Lecture 17: Normal ECG Part I and II

Question 1

Label these on an EKG
PR segment
PR interval
ST segment
QRS interval
QT interval 
Equivalent time and voltage between large and small boxes

Answer 1

Ok

Question 2

What are the characteristics of a normal P wave?

Answer 2

Upright in 1,2, V4-6, aVF
Inverted in aVR
Variable in the rest

Question 3

What are the characteristics of a normal P-R interval?

Answer 3

Length should be 0.12 - 0.2 s

Question 4

What are the characteristics of a normal QRS?

Answer 4

Length 0.5 - 0.10 s

Question 5

What are the characteristics of normal Q waves?

Answer 5

<0.03s

Question 6

What characterizes a narrow Q wave? What leads are these read as normal?

Answer 6

1-2 mm

1, aVL, aVF, V5-6

Question 7

What are the characteristics of a normal ST segment?

Answer 7

Compare to PR segment baseline, shape

Question 8

How much can ST segment be elevated in standard leads?

How about precordial leads?

Answer 8

<1 mm

<2mm

Question 9

An ST depression >1/2 mm means?

An ST prominent ST elevation means?

Answer 9

• subendocardial injury/ischemia

- epicardial injury/ischemia

Question 10

What are the characteristics of a normal T wave?

Answer 10

Upright in 1-2, V3-6
Inverted in aVR
Variable in other leads

Question 11

How much can a T wave be elevated in standard leads?

How about precordial leads?

Answer 11

<5mm

<10mm

Question 12

What can QT abnormalities mean?
What can T wave abnormalities mean?
What does ST elevation mean?
What does Q/QRS abnormalities mean?

Answer 12

• MI, injury or ischemia
• STEMI, MI, hyperkalemia
• MI
• necrosis

Question 13

What Is the axis reading? 
1 = +, aVF = +
1 = +, aVF = -
1 = -, aVF = +1
1 = 1 -, aVF = -

Answer 13

Normal axis (0/-30 to +90)
LAD
RAD
Extreme axis deviation

Question 14

What are 2 ways to calculate rate?

Answer 14

• Use QRS alignment and count

- Divide 300 by number of large boxes

Question 15

What is always important to keep in mind when seeing EKG abnormalities?

.

Answer 15

Correlate with history, more alarming if there are symptoms like CP etc.. Some healthy people just have abnormal waves

Question 16

What does a wide P wave mean?

What does a prominent P wave mean?

Answer 16

P mitrale - left atrial enlargement

P pulmonale - pulmonary disease

Question 17

What does prominently depressed ST segment mean?
What does flat ST segment mean?
What does prominently elevated ST segment mean?

Answer 17

• CAD
• ischemia
• MI (but can also be normal depending on person, correlate with hx)

Question 18

What needs to be present for normal sinus rhythm reading?

What leads are best for reading these?

Answer 18

P waves before QRS

2 and V1

Question 19

If P-R is normal length, what does that mean?

If QRS is normal length, what does that mean?

Answer 19

• No AV block

- No bundle branch block

Question 20

If P waves appear after QRS, what does that mean?

If P there are no P waves, what does that mean?

Answer 20

• SVT, junctional rhythm

- Afib, flutter, vtach

Question 21

Draw the 12 axis schematic including the areas of positive and negative deflection

Answer 21

Ok

Question 22

How do you determine the precise axis?

Answer 22

Look at 1 and aVF.
Measure boxes from baseline above and below and add them.
Graph the deflections (+ is toward the lead, - is away from the lead).
Where they meet is the precise axis.