Cardio week: ECG Flashcards by Sherilyn Chew

Where are the chest leads V1-V6 placed in an ECG

V1: 4th intercostal space RSE
V2: 4th intercostal space LSE
V3: between V2 &amp; V4
V4: apex
V5: L anterior axillary (same level as V4)
V6: L mid-axillary (same level as V4)

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Limb + chest leads:

Which look at chest in coronal/ axial plane?

Limb leads: coronal plane

Chest leads: axial plane

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Where are the most common sites of infarction of the heart

Anterior and inferior aspects

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Which part of the heart is supplied by the RCA?

What leads suggest a problem with the RCA?

Inferior

Leads: II, III, avF

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Which part of the heart is supplied by the LAD?

What leads suggest a problem with the LAD?

Anteroseptal

Leads: V1-V4

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Which part of the heart is supplied by the Cx?

What leads suggest a problem with the Cx?

Lateral

Leads: 1, aVL, V5, V6

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What does the electrical axis indicate

Average direction of spread of ventricular depolarisation

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Lead I/II positive/negative

Which indicates LAD/RAD?

LAD: Lead I positive, Lead II negative

RAD: Lead I negative, Lead II positive

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How long & high should a normal P wave be?

length <0.11s
(2.5 small boxes)

height <2.5mm
(2.5 small boxes)

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What is the significance of an absent P wave?

SA node has not fired eg in Atrial fibrillation

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What might a taller P wave indicate?

Atrial hypertrophy eg in chronic pulmonary disease

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How long should a normal PR interval be?

0.12-0.2s

3-5 small boxes

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What happens to ECG during WPW syndrome?

Briefly explain why.

Shortened PR interval.

WPW: accessory pathway communicates between atria and ventricles, conducts electricity at much higher rate than AV node.

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How long should normal QRS complex be

<0.12s

less than 3 small boxes

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What stage in the cardiac cycle do the following signify

P wave
QRS complex
T wave
U wave
ST segment

P wave: atrial depolarisation

QRS complex: ventricle depolarisation

T wave: ventricle repolarisation

U wave: Purkinje fibre repolarisation

ST segment: ventricle contracting but no electricity flowing (periods between ventricular depolarisation and repolarisation)

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What might tall QRS indicate?

Ventricular hypertrophy

or slim patient

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What might tall T waves indicate?

Hyperkalemia

- Very early MI

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What might prominent U waves indicate?

Hypercalcaemia
Hypokalemia
Digoxin toxicity

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What might ST elevation indicate?

Acute MI
Pericarditis
Brugada syndrome

What might ST depression indicate?

MI at back of heart
previous MI
previous ischaemia

How does A Fib present on ECG

Absence of P waves

How does A flutter present on ECG

Saw tooth appearance

How does MI present on ECG

ST elevation or depression

How does V fib present on ECG

Bag of worms (chaotic activity)

How does V tachycardia present on ECG

Tidy looking QRS complexes

How does SVT present on ECG

Very fast palpitations (very fast QRS complexes)

How does first degree heart block present on ECG

Constant long PR interval

How does Mobitz type I (second degree heart block) present on ECG

PR interval progressively lengthens until QRS complex completely blocked

How does Mobitz type II (second degree heart block) present on ECG

Abnormally wide QRS complex Some missing QRS complex (if serious)

How does complete heart block present on ECG

No link between P waves and QRS complexes. Individual rates of P waves & QRS complexes tend to be constant.

How does a BBB present on ECG

Widened QRS complex

Which lead is always negative in a normal ECG

avR

Which are the only shockable arrhythmias

VT and VF

ST inversion and elevation and depression Which means ischaemia/infarction

ST elevation: infarction ST depression/inversion: ischaemia

What might a prolonged QT interval indicate

Acute MI, myocarditis, bradycardia

4 Types of SVT

1. A fib 2. Paroxysmal SVT 3. A flutter 4. WPW syndrome

Some examples of narrow complex tachycardias

- sinus tachycardia | - a flutter

Some examples of broad complex tachycardias

- ventricular tachycardia | - junctional tachycardia in acute MI

What is considered significant ST elevation (in terms of small square)

1 small square in limb lead 2 small squares in precordial lead

What types of ST depression are more likely to be pathological

- horizontal | - downwards

In which leads is it normal for T wave to be inverted

aVR III V1

4Hs and 4Ts that can cause a cardiac arrest

4H - hypokalemia/hyperkalemia - hypovolemia - hypoxia - hypothermia 4T - toxin - thromboembolism - tamponade - tension pneumothorax

4 life threatening arrhythmias

1. VF 2. Pulseless VT 3. Asystole 4. Pulseless electrical activity

Which 2 life threatening arrythmias are NOT shockable

- Asystole | - Pulseless electrical activity

ECG changes during hypothermia

- bradycardia - 'J' wave - small hump at the end of the QRS complex - first degree heart block - long QT interval - atrial and ventricular arrhythmias