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Flashcards in ECG Deck (32)
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1

what is the P wave?

atrial depolarisation

2

what is the PR interval?

time taken for atria to depolarise and electrical activation to get through AV node

3

what is the QRS complex?

ventricular depolarisation

4

what is the ST segment?

interval between depolarisation and repolarisation

5

what is the T wave?

ventricular repolarisation

6

what is the normal value for PR interval?

120 - 200 ms
(3 - 5 small squares)

7

what is the normal value for QRS complex?

less than 120 ms
(3 small squares)

8

what is the QT interval?

it is the measure of time to ventricular repolarisation

9

what are the normal values for QT interval?

men = 350 - 440 ms
women = 350 - 460ms

10

what are the bipolar leads?

they form a triangle between both wrists and left leg
right leg = grounding electrode

11

what are the positive and negative poles in bipolar leads?

negative poles are reference electrodes
positive poles are recording electrodes

12

what are the unipolar leads?

aVR, aVL and aVF
they bisect the angles of the triangle form by bipolar leads
they combine 2 electrodes as reference
they are all positive

13

where is V1 unipolar chest lead electrode positioned?

right of sternum
4th intercostal space

14

where is V2 unipolar chest lead electrode positioned?

left of sternum
4th intercostal space

15

where is V3 unipolar chest lead electrode positioned?

between V2 and V4
V2 = 4th intercostal space
V4 = 5th intercostal space

16

where is V4 unipolar chest lead electrode positioned?

left of sternum
5th intercostal space

17

where is V5 unipolar chest lead electrode positioned?

5th intercostal space
anterior axillary line

18

where is V6 unipolar chest lead electrode positioned?

5th intercostal space
mid-axillary line

19

what does an ECG show?

the overall change in voltage over time in the heart

20

what are P waves like in 12 lead ECG?

all positive except aVR

21

what are T waves like in 12 lead ECG?

all positive except for aVR

22

how does a left ventricle dilation / fibrosis in right ventricle show on an ECG?

delay in electrical activity going left

23

how does a right axis deviation show on an ECG?

delay in depolarisation in right side

24

what is a right bundle branch block (RBBB)?

it is a blockage in the right branch of the His-purkinje system
this can cause loss of specialised tissue
can be cause by heart attack or fibrosis

25

what are the characteristics of a right bundle branch block (RBBB) on an ECG?

leads to delay in depolarisation of ventricles
QRS complex gets wider
posterior aspect of septum gets depolarised but is delayed in anterior

26

what are the characteristics of a left bundle branch block (LBBB) on an ECG?

depolarisation of septum from anterior to posterior aspect
positive R in V6 and Q in V1
RV depolarised before left ventricle
big R wave usually because of left ventricle

27

what does an ST segment elevation indicate?

a heart attack

28

how is a heart attack characterised on an ECG?

p wave normal in all
QRS is narrow and negative in V1 and V2 and positive in V3-V6
ST segment is isoelectric normal
ST elevation seen in aVR, aVF and V2

29

what is tachycardia?

high heart rate
> 100 BPM

30

what is bradycardia?

low heart rate
< 60 BPM