +120º

Question 4

aV_R

Answer 4

augmented R arm positive

• views the base of the heart; the atria and the great vessels
• -150º

Question 5

aV_L

Answer 5

augmented L arm positive

• views lateral wall of left ventricle
• -30º

Question 6

aV_F

Answer 6

augmented L leg positive

• views inferior walls of left ventricle
• +90º

Question 7

Anterior Leads

Answer 7

V1-4

Question 8

Lateral Leads

Answer 8

I, aV_L, V5-6

Question 9

Inferior Leads

Answer 9

II, III, aV_F

Question 10

Left Axis Deviation

Answer 10

• mean QRS axis is between 0 and -90 degrees
  
  • pointing toward the left shoulder
• Lead I = positive
• aV_F= negative

Question 11

Right Axis Deviation

Answer 11

Mean QRS axis is between +90 and +180 degrees (pointing toward the right foot)

• Lead I = negative
• aV_F = positive