Basic Waves/Complexes/Intervals (Exam #1)

Question 1

What are the four anterior leads?

Answer 1

V1-V4

Question 2

What are the four lateral leads?

Answer 2

I
aVL
V5, V6

Question 3

What are the three inferior leads?

Answer 3

II, III

aVF

Question 4

What does one “small box” represent horizontally? Vertically?

Answer 4

• Horizontal = 0.04 seconds in duration

- Vertical = 1 mm (0.1 mV) in amplitude

Question 5

What is the NORMAL duration for a P wave? NORMAL amplitude?

Answer 5

P wave

• Duration: 0.06-0.10 seconds
• Amplitude: 0.5-2.5 mm high

Question 6

When does the PR interval start and end?

Answer 6

• Start: P wave

- End: beginning of QRS complex

Question 7

What is the NORMAL duration for a PR interval?

Answer 7

PR interval

- Duration: 0.12-0.20 seconds

Question 8

What deflection correlates with each part of the QRS complex?

Answer 8

• Q wave = first negative deflection
• R wave = any positive deflection following Q wave/PR segment
• S wave = any negative deflection following R wave

Question 9

What is the NORMAL duration for a QRS complex?

Answer 9

QRS complex

- Duration: 0.06-0.12 seconds

Question 10

What is the ST segment? What is the J point?

Answer 10

• ST segment: flat line that follows QRS complex

- J point: where QRS complex meets ST segment

Question 11

When does the QT interval start and end, and what part of the cardiac cycle does it represent?

Answer 11

Time of ventricular depolarization and repolarization

• Start: beginning of QRS complex
• End: end of T wave

Question 12

What is the NORMAL duration for a QT interval? What is it dependent on?

Answer 12

Duration: 0.36-0.44 seconds

- Dependent on HR (as HR decreases, QT interval increases = inverse relationship)

Question 13

What are the NORMAL values for the following:

• Rate?
• Rhythm?
• P wave (2)?
• QRS complex?
• PR interval?
• QT interval?

Answer 13

• Rate: 60-100 bpm
• Rhythm: regular
• P wave: 0.06-0.10 seconds, 0.5-2.5 mm
• QRS complex: 0.0.6-0.12 seconds
• PR interval: 0.12-0.20 seconds
• QT interval: 0.36-0.44 seconds

Question 14

What does a NORMAL P wave look like (2)? NORMAL QRS complex (2)? NORMAL T wave (2)?

Answer 14

• P wave = upright, rounded
• QRS complex = upright, narrow
• T wave = upright, slightly asymmetrical

Question 15

What would the amplitude be for a “tall, rounded or peaked” P wave? What does this indicate?

Answer 15

Amplitude is greater than 2.5 mm

- RAE = “P pulmonale”

Question 16

What would the duration be for a “wide, notched or biphasic” P wave? What does this indicate?

Answer 16

Duration is greater than 0.10 seconds

- LAE = “P mitrale”

Question 17

What are the five steps of EKG analysis?

Answer 17

1. Determine rhythm (regularity)
2. Calculate rate
3. Evaluate P wave
4. Evaluate QRS complex
5. Evaluate PR interval

Question 18

What type of rhythm is the Large-Box Estimate LESS accurate with? What is the number order (300, …), and where do you start/end?

Answer 18

Less accurate with irregular rhythms

• 300, 150, 100, 75, 60, 50
• Start at first R wave on/near a bolded line - next bold line is 300…
• End at next R wave on/near a bolded line (if between, use range)

Question 19

What type of rhythm can the 1500 Method NOT be used with? How does this method work?

Answer 19

CANNOT be used with irregular rhythms

- Count small boxes between two R waves and divide by 1500

Question 20

What type of rate might cause the P wave to be buried in the T wave, and what will the T wave likely look like?

Answer 20

Rapid rates can have P wave hidden in T wave

- T wave will be peaked, notched or larger than normal

Question 21

What pathology might cause a wide/bizarre QRS complex?

Answer 21

BBB (left or right)