Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Clinical skills Yr2 > Data interpretation: ECG > Flashcards

Data interpretation: ECG Flashcards

(73 cards)

Start Studying
1
Q

Before ECG interpretation, which 3 things do you confirm?

A

Patient name and DOB

Date and time of ECG

Calibration of ECG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What should the calibration of the ECG be?

A

Paper speed: 25mm/s

Voltage: 10 mm/mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

After confirming details, what should you assess first in ECG interpretation?

A

Heart rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How do you calculate the heartrate in ECG interpretation, in 2 ways?

A
  1. 10 second method: Count number of R waves in the rhythm strip and multiply by 6 to get total beats in 60 seconds
  2. Box method: Count number of large squares in an R-R interval, then do 300 divided by this number
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

In ECG interpretation, when is it best to use the 10 second method or box method for calculating heartrate?

A

Box method: Use if rhythm looks regular

10 second method: Use if rhythm looks irregular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the normal range for heartrate?

A

Normal: 60-100 bpm

Bradycardic: Less than 60 bpm

Tachycardic: More than 100 bpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

In ECG interpretation, what is the main thing to check for heartrate?

A

Is it normal, tachycardic or bradycardic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In ECG interpretation, what should you check after heartrate?

A

Rhythm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In ECG interpretation, what is the main thing to check for rhythm?

A

Is it sinus rhythm (regular), regularly irregular or irregularly irregular

Sinus/Regular: Consistent interval
between all beats

Regularly irregular: Beats are not evenly spaced, but there’s a organised pattern to the irregularity

Irregularly irregular: Beats are completely chaotic with no organised patterns

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do you assess the rhythm in ECG interpretation?

A
  1. Use another paper to mark consecutive R waves on the rhythm strip
  2. Move paper along the ECG rhythm strip to see if all R-R intervals are the same length
  3. If all R-R intervals are the same length, this is sinus rhythm
  4. If all R-R intervals are not the same length, this is irregular rhythm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

After checking rhythm, what do you assess next in ECG interpretation?

A

Cardiac axis deviation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the cardiac axis?

A

Overall direction of heart’s electrical activity during ventricular depolarisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do you check cardiac axis deviation in ECG interpretation?

A
  1. Look at leads
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does normal axis look like on an ECG?

A

Positive deflection in leads I, II, III

Most positive deflection is in lead II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does right axis deflection look like on an ECG, and which 3 conditions does it indicate?

A

Negative deflection in lead I and positive deflection in lead III (pointing towards each other)

Positive deflection in lead II

Indicates right ventricular hypertrophy, right bundle branch block, pulmonary hypertension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does left axis deflection look like on an ECG, and which 4 conditions does it indicate?

A

Positive deflection in lead I and negative deflection in lead III (pointing away from each other)

Negative deflection in lead II is what confirms left axis deviation (if it was positive deflection then it would still be considered normal axis deviation)

Indicates left ventricular hypertrophy, inferior myocardial infarction, preexcitation syndromes (eg. WPW), left anterior fascicular block

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

In ECG interpretation, what should you check after cardiac axis?

A

P waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What 3 things do you check for P waves, in ECG interpretation?

A

Are they absent or present

If P waves are absent, is there still any atrial activity

Morphology of P waves

Is there a P wave before every QRS complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do you check whether P waves are present?

A

Check lead II/rhythm strip: Should be small, rounded, symmetrical waveform with positive deflection, and should precede QRS complexes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

If P waves are absent, which 2 types of atrial activity should you look for?

A

Atrial flutter: Sawtooth pattern due to flutter waves

Atrial fibrillation: Disorganised pattern due to fibrillation waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are atrial flutter and atrial fibrillation?

A

Atrial flutter: Supraventricular tachycardia due to re-entrant circuit in right atrium, which causes regular but rapid atrial contractions

Atrial fibrillation: Supraventricular tachycardia due to ectopic sites (eg. pulmonary veins) firing random electrical signals and reentrant circuits in left atrium, which causes irregular and rapid atrial contractions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the normal morphology of a P wave?

A

Small, rounded, symmetrical waveform with positive deflection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Which 2 abnormal P wave morphologies do you check for, and what condition do they indicate?

A

P Pulmonale: Tall, peaked P waves due to right atrial hypertrophy, usually secondary to pulmonary hypertension

P Mitrale: Broad, bifid (m) P waves due to left atrial hypertrophy, usually secondary to mitral stenosis or regurgitation or systemic hypertension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

If there isn’t a P wave preceding each QRS complex, what 3 kinds of conditions can this indicate?

