ECG Flashcards
What are the small boxes equal to?
0.04sec
What are the big boxes equal to?
0.2sec
What is the rate of an ECG?
25mm/sec
Describe the appearance of an ECG with right bundle branch block?
- Think: MaRRoW
- V1 & V2 QRS complex widening
- rsR’ in V1 & V2 (rabbit ears)
Describe the appearance of an ECG with left bundle branch block?
- V1 looks like a “W”
- V6 looks like an “M”
- Think: WiLLiaM
- Wide WRS complex
How do you work out the ECG axis?
- Look for limb lead where QRS complex is equiphasic both + and - and/or small
- The axis lies at 90o to this
What is the normal ECG axis?
-30o to +90o
Describe the appearance of an ECG in myocardial ischaemia?
- ST depression/elevation
- T wave inversion
How do you work out if there is left ventricular hypertrophy through an ECG?
Sum of height of R wave in V5 & V6 + depth of S wave in lead V1 > 35mm
How do you work out if there is right ventricular hypertrophy through an ECG?
- R wave in V1 greater than 7mm
- Right axis deviation S waves in V5-6
What is the treatment plan for an NSTEMI?
- Aspirin
- Anti-thrombin therapy
- Coronary angiography within 9hrs
Describe the appearance of an ECG in myocardial infarction (STEMI)?
- ST elevation (injury)
- T wave elevation (ischaemia)
- Pathological Q waves (dead tissue)
Describe what pathological Q waves are on an ECG?
- Exceeds 0.04sec width
- >2mm depth (2 small squares)
List the 3 inferior ECG leads?
- II
- III
- AVF
List the 3 lateral ECG leads?
- V1-6
- I
- AVL
List the anteroseptal ECG leads?
V1-4
List the 3 anterolateral ECG leads?
- V3-6
- I
- AVL
What is the mnemonic for a pulmonary embolism on ECG?
S1 Q3 T3
What does S1 Q3 T3 stand for?
- Large S wave in lead I
- Q wave in lead III
- Inverted T wave in lead III
How would hyperkalaemia appear on ECG?
- Tall T wave
- Prolonger PR interval
- Widened QRS
- Arrhythmias
How would hypokalaemia appear on ECG?
- Flattened T wave
- Depressed ST
- Tall U waves
- Prolonged QT
- Arrhythmias
How would hypercalaemia appear on ECG?
Short QT interval
How would hypocalcaemia appear on ECG?
- Long QT interval
- Small T waves
How would Digoxin affect an ECG?
- Shortened QT interval
- Down slopping ST depression
- Arrhythmias
How do you work out the ventricular rate of an ECG?
300 ÷ number of big squares per R-R interval in lead II
What is the normal P wave size?
- Height: <0.25mV
- Width: <0.11sec
What is the normal PR interval size?
120-200msec (3-5 small squares)
What is the normal QRS complex size?
<120msec (3 small squares)
Where is T wave inversion normal?
- AVR
- V1
Describe the appearance of an ECG in ventricular fibrillation?
- Highly irregular rythme
- Unmeasurable rate
- Absent P waves
- No QRS
- EKG tracings is a wavy line
What are the 2 shockable rhythms?
- Ventricular fibrillation
2. Ventricular tachycardia
What do you do for un-shockable rhythms?
Give adrenaline
Describe the appearance of an ECG in atrial fibrillation?
- Irregular rhythm
- No P waves
Describe the appearance of an ECG in atrial flutter?
- Regular rhythm
- Saw tooth appearance
- Narrow complex tachycardia
What drug stops parasympathetic activity?
Atropine
Describe the appearance of an ECG superior ventricular tachycardia (SVT)?
- No atrial activity (no P waves)
- Palpations
- Narrow QRS complex
- Tachycardia
What drug would you prescribe for SVT?
Adenosine
Describe the 5 stages of MI seen on an ECG?
- Normal
- ST segment elevation
- Development of Q waves
- ST segment returns to baseline
- T waves become inverted
Where on an ECG would an anterior infarction be seen?
V2-5
Describe the appearance on an ECG posterior infarction?
