ECG

Question 1

An ECG is?

Answer 1

recording of changes in potential, by electrodes on the body surface to allow measurement of heart electrical activity

Question 2

what information does an ECG provide?

Answer 2

cardiac rate and rhythm, chamber size, electrical axis of heart

Question 3

magnitude of charge vector determined by ____

Answer 3

mass of cardiac muscle

Question 4

direction of charge vector determined by _____

Answer 4

activity of the heart at an instant in time

Question 5

upwards deflection on an ECG is caused by

Answer 5

depolarisation moving towards positive recording electrode

Question 6

downwards deflection on an ECG is caused by

Answer 6

depolarisation moving away from positive recording electrode

Question 7

Lead I is set up as

Answer 7

RA + to LA -

Question 8

lead II is set up as

Answer 8

RA - to LL +

Question 9

Lead III set up as

Answer 9

LA - to LL +

Question 10

what plane do leads I-III and aVF, aVR and aVL look at

Answer 10

frontal coronal

Question 11

what plane do leads V1-6 look at

Answer 11

transverse

Question 12

what causes the upward P wave on lead II

Answer 12

atrial depolarisation spreading left

Question 13

how long does the QRS complex normally last

Answer 13

<100ms

Question 14

what causes Q on lead II

Answer 14

ventricular depolarisation occurs in IV septum and spreads left to right

Question 15

what causes R

Answer 15

main walls of ventricles depolarise

Question 16

What causes S

Answer 16

upper walls of ventricles depolarise

Question 17

what causes T

Answer 17

ventricular repolarisation

Question 18

what is goldbergers method

Answer 18

use of two negative limb leads to create reference point in the middle

Question 19

how long does P wave last

Answer 19

0.08-0.1s

Question 20

how long does QRS last

Answer 20

<0.1s

Question 21

how long is the PR interval and why is it that long

Answer 21

0.12-0.2s, largely AV node delay

Question 22

how long is the time on a small square of ECG trace?

Answer 22

0.04s

Question 23

how do you calculate HR from ECG

Answer 23

300/number of large squares between beats

Question 24

what lead is the rhythm strip

Answer 24

usually lead II

Question 25

what leads pick up inferior heart abnormalities

Answer 25

Lead II, Lead III, aVF

Question 26

what leads pick up coronal heart abnormalities

Answer 26

lead I and aVL

Question 27

what may a normal ECG fail to pick up

Answer 27

stable angina
MI
intermittent rhythm disturbance

Question 28

how do you work out HR from ECG with irregular QRS

Answer 28

count number of QRS in 30 large squares and multiply by 10

Question 29

what would left axis deviation look like on ECG

Answer 29

inversion of aVF

Question 30

What would right axis deviation look like on ECG

Answer 30

inversion of lead I