ECG Flashcards
1
Q
What does P wave represent?
A
Atrial depolarisation
2
Q
What does PR interval represent?
A
Time for electrical activity to move between the atria and the ventricles
3
Q
When does PR interval begin and end?
A
Begins at the start of the P wave and ends at the beginning of the Q wave
4
Q
What does QRS complex represent?
A
Depolarisation of the ventricles
5
Q
When does ST segment begin and end?
A
Starts at the end of the S wave and ends at the beginning of the T wave
6
Q
What does ST segment represent?
A
Time between depolarisation and repolarisation of the ventricles (i.e. ventricular contraction)
7
Q
What does T wave represent?
A
Ventricular repolarisation
8
Q
T wave appears as a small wave after the _____________
A
QRS complex
9
Q
When does RR interval begin and end?
A
Begins at the peak of one R wave and ends at the peak of the next R wave
10
Q
What does RR interval represent?
A
Time between two QRS complexes
11
Q
When does QT interval begin and end?
A
Begins at the start of the QRS complex and finishes at the end of the T wave
12
Q
What does QT interval represent?
A
Time taken for the ventricles to depolarise and then repolarise
13
Q
How long does each small square on ECG paper represent
A
0.04 seconds
14
Q
How long does each large square on ECG paper represent
A
0.2 seconds
15
Q
How long does 5 large square on ECG paper represent
A
1 second
16
Q
How long does 300 large squares on ECG paper represent
A
1 minute
17
Q
Placement of V1 chest electrode…
A
4th intercostal space at the right sternal edge
18
Q
Placement of V2 chest electrode…
A
4th intercostal space at the left sternal edge
19
Q
Placement of V3 chest electrode…
A
Midway between the V2 and V4 electrodes
20
Q
Placement of V4 chest electrode…
A
5th intercostal space in the midclavicular line
21
Q
Placement of V5 chest electrode…
A
Left anterior axillary line at the same horizontal level as V4
22
Q
Placement of V6 chest electrode…
A
Left mid-axillary line at the same horizontal level as V4 and V5
23
Q
Placement of red RA electrode….
A
Ulnar styloid process of the right arm
24
Q
Placement of yellow LA electrode….
A
Ulnar styloid process of the left arm
25
Placement of green LL electrode....
Medial or lateral malleolus of the left leg
26
Placement of black RL electrode....
Medial or lateral malleolus of the right leg
27
Which chest leads have septal view of the heart?
V1 and V2
28
Which chest leads have anterior view of the heart?
V3 and V4
29
Which chest leads have lateral view of the heart?
V5, V6, Lead I, aVR, aVL
30
Which chest leads have inferior view of the heart?
Lead II, Lead III, aVF
31
When the electrical activity within the heart travels towards a lead, you get a.....
Positive deflection
32
When the electrical activity within the heart travels away from a lead, you get a......
Negative deflection
33
Deflection on the ECG represents the _________________ while the deflection height represents ___________________
Average direction of electrical travel
The amount of electrical activity flowing in that direction
34
If the R wave is greater than the S wave, it suggests depolarisation is moving _________ lead
Towards the
35
If the S wave is greater than the R wave,it suggests depolarisation is moving ________ that lead
Away from
36
If the R and S waves are of equal size, it means depolarisation is travelling at exactly __________
90° to that lead
37
In healthy individuals, the electrical activity of the heart begins at the ________ then spreads to the ________. It then spreads down the __________ and _________ to cause ventricular contraction
Sinoatrial node (SA)
Atrioventricular (AV) node
Bundle of His
Purkinje fibres
38
In healthy individuals, you would expect the cardiac axis to lie between ________, axis spreads from _________
-30°and +90º
11 o’clock to 5 o’clock
39
The overall direction of electrical activity in a healthy individual is towards leads _________
I, II and III
40
In healthy individuals see positive deflection in leads __________ with __________ showing the most positive deflection
Leads I, II, II
Lead II
41
Lead II shows the most positive deflection as it is.....
The most closely aligned to the overall direction of electrical spread
42
In healthy individuals see the most negative deflection in _______
aVR
43
There is the most negative deflection in aVR as it
Produces viewpoint of the heart from the opposite direction
44
Right axis deviation (RAD) involves the direction of depolarisation being ______, cardiac axis ______
Distorted to the right
Between +90º and +180º
45
Most common cause of RAD is.....
