ECG's

Question 1

cardiac electrical conduction cycle

Answer 1

SA node causes contraction –> AV node –> bundle of HIS –> bundle branches –> purkinje fibers

Question 2

cardiac mechanical conduction cycle

Answer 2

atrial depolarization/systole (P wave) –> ventricular depolarization/systole (QRS) –> ventricular re-filling (T wave)

Question 3

SA node

Answer 3

the pacemaker
- located in right atrium
- 60 to 100 bpm

Question 4

AV node

Answer 4

gatekeeper/delivers down bundle of HIS
- can take over if SA node fails

40-60 bpm

Question 5

5 lead ECG placement

Answer 5

• snow above grass (left)
• smoke over fire (right)
• brown in the middle (4th intercostal)

Question 6

small box

Answer 6

0.04 seconds

Question 7

big box

5 small boxes

Answer 7

0.20 seconds

Question 8

6 seconds

Answer 8

30 box chunks
- count QRS complex to determine rate

Question 9

steps to interpretation

Answer 9

1. regularity
2. P:QRS ratio (determines sinus)
3. morphology (determines consistency)
4. rate
5. measure intervals
6. interpret

Question 10

determiming rate

atrial vs ventricular

Answer 10

atrial= # of P waves x10
ventricular= # of QRS complex x10

if there is P wave for every QRS complex you only need to determine one

Question 11

arrhythmias

Answer 11

occur from abnormal pacemaker due to
- disturbance in impulse formation, disturbance in impulse conduction, or both

Question 12

artifact

Answer 12

abnormal readings on waveform that may not coordinate with an arrhythmia

Question 13

Atrial fibrilation

Answer 13

AV node still working but too many impulses which leads to blood pooling in atria and can cause clotting which leads to stroke or PE

treat with anticoagulant; will not be able to determine P or T wave

Question 14

Atrial flutter

Answer 14

“saw tooth” P wave
- proceeds A-fib

treat with anticoagulant and electrode procedure

Question 15

SVT

Answer 15

unable to visualize P wave and no P:QRS ratio, very narrow QRS complex
- rhythm originates from above ventricles

can treat with cardioversion

Question 16

ventricular tachycardia

Answer 16

no T wave or PR interval just up and down lines but wavy; very wide QRS complex
- can have pulse or pulseless
- check for S+S (will show as low BP, diaphoretic)
- can treat with cardioversion and medications

fast rate, morphology of QRS complex

Question 17

ventricular fibrilation

Answer 17

squiggly lines
- no pulse; must call code

ventricles quivering

Question 18

asystole

Answer 18

no cardiac conduction
- first thing to do is check patient just in case leads are just misplaced
- call code

Question 19

first degree AV block

Answer 19

AV node taking time sending from atria to ventricles
- will see long PR measurement
- may be due to ischemia

Question 20

second degree AV block type 1

Answer 20

PR interval changes in each segment

Question 21

second degree AV block type 2

Answer 21

random drops in QRS complex

Question 22

third degree AV block

Answer 22

irregular P:QRS ratio
- loss of synchronicity between atria and ventricles
- will see 30 bpm in ventricular
- atrial rate would be 60-80 bpm

Question 23

PR interval

Answer 23

beginning of P to beginning of Q
- 0.12-0.20 seconds (3-5 small boxes)

Question 24

QT interval

Answer 24

beginning of Q to end of T
- 0.36-0.44 seconds (9-11 small boxes)

Question 25

ST segment

no time

Answer 25

end of S to beginning of T
- tells us about MI

Question 26

QRS complex

Answer 26

0.06-0.12 seconds (1-3 small boxes)

Question 27

lethal arrythmias

4

Answer 27

• pulseless ventricular tachycardia
• ventricular fibrilation
• asystole
• pulseless electrical activities