Basics of ECG

Question 1

Cells are polarized how in cardiac cells?

Answer 1

negatively to -90mV

Question 2

how are cardiac cell depolarisation different from nerve cells?

Answer 2

calcium cells open to prolong the action potential

Question 3

what makes pacemaker cells different?

Answer 3

They have gradual depolarisation during phase 4 rather than straight line

Question 4

how to speed up or slow down heart?

Answer 4

sympathetic: faster
Vagal: slower

Question 5

is AV node blocked, how does ventricle contract?

Answer 5

other pacemaker cells take over

Question 6

what is escape rhythm? Sinus brady cardia and heart block

Answer 6

when AV node, atrium or ventricle sets pace instead of SA node

Question 7

how fast does cardiac muscle conduct compared to bundle branch?

Answer 7

0.5m/s vs. 2m/sec

Question 8

AV node conduction altered? when does it matter?

Answer 8

Yes via vagus

important during atrial fibrillation

Question 9

P wave denotes?

Answer 9

atrium

Question 10

T and U waves denotes?

Answer 10

ventricular repolarisation

Question 11

QRS denotes?

Answer 11

ventricular depolarisation

Question 12

QT denotes?

Answer 12

the action potential duration

Question 13

what does PR denote?

Answer 13

the AV node

Question 14

scaling of a standard ECG is?

Answer 14

25mm/sec

10mm/mV

Question 15

Before reading ECG, do what?

Answer 15

Name
Date
Time
Scaling

Question 16

first thing to read on ECG?

Answer 16

Rate: either count how many QRS waves

Question 17

P waves best seen in which leads? why is P wave important?

Answer 17

Lead II
V1
Key to working out rhythm

Question 18

how do you get slower ventricular depolarisation?

Answer 18

cell-to-cell conduction from venticular pacemaker

Question 19

what is junctional escape? from sinus bradycardia

Answer 19

when it’s not SA node controlling, more AV node or junction because of bradycardia. There is no P wave

Question 20

difference between escape and etopic beats?

Answer 20

escape: after and late
Ectopic: early and after normal beat, pacemaker firing early

Question 21

Wide QRS cause?

Answer 21

BBB
ventricular focus
pacemaker
alternate pathway

Question 22

LBBB what happens to V6?

Answer 22

positive to V6, upwards

Question 23

in RBBB what is V1 and V6?

Answer 23

Late wave Positive in V1

late wave Negative in V6

Question 24

I can be POSITIVE about side of block:

Answer 24

Positive in V6: LBBB

Positive in V1: RBBB

Question 25

Hemiblock interval looks like how in QRS?

Answer 25

Normal QRS interval

Question 26

what determines AV node rate?

Answer 26

the refractory period

Question 27

AF Drugs: ABCDV

Answer 27

Verapamil

Amioradone, Adenosine
Beta-blockers
Calcium channel blocker
Digoxin, diltiazem

Question 28

Ventricular escape rhythm properties?

Answer 28

wide QRS

regular rhythm

Question 29

Atrial flutter?

Answer 29

circular impulses in atrial