Chronic pulmonary disease
Right ventricular hypertrophy
Left posterior fascicular block
Acute pulmonary embolism
Lateral myocardial infarction
46
Right axis deviation causes the deflection in Lead I to become ___________ and the deflection in Lead aVF to be more ___________
-ve
+ve
47
T or F: RAD is a common finding in very tall individuals
True
48
Light axis deviation (LAD) involves the direction of depolarisation being ______, cardiac axis ______
Distorted to the left
Between -30° and -90°
49
Left axis deviation causes deflection of Lead I becoming __________ and defelection of Lead aVF becoming _________
+ve
-ve
50
Left axis deviation causes deflection of _______ becoming negative (this is only considered significant if the deflection of _______ also becomes negative)
Lead III
Lead II
51
_______________ usually cause left axis deviation
Conduction abnormalities
52
Normal cardiac axis when Lead I ______ and lead aVF _______
+ve
+ve
53
Indeterminate cardiac axis is when Lead I is ______ and Lead aVF is _______
-ve
-ve
54
Causes of LAD
Left anterior fascicular block
Left bundle branch block
Left ventricular hypertrophy
Inferior myocardial infarction
55
Normal adult heart rate
60-100 bpm
56
Tachycardia heart rate
> 100 bpm
57
Bradycardia heart rate
< 60 bpm
58
If regular heart rhythm, heart rate can be calculated using the following method....
300 / Number of large squares present within one R-R interval
59
If irregular heart rhythm, heart rate can be calculated using the following method....
Count the number of complexes on the rhythm strip (each rhythm strip is typically 10 seconds long)
Multiply the number of complexes by 6 (giving you the average number of complexes in 1 minute)
60
Absent P wave on ECG suggest
Irregular rhythm
61
How long should PR interval be
120-200 ms
3-5 small squares
62
How long should QRS complex be
70-110 ms
63
A prolonged PR interval suggests the presence of ___________
Atrioventricular delay (AV block)
64
Typical ECG findings in first-degree heart block
Fixed prolonged PR interval (>200 ms)
65
Typical ECG findings in second-degree (Mobitz Type I) heart block
Progressive prolongation of the PR interval until eventually the atrial impulse is not conducted and the QRS complex is dropped
AV nodal conduction resumes with the next beat, and the sequence of progressive PR interval prolongation and the eventual dropping of a QRS complex repeats itself
66
Typical ECG findings in second-degree (Mobitz Type II) heart block
Consistent PR interval duration with intermittently dropped QRS complexes due to a failure of conduction
The intermittent dropping of the QRS complexes typically follows a repeating cycle of every 3rd (3:1 block) or 4th (4:1 block) P wave
67
Third-degree (complete) AV block occurs when there is _______________________ due to a complete failure of conduction
No electrical communication between the atria and ventricles
68
Typical ECG findings in third-degree (complete) heart block
Presence of P waves and QRS complexes that have no association with each other, due to the atria and ventricles functioning independently
69
Narrow QRS complex has duration of...
<0.12 seconds
70
Broad QRS complex have duration of...
>0.12 seconds
71
Narrow-complex escape rhythms originate _______________
Above the bifurcation of the bundle of His
72
Broad-complex escape rhythms originate __________________
Below the bifurcation of the bundle of His
73
Shortened PR interval indicates ______________ or __________
P wave originates closer to AV node
Atrial impulse getting to ventricle via accessory pathway
74
Typical ECG finding if atrial impulse getting to ventricle via accessory pathway
Delta wave
75
Delta waves indicate...
Ventricles are being activated earlier than normal from a point distant from the AV node
76
A pathological Q wave is _______ the size of the R wave that follows it or _____ in height and______ in width
> 25%
> 2mm
> 40ms
77
R wave progression is the
Transition from S > R wave to R > S wave
78
Transition from S > R wave to R > S wave should occur in _____ or ______
V3 or V4
79
Poor R wave progression is when..
S > R through to leads V5 and V6
80
Poor R wave progression could be a sign of...
Previous MI
Poor lead positioning
81
ST-elevation is significant when it is _________________ or __________________
>1 mm (1 small square) in 2 or more contiguous limb leads
>2mm in 2 or more chest leads
82
ST elevation most commonly caused by....
Acute full-thickness myocardial infarction
83
ST depression ≥ 0.5 mm in ≥ 2 contiguous leads indicates........
Myocardial ischaemia
84
T waves are considered tall if they are ______ in the limb leads and ________ in the chest lead
> 5mm
>10mm
85
Tall T waves can be associated with......
