Equine cardiology

Question 1

Describe the four heart sounds of the horse

Answer 1

S1 - AV valve shutting

S2 - Semilunar valve shutting

S3 (after S2) - End of rapid ventricular filling

S4 (before S1) - atrial contraction

Question 2

How does the heart rate/ contraction change with exercise?

Answer 2

Heart rate increases but also of note is that diastole shortens

Question 3

Where on the horse would ECG leads be ideally placed?

Answer 3

1. Right jugular groove 1/3 up the neck
2. Left thorax over the apex beat
3. Withers

Question 4

What is the difference between holo and pansystolic?

Answer 4

Holo - can still hear heart sounds

Pan - obliterated heart sounds

Question 5

PMI

Answer 5

Point of Maximal Intensity (localising heart murmurs)

Question 6

Describe an aortic flow murmur.

What is the cause of them?

Answer 6

Aortic flow murmurs are caused by turbulence through a large tube.

• Early-mid systole
• Holo, early, mid or late systole
• Localised over the heart base
• Changed intensity with heart rate
• Crescendo-decrescendo

Question 7

What is the cause of a filling murmur?

Describe the nature of one.

Answer 7

Filling murmurs are caused by ventricular tubulence

• Early diastole
• Squeak sound
• PMI over heart base/ apex

Question 8

What is the cause of a pathological murmur?

Answer 8

Caused by valvular regurgitation and congenital defects.

Question 9

Describe this ecg

Answer 9

Abscent p waves

Fibrillating baseline

Normal qrs

Irregular r-r intervals

Afib!

Question 10

Describe this ecg

Answer 10

Pause between r-r occasionally

No p waves

Sinus block/ arrest

Question 11

What drug can be used to induce pharmacological cardioversion?

Answer 11

Quinidine sulphate

(every 2 hours until conversion and then every 6 hours)

Question 12

What are the four main mechanisms of oedema?

Answer 12

1. Increased hydrostatic pressure
2. Decreased oncotic pressure
3. Decreased lymphatic drainage
4. Increased capillary permeability

Question 13

What are the most likely pathological outcomes from each of the mechanisms of oedema?

Answer 13

1. HSP - congestive heart failure
2. COP - hypoproteinaemia (liver, nutrition, kidney)
3. L - lymphangitis
4. IN - vasculitis

Question 14

What cause of infectious vasculitis is a venereal pathogen?

What differentials may be expected?

Answer 14

Equine viral arteritis

Differentials: EHV1, EIA, Hendra, AIHS

Question 15

What clinical signs may be expected of an aorto-iliac thrombosis

Answer 15

Lameness

HL pain

Can be felt on rectal exam

Question 16

What type of catheter is most likely to cause a jugular thrombosis?

Answer 16

Teflow > polyurethan/ silicon

Question 17

What treatment protocol should be explored with a case of lymphangits?

Answer 17

• Anti-inflammatory - flunixin/ dex
• Antimicrobials - broad spec (TMPS, penicillin, doxy)
• Topical cleaning
• Cold
• Exercise
• Tetanus prophy