The normal ECG

Question 1

Definition of the Q wave

Answer 1

The first deflection of the QRS complex if it is downward

Question 2

Definition of R wave

Answer 2

The first upward deflection

Question 3

Definition of R-prime (R’)

Answer 3

The second upward deflection (if present)

Question 4

Definiton of S wave

Answer 4

First downward deflection following an upward deflection

Question 5

Definition of QS wave

Answer 5

If the entire QRS is one downward deflection

Question 6

In which Leads is Q wave normal?

What is the normal amplitude of the Q wave?

Answer 6

Lateral leads (AvL, I, V5, V6) - represents septal depolarization

Normal amplitude should be max 0.1 mV

Question 7

What is the difference between segments and intervals?

Answer 7

Interval = wave + segment

Question 8

Which leads are the inferior leads?

Answer 8

Lead II, III, AvF (60, 120, 90 degrees)

Question 9

Which leads are the lateral leads?

Answer 9

Lead I, AvL(0, -30), V5, V6

Question 10

Which lead is the right sided?

Answer 10

AvR (-150) V1

Question 11

Which leads are anterior?

Answer 11

V2, V3, V4

Question 12

What is the normal duration of the PR interval?

Answer 12

0.12 - 0.2 s

Question 13

What is R wave progression?

Answer 13

Progressivly increasing R amplitude from V1 to V5

V6 is normally a little smaller than V5

Question 14

How long is the normal QRS interval?

Answer 14

0.06s - 0.1 s

Question 15

In which leads should the T wave be positive?

Answer 15

It is typically positive in leads with a tall R wave

Question 16

What is the typical length of the QT interval?

Answer 16

It normally composes 40% of the cardiac cycle.

Question 17

What is the normal QRS amplitude?

Answer 17

10mV in chest leads

5mV in limb leads

Question 18

How can you see if the rhytm is from the sinus node?

Answer 18

positive QRS in leads I and II, negative in AvR

Question 19

What is the normal heart axis?

Answer 19

90 to -30 degrees (pos QRS in lead I, II)

Question 20

What is the normal duration and amplitude of the P wave?

Answer 20

less than 0.12s and max 2,5mm

Question 21

What is the easiest way to calculate heart rate on ECG?

Answer 21

300 divided by number of large squares pr cycle

or

1500 divided by number of small squares pc cycle