ECG

Question 1

What 3 ways can you work out mean electrical axis??

Answer 1

Biggest QRS complex - is this pos or neg- read the value

Quadrant - use 1 and AVF- draw lines if pos or neg

Isoelectric lead- which is most simpler up and down, which is perp to this- is this mostly pos or neg- read the value

Question 2

How does an ECG show a vector

Answer 2

Vector has direction and magnitude

Direction shown as whether positive or negative deflection (if positive moving towards the positive electrode)

Size of deflection is effected by the amount of tissue.
When comparing leads, the biggest deflection is shown on the lead most parallel to the overall vector of the heart- which is mostly lead 2

Question 3

If a patient has these what could it mean?

Left axis deviation

Right axis deviation

Answer 3

Left ventricular hypertrophy

Right ventricular hypertrophy

Question 4

What other things could an MEA outwith ranges mean??

Answer 4

Heart isn’t sitting in normal position in chest

Conduction pathway is abnormal (e.g. Bundle blockage)

Question 5

Why do we called premature complexes premature complexes

Answer 5

Because they are formed to when the heart shouldn’t be depolarising

Question 6

What would you see with a supra ventricular or junctional Premature complex

Answer 6

Normal QRS complex (sharp point up)

No P wave (atrias didn’t depolarised properly)

Question 7

What would you see with a ventricular premature complex

Answer 7

Wider QRS complex
Upside down (sharp spike down)
AP not followed normal direction of travel
No p wave as atria not involved in AP
Always have large T wave opposite to QRS

Question 8

What do we call runs of these premature complexes

Answer 8

Supra ventricular or ventricular tachycardia

Question 9

When is AF seen

What does it look like on the ECG

Answer 9

Animals with large atria (stretched or normal horses just with huge atria)

On ECG see irregular RR intervals, supra ventricular tachycardia.

Question 10

What does AV block cause

Answer 10

Bradycardia

Question 11

How do you differentiate between first second and third degree AV block

Answer 11

1 - PR interval prolonged

2 - mobitz 1 or 2: 1= progressive lengthening of PR interval until one suddenly doesn’t form. 2= no lengthening all the same then suddenly one doesn’t form (p wave but no QRS following)

3 - P and QRS have no relation to eachother because SAN controlling atria and AV takes over ventricles