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CARDIOLOGY > ECG's > Flashcards

ECG's Flashcards

1
Q

What does 1 small square, 1 large one and 5 large squares represent?

Remember, the whole strip is 12 seconds long!

A
  1. 04s
  2. 2s

1 second

OR JUST DIVIDE 300 BY THE NUMBER OF LARGE SQUARES BETWEEN EACH QRS PEAK

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2
Q

What are the 4 steps for reading an ECG?

A
  1. Rate
  2. Rhythm using rhythm strip
  3. Axis (I, II, III)
  4. P wave
  5. PR interval 6,7,8,9,10, etc…..

SLIDES

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3
Q

How do you calculate the rate?

Rhythm - what do the following mean in terms of ECG’s?

Sinus tachycardia

AF

Atrial flutter - what does this look like on ECG?

A

Number of QRS peaks x5 or 300 divided by number of large squares

Inc/dec with inspirations - regularly irregular

Irregularly irregular

Sawtooth baseline

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4
Q

Axis:

What 3 leads do you look at?

What causes LV deviation?

What causes RV deviation?

A

Lead I, II, III

LVH*

Hemiblock
MI
WPW syndrome

RVH*

Hemiblock
PE
MI
WPW syndrome 
Tall thin person
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5
Q

Chest leads:

How does the QRS complex progress from V1 to V6?

Why is the transition period important?

What part of the heart do the following leads represent:

  • V1 & V2
  • V3 & V4
  • V5 & V6
A

Mainly downwards to mainly upwards

Can indicate some enlargement of the ventricles

Septum

Anterior

Lateral

THE CHEST LEADS BASICALLY LOOK MAINLY AT THE LEFT SIDE OF THE HEART!

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6
Q

What is tachycardia?

Causes - list some

A

> 100bpm

Infection
Pain 
Exercise 
Anxiety 
Dehydration 
Bleed etc.
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7
Q

What is sinus bradycardia?

Causes - list some

A

<60 bpm

Physical fitness 
Vasovagal attacks 
Drugs (Beta-blockers, digoxin) 
Hypothyroidism 
Hypothermia
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8
Q

What is a normal PR interval?

What is a normal QRS complex length?

A

3-5 small squares

0.12 - 0.2 seconds

3-5 small squares

0.12 - 0.2 seconds

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9
Q

1st degree HB - what is it?

What about Rx?

Causes:

  • What heart disease causes this? -2
  • What causes abnormal electrical activity everywhere?
  • What cardiac drug at toxic levels can cause this?
A

PR interval >0.2 seconds - 5 small squares

No Rx needed

Coronary artery disease
Acute rheumatic carditis

Electrolyte imbalance

Digoxin toxicity

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10
Q

2nd degree HB - Mobitz type 1/Wenckebach

What is it?

Rx?

A

Progressively prolonged PR interval until P wave fails to transmit to ventricles

No Rx needed

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11
Q

2nd degree HB - Mobitz type 2

What is it?

What does this type increased the risk of?

Rx?

A

Constant PR interval but intermittent failure to transmit to ventricles

High risk of progression to 3rd degree block so often requires pacemaker Rx

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12
Q

3rd degree HB - Complete HB

What is it?

What happens to the QRS?

Rx?

How can an MI of the RIGHT CORONAY ARTERY cause this?

A

No transmission of p waves in ventricles with a ventricular escape rhythm taking over

QRS is usually wider but can be narrow if Bundle of His takes over as pacemaker

Requires pacemaker

The AVN is supplied by the posterior interventricular artery, which in the majority of patients is a branch of the right coronary artery.

In the remainder of patients the posterior interventricular artery is supplied by the left circumflex artery.

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13
Q

QRS complex:

What is classed as a narrow QRS?

What is classed as a wide QRS?

QRS is classed as tall if the are > 5mm in the limb leads AND > 10mm in the chest leads.

What does tall QRS’s suggest?

A

<0.12 seconds

> 0.12 seconds

Hypertrophy

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14
Q

QRS complex:

What is a delta wave?

A

The ventricles are being activated earlier than normal from a point distant to the AV node.

The early activation then spreads slowly across the myocardium causing the slurred upstroke of the QRS complex.

Note – the presence of a delta wave does NOT diagnose Wolff-Parkinson-White syndrome. This requires evidence of tachyarrhythmias AND a delta wave.

https://geekymedics.com/how-to-read-an-ecg/

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15
Q

QRS complex:

A pathological Q wave is > 25% the size of the R wave that follows it or > 2mm in height and > 40ms in width.

What does a pathological Q wave suggest?

What wave of the Q, R and S should become bigger as you go from lead V1 to V6?

