Equine Poor Performance and Cardiac Disease Flashcards
What is poor performance?
Horse not performing as well as owner wants it to… not to owners expectations
Physical exam – would expect to find not much at rest? Largely often have an animal that is normal or nearly normal at rest and only develops disease at exercise (not all cases, but a lot)
What are the top 5 causes (body systems) of poor performance in horses?
•1. Musculoskeletal abnormalities
–Can look sound with bilateral hind limb lameness
•2. Respiratory abnormalities
–LRT abnormalities, then URT abnormalities.
Sub clinical myopathies somewhere between these 2 systems
•3. Cardiac abnormalities
–Dysrhythmias – murmurs on their own DO NOT CAUSE POOR PERFORMANCE UNLESS IN HF WHERE IT WILL BE SICK AT REST
- Neurological abnormalities
- Other causes
- NB – MULTIPLE CONCURRENT ABNORMALITIES ARE VERY COMMON ESP 1-3.
- Gastric disease is not on this list as doesn’t cause poor performance much!!
When doing a respiratory exam in a horse with poor performance, what should you listen to and check etc?
- Auscultation
- Get resp rate
- Re-breathing examination at rest
- Listen for respiratory noise at exercise
- Tracheal wash/BAL
–Looking for lower airway disease
•Resting endoscopy
–To see if we can see anything or URT – look for sub epiglottic cysts, DDSP, or epiglottic entrapments etc.
•Endoscopy at exercise
–Treadmill or Overground
–Once decided not lame
When doing a cardiac exam in a horse with poor performance, what should you listen to and check etc?
•Pulse quality and rate
–At rest
•Jugular filling and pulsation
–Should only fill and fall in distal third of the neck
- Cardiac evaluation – left and right sides
- Resting ECG and echocardiography
–If we have reason to do this such as a murmur
- Exercising ECG
- Echocardiography following exercise when HR increased (>100 BPM)
- (Stress echocardiography using atropine and/or Cardiac isoenzymes if you suspect myocardial disease)
When doing a lameness exam in a horse with poor performance, what should you listen to and check etc?
–Straight line on hard
–Lunged on hard and soft (if appropriate)
–Ridden
–Flexion tests
–Nerve blocks
–Rectal examination
•Looking for thrombi on internal iliac arteries, usually as a result of Strongyle migration – not for every horse but might be important in some!
–Trying to rule out bilateral hindlimb lameness
A 7 year NH horse is presented for poor performance of 4 weeks duration, although the trainer reports its form has reduced over the last 6 months. The jockey reports that the horse gurgles just prior to a reduction in performance at speed and when racing
- TPR=37.5oC, Pulse=28BPM, RR=10BPM
- On physical examination the horse has pink MM with a CRT < 2seconds, no jugular pulses, II/VI holosystolic decrescendo, PMI on Left side
- Respiratory examination
–Mild tracheal rattle, but NAD on thoracic auscultation and with a re-breathing examination
- Give some differentials diagnoses for this murmur
- Could it be significant to this animals performance?
- What will you do next?
- DD?
(Outcome included on answer slide. Lecture was difficult to write up into FC as all cases - so these best for read throuhg and thought would be best to do each case on just one FC, so sorry they long - but will get more from it for reading it etc)
•What are the differential diagnoses for this murmur?
–Mitral regurgitation however decrescendo is a less common shape for this
–Physiologic flow murmur – most likely
•Could it be significant to this animal’s performance?
–If it was MR – no, it could not cause it
–It isn’t in HF as HR is normal! Would expect 60 or above it was in HF at rest (unless silly naughty ones etc.)
•What are you going to do next?
–Endoscopy
–Has mucus – the rattle, might want to sample the mucus
–Snot at thoracic inlet – equine asthma (IAD most likely compared to RAO) – so best sample would be to take TTW or BAL. With IAD, the caudal dorsal lung field most likely to be diseases so do a BAL – using scope. Make sure we had ruled out and treated LRT disease
•What are your differential diagnoses?
–Tracheal rattle - IAD
–For gurgling – DDSP – so could over ground scope this horse, but try to put it off until sorted lower airway diseas
OUTCOME:
- Sorted LRT disease
- Started to gurgle again
- Did laser of the soft palate and went back to perform
- A 14 year old TBX horse presents with reported tiring at exercise – general purpose
- BCS=5/9
- No topline (muscle mass), epaxial muscles
- TPR=38.1oC, Pulse=36BPM RR=16BPM
- Cardiac exam
–IV/VI holosystolic plateau murmur PMI LICS5
–Normal pulse quality
•Resp exam
–Increased bronchovesicular sounds over the left and right hemithoraces
- What are some DD for the murmur?
- Could this be causing the horse tire?
- Could it lead to problems in the future?
- What are your DD overall?
- What further evaluations would you undertake in this animal?
•What are the differentials for this murmur?
–Mitral valve regurgitation – too loud to be physiological flow murmur
–Could be tricuspid very loud if sound came over to left, but would expect right side too
–HORSE IS NOT IN HF AS HR NORMAL
•Could they be causing the horse tire?
–What could be the sequalae to this regurg that might result in this horse becoming tired? ATRIAL FIBRILLATION. MR –> big LA –> predisposed to AF
•Could it lead to problems in the future?
–Definitely could if develops AF
–Could go into HF with MR – rare but happens
•What are your differential diagnoses?
–On respiratory exam – equine asthma, particularly RAO
•What further evaluations would you undertake in this animal?
–Exercise ECG? Gayle would echo him to see how big his heart was. If normal size, wouldn’t ECG him, but if it was big – would do ECG.
–To confirm diagnosis – most reliable test for identifying RAO – BAL. often blind, can do with endoscope.
–Trial therapy? Risks is that if it doesn’t work, can sometimes not have a baseline to go back to. Clenbutarol for asthma?
–If normal heart size and normal rhythm, this can continue ridden work as it usually develops slowl
OUTCOME
–Echo – normal size heart
–No exercise or resting ECG
–Did do a BAL – increased percentage of non degenerate neutrophils
–Treated with inhaled drug route – had previously received oral clenbuterol but had side effects of sweating etc. – so inhaled bromide and steroids for short while and did stuff with his management
–Managed to wean off drugs with improved management
- You are presented with a 20 year old retired showjumper that is now used for hacking and hunting
- A murmur and dysrhythmia were noted on auscultation when the horse was to be sedated for dental work
Physical exam
–BCS 4/9
–T=37.3oC
–P=28-36BPM
–R=12BPM
Cardiac exam
–Waterhammer pulses
•Bounding pulse suggests – aortic regurgitation. Tells us we have increase in SV likely to be associated with LV enlargement
–Irregular rhythm
–V/VI holodiastolic decrescendo murmur PMI LICS4
•Respiratory examination
–NAD on tracheal and thoracic auscultation with and without a re-breathing bag
•Lameness and neurological examination - NAD
- Based on the cardia and physical exam, what is it suggestive of?
- What are DD for differentials for the murmur and dysrhythmia
- Could it be reason for performance limiting?
- Further investigations?
- Suggestive of AORTIC REGURGITATION THAT HAS LEAD TO LV ENLRAGEMENET
What are your differentials for the murmur and dysrhythmia in this case?
–Irregular rhythm – second degree AV block or AF (could be VPCs but common things are common)
•Could they be performance limiting?
–If this horse is having lots of premature beats at exercise, could be associated with poor performance
–Dysrhtmymia could be associated with poor performance if it has AF
•What further investigations would you perform?
–Rest and exercise ECG and echo would be nice to see how big LV is but deal break is what the exercise ECG looks like
What is your interpretation of these findings from exercising ECGs?
Ventricular rhythm disturbance
Lots of VPCs and ventricular tachycardias
A 12 year old hunter presents with a 6 week history of poor performance and epistaxis. On auscultation, the only abnormality is a irregularly, irregular rhythm with 3 audible heart sounds
- What are the differential diagnoses for this finding?
