Cardiology - ECG Flashcards
(86 cards)
1
Q
Which part of the ECG is always down
A
Q
2
Q
Which part of the ECG is always up
A
R
3
Q
What part of the ECG represents dead myocardium
A
Q waves
4
Q
Determining the rate - ECG
A
300/no’ large squares
How many QRS in 10s
5
Q
Determining the rhythm ECG
A
Sinus - Each P wave = followed by QRS
Constant PR interval
6
Q
Normal cardiac axis
A
I + II = +ve
7
Q
RAD
A
I negative
III positive
8
Q
LAD
A
II + III negative
9
Q
P wave appearance RAH
A
Peaked/tall
10
Q
P wave appearance LAH
A
Notched/broad
11
Q
Def PR interval
A
Time from beginning of P wave to beginning of QRS
12
Q
Normal range PR interval
A
0.12 - 0.2
Or
3-5 small squares
13
Q
What does prolonged PR interval indicate
A
1st degree heart block
14
Q
What does a wide QRS indicate
A
Bundle branch block
15
Q
Tall R waves in V1 indicate
A
RVH
16
Q
Tall R waves V6 indicate
A
LVH
17
Q
2 conditions –> ST elevation (2)
A
MI
Pericarditis
18
Q
2 conditions –> ST depression
A
Ischaemia
Digoxin
19
Q
In what leads is T wave inversion considered normal
A
aVR
III
V1/2
20
Q
Where can Q waves be normal
A
I
VL
V5/6
21
Q
Def QT interval
A
From beginning of QRS to end of T wave
22
Q
Normal value QT interval
A
<0.45 s
Or 2 large squares
23
Q
What is a sinus rhythm
A
When electrical activity starts in SAN
Hence P wave
24
Q
What is a normal axis
A
-30 –> +90
25
Conditions --> R axis deviation (10)
```
Infancy
PE
Cor pulmonale
ASD seculum
rvh
RBBB
L post hemiblock
Dextrocardia
LV ectopic rhythm
Congenital heart disease
```
26
Conditions --> L axis deviation (7)
```
L ant hemi block
LVH
WPW syndrome
RV ectopic beats
Mechanical shift
Normal
ASD primum
```
27
Hyperkalaemia ECG
Tall tented T waves
| More PQT waves
28
Hypokalaemia ECG
Flatter T waves
29
Def bradycardia
<40-60bpm
30
Def tachycardia
>120 bpm
31
Def S wave
Any deflection below baseline following R wave
32
Narrow QRS complexes originate from
Above AVN
33
Wide QRS complexes are often x in origin
Ventricular
34
examples of conditions --> T wave inversion
Ischaemia
Ventricular hypertrophy BBBB
Digoxin - sloped ST segments
35
What is meant be: ST segment should be isoelectric
The same level apart between the T wave and the next P wave
36
J point
Between end of QRS complex and start of T wave
37
What is re-entry tachycardia
Impulse --> depolarisation twice in a row at faster rate than norm
= 180-200bpm
38
Why does re-entry tachycardia occur
Nodal re-entry pathways within AVN
39
What is WPW syndrome
Accessory pathway allows electrical signal from ventricles to enter atria --> earlier than norm contraction
--> repeated stim of AVN
40
What is sinus arrhythmia
HR varies between 40-120
| Due to irreg discharge SAN
41
Most common cause sinus arrhythmia
Breathing
| Due to fluctuations in vagal tone
42
What is Atrial ectopic?