If this increase is not seen, what does it suggest?

A

Previous MI

R should become bigger - so negative to positive

Previous MI

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16
Q

QRS complex:

The J point is where the S wave joins the ST segment.

This point can be elevated resulting in the ST segment that follows it also being raised (this is known as “high take-off”).

High take-off (or benign early repolarisation to give its full title) is a normal variant that causes a lot of angst and confusion as it LOOKS like ST elevation.

How would you know it is not a STEMI?

High take off occurs mostly under the age of 50 (over the age of 50, ischaemia is more common and should be suspected first).

A

Typically, the J point is raised with widespread ST elevation in multiple territories making ischaemia less likely.

The ECG abnormalities DO NOT CHANGE! During a STEMI, the changes will evolve – in benign early repolarisation, they will remain the same.

The T waves are also raised (in contrast to a STEMI where the T wave remains the same size and the ST segment is raised).

https://geekymedics.com/how-to-read-an-ecg/

Read section on this

17
Q

Key points for assessing the J point segment:

Benign early repolarisation occurs mostly under the age of 50 (over the age of 50, ischaemia is more common and should be suspected first).

Typically, the J point is raised with widespread ST elevation in multiple territories making ischaemia less likely.

The T waves are also raised (in contrast to a STEMI where the T wave remains the same size and the ST segment is raised).

The ECG abnormalities do not change! During a STEMI, the changes will evolve – in benign early repolarisation, they will remain the same.

A

Key points for assessing the J point segment:

Benign early repolarisation occurs mostly under the age of 50 (over the age of 50, ischaemia is more common and should be suspected first).

Typically, the J point is raised with widespread ST elevation in multiple territories making ischaemia less likely.

The T waves are also raised (in contrast to a STEMI where the T wave remains the same size and the ST segment is raised).

The ECG abnormalities do not change! During a STEMI, the changes will evolve – in benign early repolarisation, they will remain the same.

18
Q

ST-segment:

It is normally meant to be an isoelectric line. What does it mean?

ST-elevation is significant when it is greater than 1 mm (1 small square) in 2 or more contiguous limb leads or >2mm in 2 or more chest leads.

What does ST-elevation suggest?

ST depression is ≥ 0.5 mm in ≥ 2 contiguous leads. What does ST depression suggest?

A

Neither elevated nor depressed

Acute full thickness MI

Ischaemia

When remembering measurements, remember that chest leads are always double number of mm compared to the limb leads as they are closer to the heart.

19
Q

T waves:

What are T waves representing?

T waves are classed as tall if the are > 5mm in the limb leads AND > 10mm in the chest leads (same as QRS).

What does tall T waves suggest? - 2

A

Repolarisation of ventricles

Hyperkalaemia - tall tented T waves
Hyperacute STEMI

20
Q

T waves:

In what limb lead AND in what chest lead is T wave inversion normal?

What drug toxicity closes T wave inversion?

A

Lead III and V1 - they are on the right side so more likely to be negative.

T wave inversion is a non-specific sign for a variety of conditions:

  • 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

Digoxin toxicity - at high doses

21
Q

T waves:

Biphasic T wave:

What is it?

Ischaemia is a cause.

What electrolyte imbalance cause this?

A

There are 2 peaks basically

Hypokalaemia

22
Q

Supraventricular rhythm

What is it?

4 types - name them?

What would you see on the ECG?

A

Abnormally fast heart rhythm arising from improper electrical activity in the upper part of the heart.

Atrial fibrillation
Paroxysmal supraventricular tachycardia (PSVT)
Atrial flutter
Wolff–Parkinson–White syndrome

Narrow QRS complexes
Inverted - ectopic atrial tachycardia
Varying morphology
Sawtooth - AF

23
Q

Ventricular rhythm

What is the cause of this? - 1

What do you see on ECG? - 1

What could happen to the p-waves?

A

Complete heart block

Wide/broad QRS

P waves and QRS at different rates so p-waves are often hidden behind QRS complexes.

24
Q

What effect does digoxin have on ECG’s

A

T wave inversion if it reaches toxic levels

25
Q

Effect of hypokalaemia?

Effects of hyperkalaemia? - 3

A

Flattened T waves

U wave at end of T wave

-------
Small P waves 
Wide QRS waves 
Tall tented T waves
Go to clinical chemistry for more detail!
26
Q

Effects of hypermagnesemia

Effects of hypocalcaemia? QRS, PR

Effects of hypercalcaemia? QT

A

Same as potassium

Widened QRS complexes
Prolonged PR intervals

Prolonged QT interval
Shortened QT interval

Go to clinical chemistry for more detail!

CARDIOLOGY (36 decks)

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