Equine Cardiology: Diagnostic Approach Flashcards
In a horse, when would cardiac insufficiency be must detectable?
During maximum performance
What is the resting HR of a horse?
Around 40bpm
What is the maximum HR of a horse?
220bpm
How might cardiac disease present in a horse?
- History of poor performance
- Clinical signs of cardiac failure (rare)
- Systemic illness
- Incidental finding
Give examples of tools of investigation for cardiac abnormalities?
- Clinical Examination / Auscultation
- ECG +/- exercise and 24-hour
- Echocardiography
- Clinical pathology
- Exercise testing
How can anaemia lead to a cardiac abnormality?
Anaemia is a common paraneoplastic effect -> turbulence due to reduced viscosity of blood -> murmur
Where is it easiest to feel a peripheral arterial pulse in a horse?
Facial artery
Jugular distention is a sign of?
Right sided HF
Give examples of what would be assessed on a clinical exam?
o Respiratory Rate o Peripheral oedema o Mucous membranes o Hydration status o Peripheral perfusion (dilation of peripheral veins can show occlusion e.g. of the vena cava) o Heart rate and rhythm
What factors can influence HR?
Temperature
Stress
Metabolic state
Where do you auscultate a horse to listen to the heart?
- Apex beat = mitral valve: start here on the LHS
- Move the stethoscope dorsally and cranially to cover the cardiac window
How do you listen to the heart on the RHS of a horse?
- Pull leg forward
- Stick stethoscope bell right under triceps just dorsal to point of elbow
- Very small cardiac window on the right (highlighted in red)
Describe the position of the valves within the heart
RA-RV = Tricuspid valve
RV-Pulmonary artery = pulmonic valve
LA-LV = Mitral valve
LV-Aorta = Aortic valve
Describe the basics of systole and diastole
Systole – mitral and tricuspid valves close = CONTRACTION
Diastole – pulmonic and aortic valves close = RELAXATION
The sounds S1 and S2 are created by?
S1 = Shutting of the mitral and tricuspid valves S2 = Shutting of the aortic and pulmonic valves
The sounds S3 and S4 are created by?
S3 = atrial contraction S4 = End of rapid ventricular filling
When are S3 and S4 heard?
S3 = just before S1
S4 = just after S2
4, 1, 2, 3 order
Which is shorter at rest, systole or diastole?
Systole
Which is shorter when the heart rate is high, systole or diastole?
Their lengths are equal
Name a cardiac biomarker and what does it indicate?
Cardiac troponin - indicates myocardial disease
Where is equine ECG indicated?
- Suspected non-physiological arrhythmia detected
- Chamber dilation on echocardiography
- Poor performance
- Monitoring of patients with CVS compromise e.g. systemically ill, under anaesthesia
How does S4 appear on the ECG?
As the P wave - atrial depolarization and contraction
