Cardiovascular: ECGs & Arrhythmia

Question 1

What are the 6 leads in the coronal plane?

Answer 1

The limb leads
* aVR
* aVL
* aVF
* I
* II
* III

Question 2

What are the 6 leads in the transverse plane?

Answer 2

The chest leads

V1-V6

Question 3

Describe the colour of the limb electrodes

Answer 3

Right shouder - Red
Left shoulder - Yellow
Left leg - Green
Right leg - Black

Hint: start with red for right then work through the traffic lights clockwise

Question 4

Where do each of the coronal leads lie on the QRS axis?

Answer 4

• I: 0’
• II: +30’
• aVF: +90’
• III: +120’
• aVR: -150’
• aVL: -30’

Question 5

What is the normal QRS axis range, and what defines a left axis deviation and a right axis deviation?

Answer 5

Normal: -30’ - +90’
RAD: +90’ - +180’
LAD: -30’ - -90’

This is because the wave of propagation normally goes from SA node through bundle of hiss and down in right-left downward direction.

Question 6

How would you use a QRS deflection in leads I,II&III to calculation deviation?

Answer 6

Question 7

Is there any axis deviation here?

Answer 7

No, I&II are positive deflection and III is negative, this is normal QRS axis

Question 8

Is there any axis deviation here?

Answer 8

Yes, I is positive deflection and II&III are negative, this is therefore a left axis deviation

Question 9

Is there any axis deviation here?

Answer 9

Yes, II&III are positive deflection and I is negative, this is therefore a right axis deviation

Question 10

What does the P wave correspond to?

With regards to electrical conduction

Answer 10

Atrial depolarisation

Question 11

What does the QRS complex correspond to?

With regards to electrical conduction

Answer 11

Ventricular depolarisation

Question 12

What does the T wave correspond to?

With regards to electrical conduction

Answer 12

Ventricular repolarisation

Question 13

What does the PR segment tell us about with regards to electrical conduction?

What does deviations in a PR segment therefore hint at?

Answer 13

If P is depolarisation of the atria and QRS is depolarisation of the ventricles then PR segment is the conduction through the AVN/ bundle of hiss.

A prolonged PR segment can indicate conductive tissue dissorder

A shortened PR can indicate that conduction is bypassing the AVN

Question 14

What does the QRS complex tell us about with regards to electrical conduction?

What does deviations in QRS complex therefore hint at?

Answer 14

Time for ventricular depolarisation

Deviations can indicate conductive tissue dissorders in the ventricles such as right bundle branch block or left bundle branch block

Question 16

What does the ST segment tell us about with regards to electrical conduction?

What does deviations in a ST segment therefore hint at?

Answer 16

ST segment – start of
ventricular repolarisation
(should be isoelectric aka flat)

ST elevation acute infarction

ST depression ischaemia

Question 17

What does the T wave tell us about with regards to electrical conduction?

Answer 17

Ventricular repolarisation

Question 18

What time is one small box equivelent to?

Answer 18

0.04s

Question 19

What is Wolff-Parkinson-White (WPW) syndrome?

Answer 19

A syndrome that causes the an extra path of conduction in the heart bypassing the AV node and is more rapid that AV/bundle of hiss conduction

Question 20

What is this hinting at?

Answer 20

Wolff-Parkinson-White (WPW) syndrome

Shorter PR interval therefore AV node being bypassed

Question 21

Why could Wolff-Parkinson-White (WPW) syndrome make AF worse?

Answer 21

If conduction between atria and ventricles bypassed and rapid conduction then AF could also lead to VF

Question 22

What is this hinting at?

Answer 22

Left ventricular hypertrophy due to high blood pressure

QRS complex phatty on leads V5&V6 corresponding to depolarisation of a large muscle where the left ventricle is. Corresponding negative reflection on the opposite leads

Question 23

What is this hinting at?

Answer 23

RSR in V1 is Right bundle branch block

Question 24

What is this hinting at?

Answer 24

Left bundle branch block

Question 25

Anything up here?

Answer 25

Nope P wave is followed by a regular PR interval and QRS complex followed by a regular T wave The change in rate is due to breathing, speeds up when you breath in, slows down when you breath out

Question 26

What is this?

Answer 26

Sinus tachycardia Increased heart rate however the increased rate is still coming from regular sinus node signalling therefore sinus tachycardia

Question 27

What is up here?

Answer 27

Sinus bradycardia

Question 28

What is sino-atrial disease

Answer 28

A degenerative condition affecting the atria, including the sinoatrial (SA) and atrioventricular (AV) nodes Can lead to sinus tachycardia, sinus bradycardia, atrial ‘ectopic’ beats, and atrial fibrillation

Question 29

What is this?

Answer 29

Atrial tachycardia QRS doesn't always follow P wave meaning somewhere in the atria is fireing itself A consequence of sino-atrial disease

Question 30

Sino-atrial disease - treatment?

Answer 30

permanent pacemaker to prevent slow rhythms antiarrhythmic drugs to prevent or moderate rapid rhythms – beta blocker – digoxin – amiodarone

Question 31

What is this?

Answer 31

1st degree AV block PR interval extended indicating a delayed conduction time between atria and ventricles

Question 32

What is this?

Answer 32

2nd degree AV block Blockage at bundle of hiss Some QRS complexes not fireing at all If QRS doesn't fire to long enough then results in passing out

Question 33

What is this?

Answer 33

3rd degree AV block P waves completely independent of ventricular depolarisation, none are getting through Ventricles still contract on their own rythm as a backup but it is not ideal

Question 34

Causes of AV nodal block

Answer 34

* sino-atrial disease * coronary heart disease * aortic valve disease * damage during heart surgery * drugs – beta-blockers – digoxin – calcium channel blockers

Question 35

What is this?

Answer 35

Atrial fibrillation Atria activating rapidly therefore they can't contract effectively (contractions can't keep up with signals) Can also appear on some leads as no P-wave present at all, just flat between each QRS complex with T wave

Question 36

What is this?

Answer 36

Atrial flutter Saw tooth - atrial flutter Signal keeps going around atria triggering itself rapidly rather than moving down the atria

Question 37

Different look of atrial fibrillation vs atrial flutter?

Answer 37

Atrial fibrillation - messy Atrial flutter - sawtooth

Question 38

Causes of atrial flutter / fibrillation

Answer 38

* sino-atrial disease * coronary heart disease * valve disease (esp. mitral valve) * hypertension * cardiomyopathy * hyperthyroidism * pneumonia, lung pathology

Question 39

Treatments for atrial fibrillation/ atrial flutter

Answer 39

* drugs to block AV node and therefore limit heart rate – digoxin – beta blocker – calcium channel blocker * electrical cardioversion * catheter ablation

Question 40

What arrythmia could childhood pneumonia lead to?

Answer 40

Atrial fibrillation/ flutter Untreated strep as a child can cause a mumour as a child which then makes the atria weakened and the damage effects kick in later in life

Question 41

What is this?

Answer 41

Ventricular tachycardia Short circuiting of impulses within ventricles - signal going round and round ventricles. Diseased ventricles No p wave - qrs firing on its ones

Question 42

What is this?

Answer 42

Ventricular fibrillation Carnage Heart can't really function

Question 43

Treatment for ventricular fibrillation

Answer 43

ACUTE * defibrillation * IV antiarrhythmic drugs * remove any triggering cause LONG TERM * oral antiarrhythmic drugs * treat underlying heart conditions * implantable defibrillator for some patients