ECG

Question 1

3 Basic Waves on ECG/What they relate to

Answer 1

P Wave - Atrial depol
QRS Complex - Vent depol
T Wave - Vent Repol

Question 2

Chest vs. Extremity Electrodes

Answer 2

Horizontal vs. vertical plane

Question 3

3 Bipolar Limb Leads

Answer 3

(neg -> pos)
I: R arm -> L arm
II: R arm -> L leg
III: L arm -> L leg

Question 4

3 Unipolar Limb Leads

Answer 4

Extend from heart as “-“
aVR: R arm
aVF: L leg
aVL: L arm

Question 5

QRS Naming Convention (4)

Answer 5

Q is first down if it precedes an up
R is first up
S is first down following an up
Only down is QS

Question 6

3 Stages/Directions of Normal Vent Depol, Creating QRS Complex

Answer 6

First a little bit ~160-170 deg, so slight down from I and II overriding III up, creating Q
Huge deflection about 60 deg, all 3 increase creating R
Finish off w/ ~ -45deg, so neg from III (& slightly from II) cancels out slight pos from I for S.

Question 7

Normal Hexaxial Direction and R and L Deviation

Answer 7

Normal is -30 to 90 deg, usually around 45. R is clockwise and L is counterclockwise