A

Atrial arrhythmias: Atrial fibrillation/atrial flutter

Ventricular arrhythmias: V tach, V fib

Heart blocks: AV block, bundle branch block, tachybrady syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
After checking P waves, what should you assess in ECG interpretation?
PR interval
26
How long is a normal PR interval, and how do you calculate it?
Normal PR interval: 120-200 ms (3-5 small squares) From beginning of P wave upslope to beginning of QRS complex
27
What are the causes of prolonged PR interval?
AV block: Commonly due to idiopathic fibrosis or sclerosis, ischaemic heart disease Medications: Beta-blockers (eg. Propranolol, atenolol), CCBs (eg. Verapamil, diltiazem), digoxin, amiodarone, tricyclic antidepressants (eg. Amitriptyline) High vagal tone and increased parasympathetic activity: Vagus nerve slows AV node conduction
28
What are the 4 types of AV block?
1st degree AV block: Electrical impulse from atria to ventricles is slowed, but all atrial impulses pass through and cause ventricular contraction 2nd degree AV block: Electrical impulses from atria to ventricles are slowed, and not all atrial impulses are conducted to ventricles (some dropped ventricular beats) - Type 1 and type 2 3rd degree AV block: Complete atrioventricular dissociation, so no atrial impulses are conducted to ventricles, so ventricular escape rhythms occur to let ventricles beat independently
29
How can you measure if the PR intervals are consistent, in ECG interpretation?
1. Mark on another paper where the PR interval is 2. Move it along the rhythm strip to see if PR intervals are consistent and if it always precedes QRS complex (that there are no dropped beats)
30
What are the main ECG findings in first degree heart block, and explain why?
Fixed prolonged PR interval, before every QRS complex Because there is a delay between atrial contraction (P wave) and ventricular contraction (QRS) so PR is prolonged, all atrial impulses are conducted so there are no dropped beats/QRS complexes Because this occurs between SA node and AV node
31
What are the 2 types of second degree heart block?
Mobitz type 1/ Wenckebach Mobitz type 2
32
What are the main ECG findings of Wenckebach heart block, and explain why?
PR interval elongates until a P wave is not followed by a QRS complex (dropped beat) Delay between atrial contraction and ventricular contraction increases until an atrial impulse isn't conducted to the ventricles and so there is no ventricular contraction (no QRS): Repetitive pattern gives warning for dropped beat Because this occurs in AV node (Only piece of conductive tissue in the heart which exhibits the ability to conduct at different speeds)
33
What are the main ECG findings of Mobitz type 2 heart block, and explain why?
Fixed prolonged PR interval until a P wave is not followed by a QRS complex (dropped beat) Delay between atrial contraction and ventricular contraction is consistent until a random atrial impulse isn't conducted to the ventricles and so there is no ventricular contraction (no QRS): No warning for dropped beat Because this occurs after the AV node, in bundle of HIS or purkinje fibres
34
What are the main ECG findings of third degree heart block, and explain why?
Regular P-P intervals (distance between P waves) and regular R-R intervals, but no association with each other Very bradycardic
35
In ECG interpretation, what else should you check when there is heart block?
Conduction ratio: How many P waves are there for each QRS complex 1st degree heart block: Always 1:1 conduction ratio Wenckebach heart block: Usually one less QRS complex than P waves eg. 3:2 Mobitz type 2 heart block: 2:1, 3:1 3rd degree heart block: No conduction ration due to complete AV dissociation
36
What are the causes of a shortened PR interval?
Pre-excitation syndromes eg. Wolf-Parkinson-white syndrome, lown-ganong-levine syndrome Low atrial rhythm (electrical impulse originates lower in the atria near the atrioventricular (AV) node): Distance the SA node impulse travels before reaching the AV node is shorter
37
What is Wolf-Parkinson-White syndrome, and what are the main ECG findings?
Congenital accessory pathway called bundle of Kent, between the atria and ventricles which causes rapid heartbeat ECG findings: Shortened PR interval, delta wave
38
After checking the PR interval, what should you assess in ECG interpretation?
QRS complex
39
What are the main 3 things to check on QRS complexes, in ECG interpretation?
Width Height Morphology
40
What is the normal width of a QRS complex, and what is the umbrella term for this?
Less than 120 ms (3 small squares) Narrow QRS complex
41
What is the width of a narrow-complex QRS complex, and why does it occur?
Less than 120 ms (3 small squares) Normal ventricular depolarisation: No abnormal conditions
42
What is the width of a broad-complex QRS complex, and why does it occur?
More than 120 ms (3 small squares) Abnormal ventricular depolarisation: BBB, hyperkalemia, WPW or pre-excitation syndromes, aberrant ventricular contraction
