Equine Cardiac Murmurs Flashcards
What are 2 types of endocardial disease?
Endocardiosis
Endocarditis
What is endocardiosis?
Valvular degeneration - progressive
Mitral, aortic or tricuspid valves
What is endocarditis?
What can it cause it cattle and equine?
- Bacterial in origin secondary to bacteraemia
- uncommon but is important in all species
- Cattle: Liver abscess, TRP, mastitis
- Equine: Dental, respiratory, thrombophlebitis
- Other causes
- Valve dysplasia
- Valvulitis
- Valve prolapse
- Ruptured chordae tendinae
What are clinical signs of bacterial endocarditis?
- Acute onset Congestive heart failure
- Fever, cardiac murmur, tachycardia, tachypnoea
What do you see on laboratory data with bacterial endocarditis?
- Hyperfibrinogenaemia, anaemia and leucocytosis
- Blood culture
- Repeat x3 (false negatives) ideally when pyrexic
- Sterile procedure (do not use indwelling catheter)
What are some common differentials for a systolic murmur on the LEFT hand side?
- Between S1 and S2 if in systole
- Mitral loudest just behind tripces
- Further forwards underneath triceps – aortic flow, potentially pulmonic
- Most flow murmurs are related to LHS ejection, just because pressures higher
- Cannot differentiate aortic from pulmonic just from stethoscope
- There will be horses with both – flow murmurs and regurgitation
If you have a murmur IN SYSTOLE, when would you hear it?
Between S1 and S2
Where would a mitral valve be loudest?
LHS
Just behind triceps
Where would aortic flow murmur be heard loudest?
Can you tell this from a pulmonic flow murmur?
- Further forwards underneath triceps – aortic flow, potentially pulmonic
- Cannot differentiate aortic from pulmonic just from stethoscope
12 year old polo pony, Male, 470kg
Presents with a recent onset depression and poor performance.
The following is audible on the left side over the 5th intercostal space
- What is a likely diagnosis based on where it can be heard?
- Could the murmur you pick caused the clinical signs?
As its in the 5th intercostal space. 12 year old horse, MR – its very common! Most likely to result in clinical signs, not because they go into CHF, but because it causes LA enlargement and predisposes them to atrial fibrillation
What is the second most common form of valvular heart disease?
Mitral insufficiency
What iis the most common cause of clinical signs of cardiac disease?
Mitral insufficiency
Mitral insufficiency:
- What grades can it be?
- When will you hear it?
- What is its shape?
- Where is it loudest?
- How does it radiate?
- Grade: 1 – 6 /6
- Timing: Early, mid, holo, pan- systolic
- Shape: Band Shaped (if its deep crochendo, it gets quieter)
- Loudest: Left 5th intercostal space
- Radiates: Caudodorsally
- Move stethoscope in different areas to find where you can heart it
- MR- will go from apex to base, so this is the area that the jet will radiate
What can be some clinical signs of mitral insufficiency?
- Incidental finding
- Finding murmur on routine exam that is causing the horse no problems at all, not usually a problem
- Poor Performance
- Only because predisposes them to LA enlargement which they can then get atrial fibrillation
- Atrial fibrillation
- left-sided failure (Acute onset)
- If acute onset Mitral valve disease e.g. caused by bacterial endocarditis – will go rapidly into LHS heart failure
- Right-sided failure – although uncommon, its more likely we will see this as we don’t really see LHS failure from the outside
- If progresses over months to years, this is the thing we will recognise
- Peripheral oedema, jugular pulsation (if LHS failure – pulmonary oedema) – can see the RHS things more than the LHS things
Collapse, fainting or sudden death
How does mitral insufficiency progress?
Mitral Regurgitation
- regurgitant jet, more blood from LV to LA during ventricular systole, although slight reduction in CO – rarely cases clinical signs. Get LA enlargement as a result, so during diastole, more blood in atria, so therefore LV gets enlarged as well – and the 3rd heart sound will become a lot louder. If MR plus a loud 3rd heart sound – POOR PROGNOSIS
- Diastole - Increased ventricular filling. Loud third heart sound
- Systole - Increased ventricular work will increase the regurgitant fraction. Left Atrial enlargement > AF
- More blood in LA in systole than normally, get back flow through blood through into lungs so get pulmonary artery hypertension –> increased pressure on vascular pulmonary arteries, this is the weak point in horses CVS – this is the point that can rupture
If pulmonary arteries are enlarged, what should happen to the horse?
If pulmonary arteries enlarged, horse should retire as a number of them can rupture pulmonary artery at exercise, collapse and die
If pulmonary artery is bigger than aorta, what should you suggest for the horse?
If PA bigger than aorta, has hypertension, recommend this horse stops work
What are these 3 arrows pointing to on this echo?
What should happen to this horse?
This horse have severe MR
Top arrow - right artrium
Middle - aorta
Bottom - pulmonary artery
If PA bigger than aorta, has hypertension, recommend this horse stops work – they didn’t listen, horse died 6 months later
What are some indications for echocardiography in a horse with mitral regurgitation?
- Grade > 3/6
- Grade 3 or above – should undergo further examination
- Loud third heart sound
- Already know will have a big LA – should either undergo further exam or say do not ride this animal
- Resting tachycardia
- Suggests may have heart failure
- Fever
- Acute onset and related to fever – might be bacterial endocarditis
- Poor performance
- Arrhythmias
What is a physiological flow murmur?
Innocent heart murmurs are harmless sounds made by the blood circulating normally through the heart’s chambers and valves or through blood vessels near the heart