ECG

Question 1

What is the speed of an ECG

Answer 1

25mm/sec

Question 2

How is rate calculated

Answer 2

300/number of 5mm squares per R-R interval

Question 3

Describe a normal P wave

Answer 3

<0.25 mV

upright in II III and aVF

Question 4

Describe a normal QRS complex

Answer 4

between 0.06-0.10s

narrow or wide

Question 5

Sinus rhythm

Answer 5

Normal P and QRS
One P followed by one QRS
regular rhythmn

Question 6

no discernible P wave and irregular QRS complexes is indicative of..

Answer 6

Atrial fibrillation

Question 7

What arrthymia gives a sawtoothed appearance

Answer 7

atrial flutter

Question 8

what arrthymia would present with normal QRS but absent P waves

Answer 8

junctional tachycardia

Question 9

what causes a bifid P wave

Answer 9

p-mitrale

left atrial hypertrophy

Question 10

what causes a peaked P wave

Answer 10

p-pulmonale

right atrial hypertrophy

Question 11

what is the normal length of the PR interval

Answer 11

0.12 - 0.2s
time between atrial and ventricular depolarisation
measured from beginning of P to beginning of Q

Question 12

Describe a normal Q wave

Answer 12

<0.04s and <2mm

Question 13

How would ventricular conduction defects present

Answer 13

long QRS complex

Question 14

what is indicated by low voltage of a Q wave

Answer 14

hypothyroidism, COAD, myocarditis, pericarditis and pericardial effusion

Question 15

What indicates left ventricular hypertrophy on an ECG

Answer 15

R wave of greater than 25mm in V5

sum of S wave in V1 and R wave in V5/6 >35mm

Question 16

What indicates right ventricular hypertrophy on an ECG?

Answer 16

Dominant V1 R wave
T wave inversion in V1-3 or V4
Deep S wave in V6

Question 17

What might cause a significant Q wave

Answer 17

acute MI

Pericardial effusion on shown lead III

Question 18

What is a normal QTc interval and how is it calculated?

Answer 18

QT/sqRR

0.38-0.42 s

Question 19

Prolonged QT interval can be caused by

Answer 19

acute Myocardial ischaemia
myocarditis
brachycardia

Question 20

which part of the ECG is usually isoelectric

Answer 20

ST segment

Question 21

what is indicated by ST elevation?

Answer 21

infarction

Question 22

what is indicated by ST depression?

Answer 22

ischaemia

Question 23

in what limb leads is it abnormal for the t wave to be inverted?

Answer 23

I, II and V4 to V6

Question 24

what effects does digoxin have on the ECG

Answer 24

T wave inversion

ST segment sloping depression

Question 25

what is a normal axis of the heart?

Answer 25

between -30 and 90

Question 26

what happens in left axis deviation

Answer 26

• 30 - -90

- ve QRS deflection in II and III

Question 27

what happens in right axis deviation

Answer 27

+90 to +180

-ve deflections in I

Question 28

describe the 3 ECG stages of an acute MI

Answer 28

T wave peaking followed by inversion
ST segment elevation
appearance of new Q waves

Question 29

how does an anterior infarction present on an ECG

Answer 29

Q waves in V2-4

Inverted T waves in leads V4-6

Question 30

how does an anterolateral infarction present on an ECG

Answer 30

Q waves in leads I,II, AVL, V3-5

Raised ST in V2-6

Question 31

how does an inferior infarction present?

Answer 31

Q waves in II and aVF

depressed ST in aVL and V6

Question 32

how does a pulmonary embolism present?

Answer 32

large S wave in I
deep Q in II
inverted T in III

Question 33

hyperkalaemia ECG presentation

Answer 33

tall tented T

widened QRS

Question 34

hypokalaemia ECG presentation

Answer 34

small T waves, prominent U

Question 35

hypercalcaemia ECG presentation

Answer 35

short QT interval

Question 36

hypocalcaemia ECG presentation

Answer 36

long QT interval, small T waves