43
What is right bundle branch block, and what causes it?
Electrical signal to the right ventricle is delayed or blocked, causing the right side of the heart to beat after the left Depolarisation through the bundle of His occurs only via the left bundle branch. The left branch still depolarises the septum as normal. This left impulse eventually depolarises the right ventricular walls
44
What is the ECG finding of right bundle branch block?
MaRRoW M shaped QRS complex in lead VI W shaped slurred S wave in lead V6
45
What is left bundle branch block, and what causes it?
Electrical signal to the left ventricle is delayed or blocked, causing the left side of the heart to beat after the right Depolarisation through the bundle of His occurs only via the right bundle branch. Septum is abnormally depolarised from right to left. This right impulse eventually depolarises the left ventricular walls
46
What is the ECG finding of left bundle branch block?
WiLLiaM W shaped slurred S waves in lead VI M shaped QRS complex in lead V6
47
How can you tell if the QRS complexes are abnormally tall, and what does it indicate?
QRS complexes will be 'tall and touching' Indicates ventricular hypertrophy, usually left
48
Which abnormal morphologies should you look for in QRS complexes?
Delta wave Pathological Q waves R --> S wave progression J point segment
49
What is a delta wave, and what condition does it indicate?
Slurred upstroke of the QRS complex Associated with accessory pathway eg. WPW syndrome
50
What are pathological Q waves, and what condition does it indicate?
Q wave that is at least 25% of the height of the partner R wave and/or they are greater than 0.04 seconds in width (1 small square) and greater than 2mm (two small squares) in depth Indicate full thickness myocardial death due to previous MI
51
What makes the presence of pathological Q waves more likely, in ECG interpretation?
Pathological Q waves seen in a whole territory eg. anterior/inferior
52
What is normal R ---> S wave progression, in ECG interpretation?
R wave in smallest in V1, lengthens until it becomes taller than S wave in V3/V4, and it tallest in V6 Abnormal progression suggests MI
53
What is the J point segment?
Point in time marking the end of the QRS and the onset of the ST segment
54
What abnormality do you look for in the J point segment, and what does it indicate?
High-take off (J point elevation) Benign early repolarisation, a normal variant in people under 50 yrs old
55
How do you tell the difference between J point elevation and STEMI?
J point elevation: T wave is also elevated STEMI: T wave height stays the same
56
After assessing the QRS complex in ECG interpretation, what should you check next?
ST segment: Between end of S wave and start of T wave
57
What is the normal finding of ST segments?
Flat across the isoelectric baseline (PR segment)
58
What does ST elevation indicate?
Full thickness myocardial infarction: Permanent lack of blood flow resulting in heart muscle death STEMI
59
What does ST depression indicate?
Myocardial ischaemia: Temporary lack of blood flow to heart muscle cells NSTEMI
60
What does an anterior/septal STEMI look like on ECG?
ST elevation in leads V1-V4 (septal is V1,V2 and anterior is V3,V4) Reciprocal ST depression in II, III, aVF (inferior leads)
61
If a patient has an anterior/septal STEMI, which coronary artery is affected?
Left anterior descending (LAD) artery
62
What does a lateral STEMI look like on ECG?
ST elevation in leads V5, V6 and I, aVL Reciprocal ST depression in II, III and aVF (inferior leads)
63
If a patient has a lateral STEMI, what coronary artery is affected?
Left circumflex artery: ST elevation seen in V5, V6 and I, aVL Diagonal branch of Left anterior descending artery: ST elevation seen in I and aVL only
64
What does an inferior STEMI look like on ECG?
ST elevation: II, III, aVF Reciprocal ST depression: I, aVL (some lateral leads)
65
If a patient has an inferior STEMI, what coronary artery is affected?
Right coronary artery (RCA): Most common Left circumflex artery
66
What does a posterior STEMI look like on ECG?
ST elevation: V7,V8,V9 (posterior leads) Reciprocal ST depression: V1,V2,V3,V4 (anterior septal leads)
67
If a patient has a posterior STEMI, what coronary artery is affected?
Posterior descending artery Left circumflex artery
68
What is the characteristic finding of acute pericarditis on ECG?
Global saddle-shaped ST elevation
69
After checking ST segment in ECG interpretation, what should you assess next?
T wave
70
What do tall, tented T waves suggest?
Hyperkalemia or hyperacute STEMI
71
What do flattened or inverted T waves suggest?
Hypokalemia
72
What is a U wave?
Small (0.5 mm) deflection immediately following the T wave, usually in the same direction as the T wave Indicates hypokalemia, antiarrhythmic drugs (eg. digoxin, amiodarone)
73
brugada digoxin toxicity

Clinical skills Yr2 (38 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions