ECG Part I

Question 1

The P Wave indicates ____ depolarization before atrial contraction

Answer 1

atria

Question 2

The QRS complex indicates when the ____ depolarize before contraction

Answer 2

ventricles

Question 3

The T Wave indicates when the ____ recover from the state of depolarization

Answer 3

ventricles

Question 4

Flow of Electrical Currents moves from the ___ node to the __ node to the ____

Answer 4

SA –> AV –> Septum

Question 5

Where is Lead I placed?

Answer 5

on the left arm

Question 6

Where is Lead II placed?

Answer 6

on the right arm

Question 7

Where is Lead III placed?

Answer 7

on the left foot

Question 8

What do the 3 leads create?

Answer 8

Einthoven’s Triangle

Question 9

Lead __ Potential + Lead __ Potential = Lead __ Potential

Answer 9

1 + 3 = 2

Question 10

Where do you place V1?

Answer 10

4th intercostal space on the RIGHT side

Question 11

Where do you place V2?

Answer 11

4th intercostal space on the LEFT side

Question 12

Where do you place V6?

Answer 12

Mid-axillary line/armpit space in the 5th intercostal space on the LEFT side

Question 13

AVL creates a ____ deflection, AVF creates a ___ deflection (down & left) and AVR creates a large ___ deflection due to a ___ vector vantage point

Answer 13

positive
positive
negative
positive

Question 14

When examining an ECG, what are the main components to identify? (4)

Answer 14

1. Rhythm
2. PR interval
3. QRS Axis & Morphology
4. ST Segment depression & elevation

Question 15

Each tiny square on an ECG indicates how many seconds?

Answer 15

0.4s

Question 16

If the R-R interval is 1 second, what is the HR?

Answer 16

60bpm

Question 17

The normal R-R interval is 0.83s which is a HR of 60/0.83s or ___bpm

Answer 17

72bpm

Question 18

What are the 3 methods of determining HR?

Answer 18

1. 1500 boxes = 60s; count the number of small boxes and divide from 1500 (ex: 23 boxes: 1500/23 = 65bpm)
2. Countdown Method (1 large box = 300bpm, 2” = 150bpm, 3” = 75bpm, 4” = 60bpm, 5” = 50bpm and 6” = 43bpm)
3. 10s Intervals = count number of R complexes and multiply by 6 –> this method accounts for the irregularity in the heart beat (more accurate)

Question 19

Describe the normal pathway for cardiac conduction

1. __ –> 2. __ –> 3. __ –> 4. ___ (split A or B)

A split: 5.__ –> 6.__
B split: 5. __ –> C, D, E splits

C split: 6.___
D split: 6. ___ –> 7. ____
E split: 6. ___ –> 7. ____

Answer 19

1. SA node
2. Atria
3. AV node
4. BUNDLE OF HIS

A split: Bundle of His –> Right Bundle Branch –> RIGHT VENTRICLE!

B split: Bundle of His –> Left Bundle Branch –> C, D, E

C split: Left Bundle Branch –> Septum
D split: Left Bundle Branch –> Left Posterior Fascicle –> LEFT VENTRICLE!
E split: Left Bundle Branch –> Left Anterior Fascicle –> LEFT VENTRICLE!

Question 20

If electricity goes TOWARD a lead, it creates a ____ deflection whereas if it goes AWAY from a lead it creates a _____ deflection

Answer 20

positive; negative

Question 21

Only what kind of leads will tell you cardiac axis?

Answer 21

limb leads

Question 22

Bipolar Leads are __, ___, ___

Augmented Unipolar Leads are ___, ___, ___

Answer 22

I, II, III

aVR, aVL and aVF

Question 23

What are the 3 methods for determining the cardiac axis?

Answer 23

1. Determining Quadrant
2. Getting approx. number on hexaxial reference system
3. Getting exact number on hexaxial reference system

Question 24

What is the Hexaxial reference system? What plane is it in?

Answer 24

diagram that is used to determine the heart’s electrical axis in the frontal plane.

Diagram showing how the polarity of the QRS complex in leads I, II, and III can be used to estimate the heart’s electrical axis in the frontal plane.

Question 25

5 steps for the Hexaxial method:

1. Determine the ____ lead
2. Find the lead on the ____
3. Find the _____ lead
4. Determine if it is ___ or ___
5. Find your ___

Answer 25

equiphasic
diagram
perpendicular
positive/negative
axis

Question 26

Axis Deviations:

1. -90 to 180: ____
2. 90 to 180: ____
3. -30 to -90: ____

Answer 26

ERAD
Right Axis Deviation
Pathological Left Axis Deviation

Question 27

Transition of R wave:

1. Early Transition: ____ rotation
2. Late Transition: ____ rotation

Answer 27

counterclockwise

clockwise

Question 28

Bundle Branch Blocks (BBB) include a QRS complex that is generally ____ (>120ms), P waves with a ____ rhythm or no P waves at all with a ____ rhythm and ___ elevation being normal with a LBBB

Answer 28

wide
supraventricular
ventricular
ST

Question 29

RBBB is a conduction delay thru the right ventricle:

1. ___ septal depolarization
2. ___ left ventricular depolarization
3. ____ right ventricular depolarization
4. ____ R waves OR __ QRS phenomen

Answer 29

normal
normal
delayed
double; 2

Question 30

In RBBB, the QRS morphology is altered:

1. V1 and V2 show an ___ R wave progression, “_____” or RSR, and a ___ QRS complex
2. Slurred __ wave in the ___ leads (I, aVL, V5 & V6)

Answer 30

Early
Rabbit Ears
Wide

S
Lateral

Question 31

LBBB is a conduction delay thru the left ventricle:

1. Septum will depolarize ____ from right to left
2. ____ right ventricular depolarization
3. ____ left ventricular depolarization
4. ____ R waves or ___ QRS phenomenon that is not always as easily seen

Answer 31

abnormally
normally
delayed
double; wide

Question 32

In LBBB, the QRS morphology is altered:

1. V1 and V2 show an ___ and ___ RS pattern, a wide and upright __ pattern or RSR prime pattern in lateral leads (__________)
2. NO _ wave in lateral leads (___)

Answer 32

deep; wide
RS
1, aVL, V5, V6

q
1, aVL, V5, V6

Question 33

Take-aways from ECG I (6)

Answer 33

1. Depolarization and Repolarization of ECG signal
2. Identifying normal wave intervals (P-R, QRS complex, Q-T, etc)
3. Determine HR from ECG
4. Vectors of the conduction signal determine if ECG lead is positive or negative
5. Bipolar leads and unipolar leads determine the cardiac axis
6. Understanding R-wave progression can provide insite on left/right ventricular pathologies