EKG Concepts

Question 1

What are the inferior leads, and what do they view?

Answer 1

The inferior leads are II, III, and aVF. They view the inferior wall of the left ventricle.

Question 2

What are the septal leads and what do they view?

Answer 2

Leads V1 and V2 are the septal leads. They view the septal wall of the left ventricle, and are often grouped together with the anterior leads.

Question 3

What are the anterior leads, and what do they view?

Answer 3

The anterior leads are V3 and V4. They view the anterior wall of the left ventricle.

Question 4

What are the lateral leads, and what do they view?

Answer 4

The lateral leads are I, aVL, V5, and V6. They view the lateral wall of the left ventricle.

Question 5

If the QRS complex in leads I and II is positive, what does this tell you?

Answer 5

That this is a normal QRS axis.

Question 6

What constitutes a right shift deviation?

Answer 6

If limb lead I is negative and aVF is positive, there is a right axis deviation.

Question 7

What constitutes a left shift deviation?

Answer 7

If limb lead I is positive and limb lead II is negative, there is a left axis deviation.

Question 8

What is the time interval of each little box?

Answer 8

Around 0.04 seconds.

Question 9

What is the time interval of each big box?

Answer 9

Around 0.20 seconds.

Question 10

What are the dimensions of each little box?

Answer 10

1 mm by 1 mm

Question 11

What is a normal PR interval?

Answer 11

0.12 to 0.20 seconds (3-5 small boxes). If it is more than 0.2 seconds (one big box) it’s abnormal.

Question 12

What is a normal QRS complex time interval?

Answer 12

Less than 0.12 seconds (3 small boxes)

Question 13

What is a normal QT interval?

Answer 13

Less than 0.45 seconds (over 2 big boxes).

Question 14

What does an abnormal PR interval tell you?

Answer 14

There could be a first degree heart block or some other kind of issue with the conductance system.

Question 15

What does an abnormally wide QRS complex tell you?

Answer 15

There might be a left or right bundle branch block.

Question 16

What does an abnormal QT interval tell you?

Answer 16

Myocardial infarction, ect.

Question 17

What does a depressed ST segment tell you?

Answer 17

A depressed ST segment could be caused by a NSTEMI (subendocardial MI)

Question 18

What does an elevated ST segment tell you?

Answer 18

Acute MI (STEMI, transmural MI)) or a left bundle branch block.

Question 19

What does a left axis deviation tell you?

Answer 19

Inferior MI, left ventricular hypertrophy (LVH), left bundle branch block.

Question 20

What does a right axis deviation tell you?

Answer 20

Right ventricular hypertrophy i.e. RVH (from lung pressing on the right ventricle, ect).

Question 21

What is the placement for bipolar limb lead I?

Answer 21

For lead I, the negative terminal is connected to the right arm, and the positive terminal is connected to the left arm (horizontal).

Question 22

What is the placement for bipolar limb lead II?

Answer 22

For lead II, the negative terminal is on the right arm, and the positive terminal is on the left leg.

Question 23

What is the placement for bipolar limb lead III?

Answer 23

For lead III, the negative terminal is on the left arm and the positive terminal is on the left leg.

Question 24

What does it mean for the direction towards a lead if the QRS is positive?

Answer 24

It means the axis is pointing towards the lead.

Question 25

What does it mean for the direction towards a lead if the QRS is negative?

Answer 25

It means the axis is pointing away from the lead.