F - Normal ECG - Johnston

Question 1

Characteristics of the P wave

Answer 1

Atrial depolarization
Inverted in aVR
Variable

Question 2

P-R Interval

Answer 2

Time from SA node to ventricular muscle

.12 - .20 seconds

Question 3

QRS complex

Answer 3

Ventricular depolarization
.05 - .10 duration
Q waves shouldn’t be more than .03 sec in width

Question 4

What is the importance of the ST segment

Answer 4

Normally isoelectric

Can be normally elevated not more than 1mm in standard, 2 mm in chest

Question 5

T wave

Answer 5

Inverted aVR
5 mm in standard
10 mm in precordial

Question 6

How do you rule our an AV block?

Answer 6

PR Interval < .2 seconds

Question 7

How do you rule out a bundle branch block?

Answer 7

QRS < 0.1 seconds

Question 8

What are the best 2 leads to read P waves?

Answer 8

II and V1

Question 9

How much time does the dark line on ECG represent?

Answer 9

0.2 s

Question 10

How much time does the smaller boxes on ECG represent?

Answer 10

0.04 s

Question 11

How do you figure out the heart rate from on ECG?

Answer 11

Take 300 divided by the number of large boxes
OR memorize
300
150
100
75
60
50
43 ....

Question 12

How do you determine if there is a sinus rhythm?

Answer 12

P precedes QRS, 1:1

Question 13

2 conditions where P wave follows QRS

Answer 13

SVT (AV nodal re-entry tachycardia)

Junctional Rhythm

Question 14

Conditions associated with no P waves?

Answer 14

A fib, A flutter, junctional or ventricular escape rhythms, junctional tachycardia, VT

Question 15

What happens as the positive wave of depolarization within the myocyte flows toward a positive electrode?

Answer 15

There is a positive (upward) deflection recorded on ECG

Question 16

What are the 3 bipolar limb leads?

Answer 16

I, II, III

Question 17

What are the 3 augmented limb leads?

Answer 17

aVR
aVL
aVF