(2) Physiologic Basis for ECG and Basic ECG (Ballam)

Question 1

How many electrodes to you place on the skin surface for an EKG?

Answer 1

12 Electrodes

Question 2

What exactly does an EKG measure?

Answer 2

EXTRAcellular potential

Question 3

Describe:

EKG Tracing Deflection

Answer 3

(A) Depolarization starts, observe upward deflection

(B) All cells depolarized, NO DIFFERENCE

(C) Repolarizatio starts, observe downward deflection

(D) Once all cells are repolarized, NO DIFFERENCE

Question 4

Identify the regions for depolarization of the:

(A) Atria

(B) Ventricles

Answer 4

Question 5

What is occuring during the P wave?

Answer 5

SA nodes cause atria to depolarize from right to left

Question 6

What occurs during QRS complex?

Answer 6

Ventricles depolarize

(from right to left, interior to exterior)

Question 7

What occurs during ST segment?

Answer 7

Action potential phase 2 delays repolarization of ventricles

Question 8

What occurs during the T wave?

Answer 8

Ventricles repolarize

(left to right)

Question 9

What phase does the p wave represent in an atrial muscle AP?

Answer 9

Phase 0

Question 10

What phase does the QRS complex represent in ventricular muscle?

Answer 10

Phase 0 of AP in ventricular muscle

Question 11

Significance of the U Wave?

Answer 11

Not typically observed

Suspected to be related to unknown pathologies

Question 12

Draw:

1) An atrial AP in comparison to a ventricular AP on the same time axis
2) Atrial contraction and ventricular contraction on same time axis
3) All compared to a normal EKG rhythm

Answer 12

Question 13

What does a segment represent?

Answer 13

Duration of a single event on EKG

Question 14

What does an interval represent?

Answer 14

Duration of two or more events on EKG

Question 15

What does one heavy lined box represent VERTICALLY?

Answer 15

0.5 mV

Question 16

What does one heavy lined box represent HORIZONTALLY?

Answer 16

0.2 seconds

Question 17

Typically, how long is the QR interval?

Answer 17

0.16ms

Question 18

Typically, how long is the QT interval?

Answer 18

0.35 ms

Question 19

What is the time between light lines?

Answer 19

0.04 seconds

Question 20

Calculate the

A) times between beats

B) beats per min

Answer 20

Time between beats (5 x 0.2) + (2 x 0.04) = 1.08 sec

(60 sec/min) / 1.08 seconds = 55 beats / min

Question 21

What are the chest leads?

Answer 21

V1-V6

Question 22

Which chest leads are primarily negative?

Answer 22

V1 and V2

Question 23

Which chest lead typically demonstrates the “best” EKG?

Answer 23

V3

Question 24

Which chest leads are primarily positive?

Answer 24

V4, V5 and V6

Question 25

Which bipolar limb lead gives the most accurate full EKG? What are the degrees associated with this lead?

Answer 25

Bipolar limb lead 2 60 degrees

Question 26

Describe where you would place chest leads:

Answer 26

Question 27

What are the **inferior leads?**

Answer 27

II III AVF

Question 28

What are the **septal leads?**

Answer 28

V1 V2

Question 29

What are the **anterior leads?**

Answer 29

V2 V3 V4

Question 30

What are the **lateral leads?**

Answer 30

V4 V5 V6 I AVL

Question 31

What does a mean electrical axis deviation indicate?

Answer 31

If general direction of AP spreads to upper left = left axis deviation If general direction of AP spreads to the right = right axis deviation