Dominant R wave in lead V1 (upwards QRS complex)
Describe 1st degree heart block on the ECG?
Wide PR interval
Describe 2nd degree heart block (Mobitz I/ Wenckebach) on the ECG?
Gradual increase in PR interval, then missed beat (no QRS complex)
Describe 2nd degree heart block (Mobitz II/ 2:1) on the ECG?
Alternating impulses not conducted by AVN, 2 P waves per QRS complex
Describe 3rd degree heart block (AVN escape) on the ECG?
- Complete dissociation between P and QRS
- Narrow QRS complex
Describe 3rd degree heart block (ventricular escape) on the ECG?
- Complete dissociation between P and QRS
- Wide QRS complex
Patients with 1st/2nd degree heart block are often _______?
Asymptomatic
What is the angle of left axis deviation?
-90o to -30o
What is the angle of right axis deviation?
+120o to +90o
What is the normal QT interval?
~300ms
What is the normal ST segment?
0.25sec
What 2 leads normally show the tallest QRS complex?
Lead II & AVR
How is the P interval measured?
From the start of the P wave to the beginning of the QRS complex
How is the QT interval measured?
From the beginning of the QRS complex to the end of the T wave
What is a sign of left axis deviation?
Tallest QRS at AVL
What can left axis deviation mean?
Left ventricular hypertrophy
What is a sign of right axis deviation?
Tallest QRS at lead III or AVF
What can right axis deviation mean?
Right ventricular hypertrophy
What can hyperkalaemia cause on the ECG?
Tall peaked T wave
What can cause a prolonged QTc?
- Antiarrhythmic drugs
- Heart failure
- Inherited long QT syndrome
What would the diagnosis be if there was a marked S-T elevation in leads V1-V4, and slight S-T elevation in l and aVL, this is the primary change, the S-T depression in ll, lll. aVF and V6 is a reciprocal change?
Acute antero-septal myocardial ischaemic damage
What would the diagnosis be if there was marked S-T elevation in leads V1-V5?
Recent anterior myocardial infarction
What would the diagnosis be if V1 had an RSR complex and the total QRS duration is 0.14 seconds?
Complete right bundle branch block
What would the diagnosis be if the strip shows sinus rhythm followed by a pause, followed by sinus rhythm again?
Sinus rhythm with a single episode of sinus arrest
What would the diagnosis be if the strip shows QRS complexes being continuously variable and unpredictable in amplitude , duration and frequency?
Ventricular fibrillation
What is P mitrale?
When P is “M” bifid its from left atrial hypertrophy
What is P pulmonale?
When P is peaked then its from right atrial hypertrophy
What does an inverted Q wave mean?
Junctional rhythm, usually due to sinus pathology (P wave originating from the bottom of the atria’s)
How can you quickly tell if the ECG axis is normal?
If there is a positive QRS complex in lead I and AVF
How can you quickly tell if the ECG axis has possible left axis deviation?
If there is a positive QRS complex in lead I but a negative QRS complex in AVF (then go on to check if lead II is positive or negative to confirm)
How can you quickly tell if the ECG axis has possible right axis deviation?
If there is a negative QRS complex in lead I but a positive QRS complex in AVF
How can you quickly tell if the ECG axis has extreme axis deviation?
If there are negative QRS complexes in both leads I and AVF
What should you always remember about the Bazett’s calculation?
Has to be calculated in seconds!!!
What can happen when a prolonged QTc is not treated?
Polymorphic VT –> DEATH
What artery/s supplies the anterior portion of the heart?
LAD
What artery/s supplies the inferior portion of the heart?
RCA
What artery/s supplies the lateral portion of the heart?
Left circumflex artery/ LAD
What artery/s supplies the septal portion of the heart?
LAD
What is the classification of a widespread STEMI?
When you have elevated ST segment in more than 2 places (anterior, inferior, lateral, septal etc)
What does a flattened T wave suggest?
Ischaemic changes
What are U waves?
Positive deflection after T wave and are not pathological
What does pericarditis look like on an ECG?
- PR depression
- Saddle-shaped ST interval
