Equine Cardiac examination Refresher and Murmurs Flashcards
How does cardiac disease most commonly present in horses?
- Incidental e.g. pre-purchase exam
- History of poor performance
- Systemically ill horse
- Horse presented with evidence of heart failure (rare)
What are the aims of investigation when investigating cardiac disease in horses?
Need to establish significance of any findings:
- Cardiac murmurs/dysrhythmias are COMMON
- Significance for performance?
- Collapse?
- Progression?
- Interpret in context of use/intended use of horse
Describe how to auscultate a horses heart
- Quiet environment
- Take time
- Let horse settle
- Get into the rhythm
Listening on the RHS:
- Pull leg forward
- Stick stethoscope bell right under triceps just dorsal to point of elbow
The apex beat in horses correlates to which valve?
Mitral
Name the valve that lies between the right atrium and ventricles
Tricuspid valve
Name the valve that lies between the left atrium and ventricles
Mitral
Systole = ?
Diastole = ?
Systole = contraction
Diastole = relaxation
Describe the S1 and S2 heart sounds
Ventricles contract:
- S1 : Shutting of AV valves (Mitral/tricuspid)
- “ LUB “
Ventricles relax
- S2 : Shutting of Semilunar valves (Aortic/Pulmonic)
- “ DUP “
Describe the other heart sounds heard in a horse
S4: atrial contraction
- “ B “ Very common
- Just before S1
S3: end of rapid ventricular filling
- “ D “ Less common
- Just after S2
How does mitral valve regurgitation affect the heart sounds in horses?
Causes a loud S3 due to lots of blood going back into the atrium, it is now full of blood, when the ventricle relaxes lots of blood rushes in, causing a loud sound
Describe which heart sounds are loudest in the basal and apical areas of the heart
Basal - S1 quieter, S2 louder
Apical - S1 louder, S2 quieter
Describe the lengths of systole and diastole in the normal heart - normal HR
Systole is much shorter than diastole
Describe the lengths of systole and diastole in the normal heart - high HR
Duration of systole = Duration of diastole
What is a murmur?
Turbulence of blood flow
Reynolds number influences?
Turbulence
Describe the sound made by normal laminar flow of blood
None - silent
Which factors influence turbulence of blood?
Stenosis of a vessel
Valve regurgitation
Increased blood flow