Basics

Question 1

Contractility

Answer 1

Conversion of an electrical signal to mechanical action

Question 2

Excitability

Answer 2

Ability of cardiac muscle to respond to stimuli and generate action potential

Question 3

Conductivity

Answer 3

Transfer of action potential from cell to cell- originating in SA node

Question 4

Automaticity

Answer 4

Ability of cardiac cell to spontaneously generate electrical impose without innervation

Question 5

Fast response action potential

Answer 5

• Initiated at SA node

- Na+ channels

Question 6

Slow response action potential

Answer 6

• Initiated at AV node

- Ca++ channels

Question 7

Overdrive suppression

Answer 7

• Inhibitory effect of faster pacemakers on slower pacemakers

Question 8

SA node- Intrinsic rate

Answer 8

60 - 100 BPM

Question 9

Atrial pacemaker- Intrinsic rate

Answer 9

60 - 75 BPM

Question 10

AV Junction- Intrinsic rate

Answer 10

40 - 60 BPM

Question 11

Ventricular pacemaker- Intrinsic rate

Answer 11

30-45 BPM

Question 12

Horizontal axis- 1 small square (sec)

Answer 12

0.04 sec

Question 13

Horizontal axis- 1 large square (sec)

Answer 13

0.2 sec

Question 14

Vertical axis- 1 small square (mV)

Answer 14

0.1 mV

Question 15

Vertical axis- 1 large square (mV)

Answer 15

0.5 mV

Question 16

PR Interval- expected measurement

Answer 16

• 0.12 - 0.20 sec
• 3 - 5 small squares
• Beginning of P to beginning of Q

Question 17

QRS Interval - expected measurement

Answer 17

• <0.12 sec

- 3 small squares

Question 18

QT Interval - expected measurement

Answer 18

• 0.30 - 0.44 sec

- < 1/2 R-R intervale

Question 19

Sinus bradycardia

Answer 19

< 60 BPM

Question 20

Sinus tachycardia

Answer 20

> 100 BPM

Question 21

P -wave

Answer 21

Atrial depolarization

Question 22

QRS Interval

Answer 22

Ventricular depolarization

Question 23

T wave

Answer 23

Ventricular repolarization

Question 24

Sinus arrhythmia

Answer 24

Small change in rate during inspiration/ expiration

• Inspire = increase rate
• Expire = decrease rate

Question 25

Systematic Interpretation

Answer 25

• Calculate Rate
• Identify rhythm
• Determine axis
• Check for hypertrophy
• Consider ischemia/ injury/ infarction

Question 26

Normal sinus rhythm

Answer 26

• Rate 60-100 BPM
• Rhythm- regularly regular
• P: QRS = 1:1
• PR Interval 0.12 - 0.2 sec
• QRS < 0.12 sec
• QT 0.3 - 0.44 or <1/2 R-R