EKG Theory

Question 1

Measures potential differences in the electrical energy traveling across the surface of the body that is released by muscle tissue during depolarization. This causes changes in electrical potential across the surface of the skin

Records data on graph paper at 25 mm/sec (u use 2 set this speed on the LP9 model)

Many diseases of the heart result in specific changes 2 signwave output.

Answer 1

EKG

Question 2

Small box = 1 mm x 1 mm

Vertical axis represents measured voltage at 0.1 mV/small box
Horizontal axis represents time elapsed at 40 msec (0.04)

Speed is set at 25 mm/sec but can b adjusted w/permission

Standard calibration box is 10 mm tall by 5 mm wide

Standard gain is 10 mm/1 mV

Answer 2

EKG grid paper

Question 3

The physiologist that discovered the electrical charges on the skin’s surface and recorded the first tracing of electrical activity of the heart

Answer 3

Einthoven

Question 4

Points represent locations of the standard EKG leads centered on the chest creating an imaginary triangle

Lead I: right arm(-) 2 left arm(+)
Lead II: right arm(-) 2 left leg(+)
Lead III: left arm(-) 2 left leg(+)

Answer 4

Einthovan’s triangle

pic in EKG photo file

Question 5

Imaginary triangle created by the 3 limb leads:

• right and left arm
• left leg only(right leg is grounded)

Serves as a reference point for 6 of the 12 leads

Includes unipolar and bipolar leads

Improper placement of limb leads creates an incorrect reference point

Answer 5

Wilson’s Central Terminal

WCT