Equine Cardiology Flashcards
What is the order of heart sounds?
S3: Rapid filling of ventricles
S4: Atrial contraction
S1: AV valves close (Lub)
S2: Aortic/pulmonary valves close (Dup)
Which heart sounds can be heart in the horse normally?
All of them, S3 is less commonly heard
What are the two types of physiological murmurs?
Aortic flow
Ventricular filling
Where is an aortic flow murmur heard?
What sound is it?
When does it finish?
Is is systolic or diastolic?
Left heart base
Crescendo-decrescendo
Always finish before S2
Systolic
What type of horses do you hear ventricular filling murmurs in?
What heart sounds are they between?
What sound would you expect?
Young, fit horses
Between S2 and S3
Squeak/whoop/click
Diastolic
Where is the PMI in mitral valve regurgitation murmurs?
Is it during systole or diastole?
Left heart apex
Holo/pansystolic
On which side do you hear VSD murmurs?
Systolic or diastolic?
Right (loud - thrill)
Pansystolic
Where is the PMI for aortic regurgitation murmurs?
Are they diastolic or systolic?
What is their characteristic sound, and age of presentation?
PMI: Heart base Holodiastolic Uhhhhhh "Teenager murmur" Decresendo, buzzing/cooing (older horses, teens and above)
What is the classic sound of a PDA murmur?
Where is the PMI?
Waxing/waning “machinery murmur”
Left heart base
What are the 3 distributions of oedema?
- Dependent (lowermost parts of body)
- Local
- Anasarca (generalised subcutaneous oedema)
What are the 4 mechanisms of oedema?
- Increased hydrostatic pressure
- Decreased colloid osmotic pressure (COP)
- Lymphatic obstruction
- Increased capillary permeability
What does Equine Viral Arteritis (EVA) cause?
What are the main
What do you do if you have a suspected case?
(Pan)vasculitis
Variable clinical signs:
Oedema, abortion, respiratory disease, dull/pyrexic
NOTIFIABLE - report to DEFRA!
How is Equine Viral Arteritis (EVA) spread?
Respiratory or venereal (carrier stallions)
What are two diseases causing vasculitis that are notifiable to DEFRA?
Equine Viral Arteritis
African Horse Sickness
What is the difference between Type 1 and 3 hypersensitivity?
Type 1: Histamine
Type 2: Immune complex
What can jugular catheters cause?
Which is more thrombogenic, Polyurethane/silicon or teflon?
Thrombosis, thrombophlebitis (thrombosis secondary to inflammation of vessel wall)
Teflon is more thrombogenic
What is the differential diagnosis for lymphangitis?
Septic synovitis
Where is the left and right arm and neutral leads located in an equine ECG?
Left arm (+) Heart apex Right arm (-) Mid right jugular furrow Neutral Remote from heart
Which AV block is normal in horses? What is it caused by?
2nd degree
Increased vagal tone (decreases HR)
What is sinus arrhythmia?
What does it NOT indicate?
Periodic waxing and waning of R-R interval
NOT in heart failure
What type of rhythm does atrial fibrillation cause?
Which heart sound might it cause to be prominent?
What heart sound might you not hear?
Irregularly irregular
S3 (Ventricular filling)
S4 (Atrial contraction)
What cardiac pathology can Atrial Fibrillation be secondary to, and why?
Mitral valve regurgitation
Due to causing left atrial dilation
What is the re-entry mechanism of Atrial Fibrillation?
Sustained by:
Large atrial mass
Variable refractoriness of cells (due to high vagal tone)
What are 3 signs of heart failure in the horse?
Can these be caused by Atrial Fibrilation?
- Peripheral oedema
- HR > 50bpm
- Jugular distension/pulsation
AF is NOT a sign of heart failure, look for other underlying causes