- How can you further evaluate this?
- What would you recommend regarding treatment to the client?
- What are the differential diagnoses for this finding?
- EIPH
–If enough blood in trachea, an prevent further gas exchange in the lungs
- 2nd degree AV
- Atrial fib
- How can you further evaluate this?
–ECG it
–If 2nd degree av block then scope it and interested in a BAL, does it have inflammation in its lungs that’s resulting to its EIPH and therefore bleeding? Wouldn’t scope if find AF
•What would you recommend regarding treatment to the client?
–Probably do need to try and fix as not performing and nose bleeds at exercise and cannot hunt with AF
–Quinidine or DC cardioversion? Let them choose?
- Quinidine is likely to work as its been less than 3 months
- Offer both and let them choose
OUTCOME
- Did DV cardioversion
- Horse converted at 200 joules (low for a hunter)
- As a 9 month follow up was still in sinus rhythm
Describe findings of this ECG
Atrail fibrillation
Normal QRS complexes
No associated P waves, have F waves
Variable R to R interval
- A 5 year old Warmblood mare that has competed at novice level Eventing presents with lethargy and poor performance.
- On PE – HR=48bpm, RR=16 BPM and T=38.5oC
- Cardiac auscultation – grade III/VI holosystolic murmur PMI LICS5
- NAD on respiratory auscultation
- Fractional shortening=12%
- MR and TR
–Mitral and tricuspid regurg
•Increased LV Diameter in diastole
- What are your differentials for these findings and this murmurs?
- How would your further evaluate this case?
- Why does it have myocarditis and inflammatory profile with increase RR?
- What is your likely diagnosis? What further questions would you ask to try and ascertain the aetiology?
•What are your differentials for these findings and this murmur?
–Physical exam findings – temp a bit high (just in reference range, its unusual to have horses sitting up at this temperature). HR – little bit high, esp for warmblood. RR – slightly high.
–DD for murmur: MR and physiological aortic flow murmur
•How would you further evaluate this case?
–Could ECG – to see rhythm, had sinus tachycardia as baseline rhythm
–She is young – too young to have this murmur really
–Echoed it
•Poor fractional shortening – in a normal animal is around 30% and in this horse it was 12%. Valves NORMAL
–SUGGESTIVE OF MYOCARDITIS
–Haematology and acute phase proteins – measure fibrinogen and serum amyloid A in this case
- Showed high fibrinogen and high serum amyloid A and high WBC mainly neutrophils
- Why does it have myocarditis and inflammatory profile with increase RR?
–Streptococcal infection? These likely to be in LNs and in LRT – this horse could have pneumonia or it could have INFLUENZA! Normally horses have influenza have temps closer to 40
•What is your likely diagnosis? What further questions would you ask to try and ascertain the aetiology?
–Myocarditis
–Scoped and tracheal wash
–Cultured degenerated neutrophil with intracellular gram, positive cocci and this horse had got strep suis epidemicus and pneumonia
•Give TMPS
- You are presented with a 10 year old horse used for general purpose riding for poor performance
- PE
–HR=44 BPM, RR=16BPM and T=38.1oC
–Cardiac auscultation revealed a III/VI holosystolic murmur PMI LICS4 and a IV/VI pansystolic murmur PMI RICS5
–NAD on respiratory auscultation and re-breathing examination
- What are the differential diagnoses for the murmurs in this case?
- Could they be responsible for the poor performance?
- How would you further investigate this case?
•What are the differential diagnoses for the murmurs in this case?
–VSD
–LHS murmur–
•Could be due to:
–overload of blood in PA, pathological pulmonary flow murmur but probably too loud for this.
–MR
–RHS murmur
- Could be due to tricuspid regurgitation
- Could they be responsible for the poor performance?
–Possible but unlikely
–VSD cause heart enlargement but usually they are dead will be okay by 10! Mostly
•How would you further investigate this case?
–Echo – heart normal size, VSD
–Could TTW or BAL
Had RAO – managed environment and was treated with oral clenbuterol
