Week 4 Flashcards Preview

ECG > Week 4 > Flashcards

Flashcards in Week 4 Deck (55)
Loading flashcards...
1

What is the cardiac axis?

The average direction of electrical activity within the heart during ventricular depolarisation

2

What leads are used to determine the heart's axis?

6 frontal leads

3

Left axis deviation has an angle of what?

beyond -30 degrees

4

Causes of left axis deviation?

1. right sided WPW
2. left anterior hemi-block
3. inferior myocardial infarction
4. ventricular tachycardia

5

Can left ventricular hypertrophy cause LAD?

Yes, but not because of increased muscle mass but instead left anterior hemi-block due to fibrosis

6

Most common cause of left axis deviation?

left-anterior hemi block

7

Block of the RBB and left anterior hemi block is called what?

A bifascicular block

8

Why does inferior MI cause LAD?

Fibrotic tissue doesn't conduct activity and so the cardiac axis becomes directed away from this

9

How does left ventricular tachycardia cause left axis deviation?

When an electrical impulse arises in the LV, the wave of depolarisation spreads through the rest of the myocardium from that point, resulting in LAD.

10

When is right axis deviation diagnosed?

+ 90 degrees

11

What is ventricular asystole?

Ventricular standstill - no electrical activity in the heart - no cardiac output

12

What does asystole look like on the ECG?

A flat line

13

What is the immediate treatment for asystole?

CPR

14

Should asystole be confirmed in more than one lead?

Yes

15

What is another name for asystole

Arrhythmia of death - client is in cardiopulmonary arrest

16

What is sinus bradycardia?

Sinus rhythm below 60bpm - originating in SA node

17

Heart rate must be below what to be a contraindication to EECG?

40 bpm unless they are extremely fit individuals

18

What group of people might get bradycardia?

Athletes - increase in vagal tone

19

By what mechanism does vagal done reduce HR?

Vagal done reduces the automaticity (speed of depolarisation) of pacemaker cells

20

What are the 3 characteristics of sinus bradycardia?

1. P wave proceeds QRS complex
2. P wave is upright in lead II and inverted aVR
3. HR is less than 60bpm

21

Causes of bradycardia?

1. Drugs (digoxin and beta-blockers)
2. Hypothyroidism
3. ischemic heart disease/MI - AV node/Purkinji fibre escape rhythms
4.

22

When is treatment for bradycardia significant?

when CO becomes reduced

23

What are the symptoms of reduced CO?

hypotension, syncope, dizziness,

24

Can bradycardia predispose individuals to more serious arrhythmias?

Yes, e.g. V.fib as irritable focus has an opportunity to fire

25

In acute inferior wall MI, is bradycardia a good or bad prognosis?

Good unless it's associated with hypotension

26

What drugs can enhance HR?

Dopamine, atropine and adrenalin

27

What are 4 non-cardiac causes of sinus bradycardia?

(1) increased intracranial pressure (2) glaucoma (3) sleep (4) hypothermia

28

What is ventricular tachycardia?

3 or more successive beats of HR > 120bpm

29

Is ventricular tachycardia wide or narrow QRS complex?

Wide

30

What causes ventricular tachycardia?

Re-entry or increased automaticity of ventricular foci