CV disease - other species

Question 1

What is an SV wave on an ECG?

Answer 1

Due to depolarisation of the sinus venosus which precedes the depolarisation of the atria (p wave). The sinus venosus is found in snakes.

Question 2

Describe snake hearts

Answer 2

3 chambers - R and L atria and one ventricle with internal ridges that allow considerable functional separation between oxygenated and deoxygenated blood.

Question 3

How does the canine heart impulse spread?

Answer 3

From endocardium –> myocardium to epicardium

As a single wave from a single focus

Question 4

Describe equine vector of cardiac depolarisation.

Answer 4

Different to a dogs.
Depolarisation spreads out from numerous foci due to the penetration of the Purkinje fibres in the ventricular myocardium.

Question 5

Is it normal for the time to be labile between T wave and QRS to be variable?

Answer 5

Yes - horses

No - human, ox, swine, sheep

Question 6

How do you position a rabbit for an ECG?

Answer 6

Sternal recumbency (don’t tolerate lateral)

Question 7

Where is the snake heart located?

Answer 7

Between 1/5 and 1/3 way down the body from the head.

Question 8

Describe the ultrasound set up for large animals

Answer 8

Low frequency and low frame rates and vice versa for small animals

Question 9

What are the challenges of ECG in exotics?

Answer 9

High HR - need high frame rate
Small hearts - high frequency transducer (good resolution)
Large hearts - low frequency transducer with good depth of field for good penetration (horse - 30cm)

Question 10

Outline ECG in exotics

Answer 10

Can be performed on almost any species

Differences in the way the chambers depolarise and repolarise

Question 11

How do small mammal ECGs appear?

Answer 11

high HR complexes will appear more spread out when the paper speed of the machine is increased.

Question 12

Outline echocardiography of exotics

Answer 12

Performed in many species (restraint, sedation, GA)
Can only be performed through soft tissue
Heart can only be viewed when in direct contact with body wall or through other organs that are in direct contact witht he body wall.

Question 13

Best method to do avian echocardiography = ?

Answer 13

trans-hepatic, sub-costal view

Question 14

What do high frequency ultrasound transducers provide good images of?

Answer 14

good images of structures near to the transducer but are not good for imaging large structures.

Question 15

Why might exotic species’ right chambers be enlarged? 2

Answer 15

If they are adapted for living at altitude or diving.

Question 16

What nutritional deficiency can cause an acquired heart disease in rabbits and mice?

Answer 16

Vitamin E deficiency

Question 17

What protozoal infection causes myocarditis in rabbits?

Answer 17

Encephalitozoon cuniculi

Question 18

Name a drug which can cause a toxic acquired cardiac disease

Answer 18

Doxorubicin - toxic to rabbits, rat, mice, dogs, pigs

Question 19

List some frequently used cardiac disease drugs

Answer 19

FUROSEMIDE (small mammals)
ACEI
Anti-arrhythmics
Beta-blockers
Pimobendan (rats, ferrets and rabbits)

Question 20

List some general rules for approaching cardiac disease in unusual species. 8

Answer 20

Evidence of cardiac disease?
Differential diagnoses?
Signs of HF?
Signs of CV abnormality? (murmur, rhythm disturbance)
Knowledge of cardiac disease in this species? Prone?
Diagnostics methods?
How to distinguish normal and abnormal?
Similar species?