CVS 7.2 - ECG Abnormalities Flashcards Preview

ESA 2 > CVS 7.2 - ECG Abnormalities > Flashcards

Flashcards in CVS 7.2 - ECG Abnormalities Deck (19):
1

What causes ventricular ectopic beats?

Ventricular cells gain pacemaker activity

2

What happens as a result of ventricular ectopic beats?

- Causes premature ventricular contraction

- Happens every other beat etc or in couplets, triplets etc

3

How does a ventricular ectopic beat change the ECG wave?

Gives a wide QRS complex due to a slower depolarisation of the ventricle as the purkinje fibres aren't being used

4

What is atrial fibrillation?

A quivering and irregular heartbeat due to the muscles contracting in an uncoordinated way

5

How does the ECG wave differ during atrial fibrillation?

- P waves are absent as there is no coordinated spread of depolarisation

- Has irregularly irregular fibrillation waves instead

6

What causes atrial fibrillation?

- Many points in the atria behaving like pacemakers

- Overwhelms AVN (has a refractory period)

- No coordinated spread of depolarisation due to multiple depolarisation points

7

Why is the QRS complex unchanged during atrial fibrillation?

QRS = in ventricles where activity is normal so still contracts

8

What is ventricular fibrillation?

Uncoordinated contraction of the ventricular myocardium causing the muscle to quiver

9

How does the ECG wave differ during ventricular fibrillation?

- Abnormal waves due to chaotic and fast ventricular depolarisation

- Looks like shit

10

What happens as a result of ventricular fibrillation?

- No contraction

- No cardiac output, no pulse

- MI

11

What is heart block?

A communication problem between the atria and ventricles

12

How does the ECG wave differ during 1st degree heart block?

- Prolonged P wave (longer than 0.2s)

- Indicates that the AVN is holding the impulse for too long

- Still has ventricular contraction because electrical signals still reach the ventricles

13

How does the ECG wave differ during mobitz 1 second degree heart block?

- Erratic P-R interval

- P-R elongates until QRS complex is dropped

- Indicates AVN is taking longer in the refractory period

14

How does the ECG wave differ during mobitz 2 second degree heart block?

- Regular P-R interval

- Leads to dropped QRS complexes

- Indicates that excitation isn't passing through the AV node/bundle of His = not all atrial contractions result in ventricular contractions

15

What does mobitz 2 second degree heart block lead to?

- Third degree heart block

- Sudden death

16

How does the ECG wave differ during third degree heart block?

- Inverted QRS complex

- Indicates no AVN conduction = no excitation to the ventricles

- No ventricular contraction but atria are fine

17

Can the ventricles contract during third degree heart block? Why?

- Yes due to ectopic pacemaker cells

- Beats are usually slow

18

What is a bundle branch block?

A delay/obstruction of the electrical excitation in the bundle branches/fascicles

19

What change in the ECG wave is an early indicator of MI?

S-T elevation (indicates injured tissue)

Decks in ESA 2 Class (63):