Premature discharge of ectopic atrial focus
43
Appearance ECG atrial ectopic
P wave shape different
| Occurs early before next P wave due
44
What are supraventricular ectopics
Ectopic beats originating in AVN or atria
45
What do patients with atrial ectopics complain of
Skipped beat or irreg pulse
46
What condition can atrial ectopics lead to
AF
47
Causes AF
```
use PIRATES
PE
IHD/Idopathic
Rheumatic valve disease
Anaemia/alcohol/age
Thyroid (hyper)
Elevated BP
Sleep apnoea/sepsis
```
48
ECG appearance AF
Irreg baseline
no P waves
Irreg QRS rate
49
How many atrial contractions /min in AF
450-600
50
What is atrial flutter
Atrial rate >250 and no flat baseline between P waves
51
Appearance ECG atrial flutter
Saw toothed baseline
52
diff between AF and atrial flutter
Similar than in both - normal coordination of atria is lost
| But in flutter, there is some element of synchronicity
53
Appearance ventricular ectopic ECG
Broad QRS
Possible inverted P waves
Bigeminy
54
Appearance ventricular tachycardia ECG
Broad abnormal QRS in all 12 leads
HR > 100bpm
Torsades de Pointes
55
In VT which signs indicate immediate electrical cardioversion (4)
BP <90mmHg
Chest pain
HF
Rate >150
56
In VT, in abscence of signs indicating ECV, what Mx should be done
300mg loading dose amiodarone over 30 mins
57
What is VF?
Individual mm fibres can't contract independently, hence = fibrillating --> no cardiac output
58
VF ECG appearance
No QRS
| ECG totally disorganised
59
What is branch block?
Depolarisation reaches septum normally (norm pR interval)
| But abnormal condition through L/R bundle branches of his --> Wide QRS
60
Right bundle branch block
```
IV septum depolarised from Left normal
Hence R wave V1 + small Q V6
Later R depolarisation --> 2nd R wave
Excitation LV --> S wave V1 + R in V6
RV depolarises after L --> R' V1 and deep S wave
```
61
Which lead is RBBB best seen in?
V1
MarroW - M shape V1
W shape V6
62
Left bundle branch block
Septum depolarises from R-->L
Hence Q wave V1 R wave V6
RV depol before LV --> small R V1 and S in V6
Subsequent LV depol --> S wave V1 + S wave V6
Also assoc w/ T wave inversion Lateral leads
63
Which lead is LBBB best seen in?
V6
WilliaM - W shape V1
M shape V6
64
If LBBB is asymp - what condition should be considered
Aortic stenosis
65
If LBBB is associated with chest pain, what condition should be considered
acute MI
66
What is a hemiblock?
LB divides into ant and posterior fascicles
| = hemi block if 1 fasicle blocked
67
Left anterior block - ECG changes
Upward + leftward directoin
Hence LAD >-45'
Rs complex lead III
68
Left posterior block - ECG changes
Bulk depolarisation downward and to right
RAD +>120
S wave I
q wave III
69
Why does QRS not widen in hemiblocks
Because other fascile is intact
70
Causes hemiblocks (4)
Acute MI
Coronary aa disease
HTN
Congenital heart disease + cardiomyopathies
71
What is the voltage criteria for LVH?
Combined height R wave in V5/6 + depth S wave V1 should not exceed 25mm
72
What is heart block
Abnormal conduction from SAN to ventricles
73
PR interval 1st degree heart block
>0.22s
74
What is 1st deg heartblock
Each wave SAN depolarisation = spread to ventricles
| But = delay somewhere along pathway
75
What can 1st degree heart block indicate? (4)
CAD
Acute rheumatic fever
Electrolyte disturbance
Digoxin toxicity
76
What is Sinoatrial block?
SAN depolarises as normal, but fails to rad atria
77
ECG appearance Sinoatrial block
P wave fails to appeare in expected place
Hence no QRS
Subsequent P waves in norm place
78
2nd degree heart block
Excitation intermittently fails to pass through AVN/bundle of his
79
What are the 3 types of 2nd degree heart block
Mobitz II
Wenckebach/Mobitz I
2:1/3:1
80
Mobitz II phenomenon
Constant PR interval
Sometimes = atrial contraction w/ no ventric contraction
Most P followed by QRS
Occasionally, P not followed by QRS
81
Wenckebach phenomenon
Progressive PR lengthening until atrial beat is not conudcted - no QRS
Then cycle repeats
82
2:1 or 3:1 conduction
2x or 3x as many waves as QRS complexes
83
What is complete/3rd degree heart block
Atrial contraction normal
| No beats conducted to ventricles
84
Complete heart block - ECG appearance
P waves dissoc from QRS
| Wide QRS - escape rhytm
85
What is AV dissociation
If escape rhythm from AV junction or ventricles occurs during sinus brady C
86
AV dissociation ECG appearance
QRS slightly higher than P wave rate
