Clin Lab - EKG Part 1

Question 1

List the 3 bipolar limb leads

Answer 1

Lead I, II, III

Question 2

List the 3 unipolar augmented leads

Answer 2

aVR, aVL, & aVF

Question 3

The limb & augmented leads combine together to show the heart’s electrical activity in the…

Answer 3

frontal plane

Question 4

Which lead is most often used to assess heart rhythm b/c it is anatomically aligned to the normal heart?

Answer 4

Lead II

Question 5

List the 6 unipolar chest (precordial) leads.

Answer 5

V1 - V6

Question 6

Which chest leads overlay the right ventricle?

Answer 6

V1 & V2

Question 7

Which leads overlay the septum of the heart?

Answer 7

V3 - V4

Question 8

Which leads overlay the left ventricle?

Answer 8

V5 & V6

Question 9

The left ventricle having a stronger contraction than the right ventricle is due to…

Answer 9

The Frank-Starling Law
- the LV has more blood in its chamber at the end of diastole; need to push the most blood out as possible

Question 10

What prevents electrical signal from going straight from the atria to the ventricles?

Answer 10

CT b/t the atria & ventricles

Question 11

NOTE

Answer 11

As depolarization occurs, an electrical field develops where some cells are (-) on the outside, some are (+)

Question 12

The separation of charges creates a…

Answer 12

dipole

Question 13

The head of the dipole points towards…

Answer 13

the (+) area –> this is the vector

Question 14

Vector pointing towards the electrode causes a…

Answer 14

up deflection

Question 15

Vector pointing away from the electrode causes a…

Answer 15

downward deflection

Question 16

Vector running parallel to the electrode causes a…

Answer 16

biphasic deflection

Question 17

How does electrical signal travel through the heart

Answer 17

R shoulder, L hip, L shoulder

Question 18

How many milliseconds long is one small box?

Answer 18

4o ms (0.04 sec)

Question 19

How many milliseconds long is one big box?

Answer 19

200 ms (0.20 sec)

Question 20

How many big boxes = 1 second?

Answer 20

5 big boxes

Question 21

How long is the QRS interval?

Answer 21

<3 small boxes (120ms)

Question 21

How long is the PR interval?

Answer 21

<1 big box (<200 ms)

Question 22

How long is the QT interval?

Answer 22

Varies by HR – meds (haloperidol, Zofran, macrolides)

QTc
440ms men
460ms women
**<2 big boxes

Question 23

NOTE

Answer 23

A nice eyeball test for QTc is that the QT interval should be less than half the preceding RR interval.

Question 24

What are 3 ways to calculate rate on an EKG?

Answer 24

- 300 – 150 – 100 - 75 --> R wave has to be on big box – regular. Find R wave that lands on big box, the line after is where the 300 is - 6 secs rule – irregular - Count on the rhythm strip

Question 25

If SA node is NOT the pacemaker – 3 possibilities

Answer 25

- Atrial area(s) other than SA node is/are pacemaker - AV node junction area is pacemaker - Ventricle area(s) is/are pacemaker

Question 26

NOTE

Answer 26

- Problems w/ the AV node or AV bundles can lead to “blocks” - Extra (accessory) pathways can change conduction

Question 27

List the types of sinus rhythm

Answer 27

- NSR - Sinus Tachy - Sinus Brady - Sinus Arrthymia - Sick Sinus Syndrome - Sinus Pause (>4 secs; >3 w/ Sx)

Question 28

List the atrial rhythms (not sinus)

Answer 28

- Afib - Aflutter - Wandering atrial Pacer - Multifocal Atrial Tachycardia - SVT - Atrial escape (ectopic escape)

Question 29

List the junctional rhythms

Answer 29

- Junctional Escape - Ventricular escape idioventricular) - Accelerated Ventricular Escape (rate >40bpm) - Accelerated Junctional (>60bpm)

Question 30

List the ventricular rhythms

Answer 30

- Vfib - Vtach - Vflutter - Torsades (multifocal VTach)

Question 31

List the types of blocks

Answer 31

- 1st degree block - 2nd degree Type I (Wenckebach) - 2nd degree Type II - 3rd degree block - Bundle Blocks

Question 32

List the accessory pathways

Answer 32

- Wolf-Parkinson White - LGL

Question 33

List the rhythms w/ wide QRS

Answer 33

Vfib Vtach Vflutter Torsades (multifocal VTach) Bundle Blocks