ECG Interpretation Flashcards
(73 cards)
1
Q
What is important when idetifying an ECG?
A
Confirm the patients name and age along with the ECG date
2
Q
What is the standardisation of an ECG?
A
- 1cm = 1mV
- Paper speed = 25mm/sec
3
Q
How is the rate of an ECG calculated?
A
300 divided by the number of big squares per R-R interval
4
Q
What ECG lead is used to calculate the rate?
A
Lead II
5
Q
What is normal rate?
A
60-100bpm
6
Q
Bradycardia
A
<60 bpm
7
Q
Tachycardia
A
>100 bpm
8
Q
What does an ECG record?
A
electrical impulses start and how they flow through the heart.
9
Q
Where does the elctrical activity of the heart start?
A
“internal pacemaker” called the sinoatrial node
10
Q
What is normal rhythm referred to as?
A
sinus rhythm
11
Q
What is conduction?
A
The way electrical impulses floe through the heart
12
Q
When should you take an ECG?
A
- Chest pain
- Palpitations
- breathlessness
- dizziness
- an episode of synocope (blackout)
- unexplained fall
- Stroke
- TIA
13
Q
What plane do the chest leads look at the heart from?
A
horizontal
14
Q
What plane do the 6 limb leads look at the heart from?
A
vertical
15
Q
What is sinus rhythm?
A
- Normal P waves (2.5 boxes)
- Normal QRS complex (3 boxes)
- One P wave followed by one QRS complex
16
Q
How do you check if rhythm is regular?
A
Mark position of 3 successive R waves.
Slide the mark forward and check that intervals are equal
17
Q
Characteristics of Atrial Fibrillation
A
- No discernible P waves
- Irregular QRS complex
18
Q
Charactertistics of Atrial Flutter
A
- P waves can be seen at a rate of 300bpm, giving a saw-toothed appearance
- 4 P waves per QRS complex
- Ventricular activation is regular
19
Q
Characteristics of Nodal Rhythm
A
- Normal QRS complex
- P waves are absent
20
Q
Another name for nodal rhythm
A
Junctional Tachycardia
21
Q
Characteristics of Ventricular Rhythm
A
- two sinus beats and the rate increases to 150bpm
- QRS complex becomes broad and T waves are difficult to identify
- Final beat shows a return to sinus rhythm
22
Q
What does the P wave represent?
A
Atrial depolarisation
23
Q
In what leads in the P wave upright?
A
- II
- III
- AVF
24
Q
In what conditions are P waves absent?
A
- Atrial fibrillation
- Nodal (junctional) rhythm
25
What is the maximum height of a P wave?
2.5 boxes
26
What occurs in abnormal P wave; P-Mitrale
2 P waves per QRS complex
27
What causes a bifid P wave?
left atrial hypertrophy
28
What occurs in abnormal P waves; P-Pulmonale
P wave is too tall
29
What causes a peaked P wave?
Right atrial hypertrophy
30
What is the P-R interval
Bgeining of P wave to the beginning of Q wave
31
What is the normal range of the PR interval?
120-200ms (3-5 boxes)
32
What does the PR interval represent
time between atrial and ventricular depolarisation
33
What does a prolonged PR interval imply?
(\>0.2s)
delayed AV conduction
34
What is defined as the QRS complex?
Beginning of Q to the end of S wave
35
What is the normal duration of the QRS complex?
0.12s (3 boxes)
36
What is the normal length and depth of a Q wave?
length = 0.4s
depth = \<2mm
37
What condition(s) are suggested if the QRS complex is 120ms?
* Ventricular conduction defects
* Bundle branch block: left and right
38
What condition(s) are likely in a low voltage \<5mm QRS complex?
* Hypothyroidism
* Chronic obstructuve airway disease
* myocarditis
* pericarditis and pericardial effusion
39
What are the main features of Left Ventricular Hypertrophy
* R wave in V5 \>25mm
* Sum of S in V1 and R wave in V5 or V6 \>35mm
* Sokolow-Lyon index
\*\*V5 must not be \>25mm
40
What are the main features of right ventricular hypertrophy?
* Dominant R wave in V1
* T wave inversion in V1-V3 or V4
* Deep S wave in V6
41
What is a singificant Q wave?
* \>40ms (wider than 1 box)
* Depth \>2m
42
When is a significant Q wave present?
* Present couple of hours/day after acute MI
* If present in lead III consider PE
43
Where is the QT interval measured?
From the start of the QRS compelx to the end of the T wave
44
QTc =
QT
------------
/RR
45
What are the causes of a prolonged QT interval?
* Acute myocardial iscaemia
* Myocarditis
* Bradycardia
* Head injury
* Hypothermia
* U&E imbalance
* Congenital
* Drugs
46
What is the ST segment?
Time from the end of ventricular depolarisation to the start of ventricular repolarisation
47
What marks the ST segment?
From the end of the QRS complex to the start of the T wave
48
What is an abnormal ST segemnt
* Elevation \>2mm in 2 adjacent chest leads
OR
* Elevation \>1mm in 2 adjacent limb leads
49
What does elevation of the ST segment usually indicate?
INFARCTION
50
Is the ST segment isoelectric?
Yes
51
What does the T wave represent?
Ventricular repolarisation
52
In what leads is the T wave normally inverted?
aVR, V1 and V2 in the young
53
Where it it abnormal for a T wave to be inverted?
I, II and V4-V6
54
What does inversion of a T wave indicate?
Ischaemia or infarction
55
What effect does digoxin have on the T wave?
* T wave inversion
* ST segment sloping depression
56
Between what axis is the heart normal?
-30 - +90
57
In what leads are upward deflections present in normal axis
I, II and III
58
What occurs in left axis deviation and what condition does this indicate?
Negative QRS deflection in II and II
LV hypertrophy and MI
59
What occurs in right axis deviation and what conditions does this indicate?
Negative QRS deflection in lead I
RV hypertrophy, PE and MI
60
What 3 changes occur in an ECG during an MI?
* T wave peaking following T wave inversion
* ST segment elevation
* Appearance of new Q waves
61
What develops in the ECG during a STEMI
1. St elevation
2. Q wave abnormal, R shortened, T inversion
3. ST resolved
4. T reverts, Abnormak Q persists
62
Where can an anterior infract be located?
Any of the percordial leads (V1-V6)
63
Where can a lateral infarct be located?
Leads I, AVL, V5 and V6
64
Where can an inferior infarct be located?
Leads II, III, AVF
65
Where can a posterior infract be located?
Reciprocal changes in lead V1 (ST depression, tall T wave)
66
Features of an anterior infarction
* Sinus rhythm
* Q waves in leads V2-V4
* Inverted T waves in leads V4-V6
67
Features of an antero-lateral infarct
* Sinus rhythm
* Q waves in leads I, II, AVL, V3-V5
* Rasied ST segments in leads V2-V6
68
Features of an inferior infarction
* Sinus rhythm
* Q waves in leads III and AVF
* Depressed ST segments on leads AVL and V6
69
Features of a PE on an ECG
* LArge S wave in lead I
* Deep Q wave in lead III
* Inverted T wave in lead III
70
Hyperkalaemia
Tall, tented T wave, widened QRS
71
Hypokalaemia
Small T waves, prominant U waves
72
Hypercalcaemia
Short QT interval
73
Hypocalcaemia
Long QT interval, small T waves