Hyperkalaemia
Hyperacute STEMI
86
Inverted T waves normal in....
V1 and lead III
87
Inverted T wave in leads besides V1 and lead III can indicate
Ischaemia
Bundle branch blocks (V4-6 in LBBB and V1-V3 in RBBB)
Pulmonary embolism
Left ventricular hypertrophy (in the lateral leads)
Hypertrophic cardiomyopathy (widespread)
General illness
88
Biphasic T waves have two peaks and can indicate ____________ and ____________
Ischaemia
Hypokalaemia
89
Flattened T waves are a non-specific sign that may represent _____________ or ___________
Ischaemia
Electrolyte imbalance
90
U wave is a ___________ after the T wave best seen in ______ or ______
> 0.5mm deflection
V2 or V3
91
The _______ the bradycardia the _______ the U wave
Slower
Larger
92
Classically, U waves seen in...
Electrolyte imbalances
Hypothermia
Secondary to antiarrhythmic therapy → e.g digoxin, procainamide or amiodarone
93
Changes in leads with inferior view (II ,III, aVF) of the heart indicate ___________ occlusion
Right coronary artery
94
Changes in leads with anterior view (V3, V4) of the heart indicate ___________ occlusion
Distal Left Anterior Descending Artery
95
Changes in leads with septal view (V1, V2) of the heart indicate ___________ occlusion
Left Anterior Descending Artery
96
Changes in leads with lateral view (I, aVL, V5, V6) of the heart indicate ___________ occlusion
Circumflex artery (Circumflex branch of LCA)
97
Changes in leads I, aVL, V2-V6 of the heart indicate ___________ occlusion
Proximal Left Coronary Artery
98
Tall R in lead V1 indicate ___________ occlusion
Right Coronary Artery
99
What does this image indicate?
ST elevation
100
What does this image indicate?
ST depression
101
Typical ECG finding in Brugada syndrome
Classic ST elevation with partial right bundle branch block pattern in V1/V2
Persistent coved shape ST elevation with T wave inversion in leads V1-V2
102
Downsloping ST segment is typical with...
Therapeutic doses of digoxin
103
Typical ECG finding of RBBB
V1: RSR’ pattern in V1, with (appropriate) discordant T wave changes
V6: Widened, slurred S wave in V6
104
Typical ECG finding of LBBB
V1: Dominant S wave
V6: broad, notched (‘M’-shaped) R wave
105
Typical ECG finding of hypokalaemia
Down slopping ST segment (widespread) in association with T wave flattening or inversion and U wave
106
Typical ECG finding of hyperkalaemia
Peaked T wave
Prolonged QT
Wide QRS complex
P wave flattening
107
What does this ECG show and how to treat?
Ventricular Tachycardia
Treat with emergency DC Cardioversion
108
What does this ECG show?
Atrial Flutter
109
What does this ECG show?
Ventricular fibrillation
110
What does this ECG show?
Ventricular Flutter
111
Diagnostic criteria for LBBB
Broad QRS complex: >120 ms (3 small squares)
Dominant S wave in V1
Broad, monophasic R wave in lateral leads: I, aVL, V5-V6
Absence of Q waves in lateral leads
Prolonged R wave >60ms in leads V5-V6
112
Diagnostic criteria for RBBB
Broad QRS complex: >120 ms (3 small squares)
RSR’ pattern in V1-V3: an initial small upward deflection (R wave), a larger downward deflection (S wave), then another large upward deflection (a second R wave, which is indicated as R’)
Wide, slurred S wave in lateral leads: I, aVL, V5-V6
113
What does ECG for Typical AV Nodal Re-entry Tachycardia show?
Absence of P wave
Pseudo S wave in Lead II
Pseudo R wave in Lead V1
114
What does ECG for Atypical AV Nodal Re-entry Tachycardia show?
Inverted P-wave before QRS complex
115
What are the markers of ischaemia?
T wave changes
- tall
- biphasic
- inverted → common after MI
- flattened
ST depression → generally prognostic
- can be subtle, widespread or deep
116
What are the criteria for thrombolysis
ST elevation with
- >1mm in 2 contiguous limb leads
- >2m in 2 contiguous chest leads
Posterior MI
LBBB
117
Serial changes in STEMI
Normal → Peaked T wave → Degrees of ST segment elevation → Q wave formation and loss of R wave → T wave inversion
118
Q waves.....
Accompanied by loss of R wave height
Develop between 2-24 hours
119
