ECG Flashcards
What 2 things do you do when checking the calibration of an ECG?
- Ensure 10mm = 1mV
- Ensure paper speed is 25 mm/sec
What does a small box representon an ECG?
0.04 secs or 40 ms
What do the larger boxes on an ECG represent?
5 small boxes = 1 big box
0.2 secs or 200 ms
How do you determine the HR (ventricular rate)?
300 / number of big squares between R waves
(calculated in standard lead II)
Describe a normal P wave
- Height < 0.25 mV
- Width < 110 msec (3 small boxes)
What is a normal PR interval?
120 to 200 msec (0.12 to 0.2 secs)
What does a prolonged PR interval suggest?
Heart block (primary, secondary or tertiary)
What is a normal QRS complex?
What is a wide QRS complex?
Normal < 120 msec
Wide > 120 msec
(120 msec = 3 small boxes)
What is the normal axis of an ECG reading?
-30 to +90 degrees
In what leads is T wave usually inverted?
- Standard lead aVR
- Chest lead V1
In what leads would it be abnormal for a T wave to be inverted?
I, II and V4 to V6
What does a tall/peaked T wave suggest?
Hyperkalaemia
Where is the QT interval measured between?
From start of QRS to end of the T wave
What does QT vary with?
Heart rate
How do you calculate the corrected QTc interval?
QTc = QT / √RR
What is the normal range for QTc?
380 to 420 msec (0.38 to 0.42 secs)
What degrees of the hexaxial diagram does aVR sit at?
-150 degrees
What degrees of the hexaxial diagram does aVL sit at?
-30 degrees
What degrees of the hexaxial diagram does I sit at?
0 degrees
What degrees of the hexaxial diagram does II sit at?
+60 degrees
What degrees of the hexaxial diagram does aVF sit at?
+90 degrees
What degrees of the hexaxial diagram does III sit at?
+120 degrees
What does P in the ECG represent?
Atrial depolarisation
What does T represent in the ECG?
Ventricular repolarisation
What does Q represent in the ECG?
Septum depolarisation
What does R represent in the ECG?
Ventricular (main) depolarisation
What does S represent in the ECG?
Base of heart depolarisation
What are the inferior leads?
III, aVF, II
What are the left lateral leads?
aVL, I, V6, V5
What are the front leads?
V2, V3, V4
What are the chest leads?
V1 - V6
What are the limb leads?
aVL, aVR, aVF, II, III
Describe the order of conduction?
SAN -> AVN -> Bundle of His -> R and L Bundle Branches
Left Bundle Branch -> Anterior and Posterior Fascicles
What are Einthoven’s labelling rules for the QRS?
- First positive is an R
- Any negative preceding an R is a Q
- Negative following an R is an S
- Any further positive following an S is called R1 (R prime)
What are the characteristics of right bundle branch block?
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- M pattern in V1 to V3
- Rabbit ears
- W pattern in V6
State 2 signs of myocardial ischaemia?
- ST depression
- T wave inversion
Comment on the ECG
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NORMAL
Comment on the ECG
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ST DEPRESSION
Comment on the ECG
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T WAVE DEPRESSION
What do you use to determine if there is left ventricular hypertrophy (LVH)?
Sokolow-Lyon criteria
What is sokolow-lyon criteria?
Sum of the height of the R wave in leads V5 or V6 plus the depth o the S wave in lead V1
> 35 mm = LVH
What signs on the ECG would suggest Right Ventricular Hypertrophy?
- R wave in V1 greater than 7mm
- Right axis deviation
- S waves in V5-V6
What are the different types of Acute Coronary Syndrome?
- Unstable angina
- Non-ST segment elevation MI
- ST segment elevation MI
What would be the signs on an ECG of NSTEMI?
- No ST elevation
- Troponin elevated
What does Troponin < 14 ng/L signify?
- Troponin negative
- Unstable angina
What does a troponin between 14 and 99 ng/L suggest?
Myocardial infarction
What does a troponin greater than 99 ng/L suggest?
Myocardial infarction
What are the inferior leads?
II, III, aVF
What are the lateral leads?
V5-V6, I and aVL
What are the anterior leads?
V2-V5
What are the signs on an ECG that may suggest a PE?
S1 Q3 T3 pattern
Inverted Ts V1-V4
What are the ECG signs of hyperkalaemia?
- Tall T waves
- Prolonged PR
- Widened QRS
- Arrhythmias
What are the signs of hypokalaemia?
- Flattened T wave
- Depressed ST
- Tall U waves
- Prolonged QT
- Arrythmias
What is the normal height/amplitude of a T wave?
1/3 to 2/3 of the corresponding R wave
How does hypercalcaemia show on an ECG?
Short QT interval
How does hypocalcaemia show on an ECG?
- Long QT interval
- Small T waves
What does DIGOXIN do to a patients ECG?
- Shortened QT interval
- Characteristic down-sloping ST depression
- “Reverse tick”
- Arrythmias
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First degree heart block?
Delayed PR interval
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2nd-degree heart block Mobitz type 1 (wenckenbachs)?
Signals are delayed more and more until the heart skips a beat then resets
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2nd degree heart block Mobitz type 2?
Some electrical signals don’t reach the ventricles
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Third-degree heart block?
No electrical signals reach the ventricles
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Where do you find the apex beat?
- Left 5th ICS
- Mid-clavicular line
What is a thrill?
What does it indicate?
- Palpable vibration caused by turbulent blood flow
- Aortic stenosis
What is a heave?
What does it indicate?
Vibration felt on the heel of the hand
- Caused by left atrial hypertrophy
- mitral stenosis
- mitral regurgitation
What can the tricuspid valve be auscultated?
- Left 4th ICS
- Sternal edge
What can the pulmonary valve be auscultated?
- 2nd left ICS
- Lateral to sternum
What can the aortic valve be auscultated?
- Right 2nd ICS
- Lateral to sternum
What are the shockable rhythms?
- Ventricular fibrillation
- Pulseless ventricular tachycardia
What drugs should you administer intermittently for shockable rhythms?
- Adrenaline 1mg IV
- Amiodarone 300mg IV
What should the minimum power be for a first shock?
150J
What are the non-shockable rhythms?
- Pulseless electrical activity (PEA)
- Asystole
What drug should you administer intermittently for non-shockable rhythms?
Adrenaline 1mg IV