Cardiac assessment in equid Flashcards
Discuss manifestations of cardiac disease?
Cardiac murmur
Differential diagnosis
- Physiological murmur
- Murmur caused by congenital abnormality
Poor performance
- Rarely due to cardiac problem:
- Consider –Lameness, Lower respiratory, upper respiratory, muscular
- Considerable cardiac ‘reserve’
- Consider –Lameness, Lower respiratory, upper respiratory, muscular
Collapse / sudden death
- Rare
- Concurrent (secondary ventricular dysrrhthmias)
- Vascular catastrophe
Congestive heart failure
- Rare in horses
What else affects membrance colour–
NITRATE, circulation. SIRS
What types of cardiac disease can you identify?
Murmur -endocardial
Arrhythmia –myocardial
Discuss what pulses can tell you?
Pulses : Arterial (transverse facial artery cheek artery) and venous
Jugular distension is an indicator of reduced cardiac return. Jugular brings blood back down from head to heart.
- Right sided Cardiac failure
- Thoracic disease
- Pericardial disease
What can peripheral oedema tell us?
Periphery : Oedema can be a sign of
- Right sided heart failure
- Hypoproteineamia
- Vascular disease
What can mucous membranes tell us?
Perfusion
hypovolaemia
Discuss jugular pulsation?
Normally visible in distal third of neck
- Dependant on head and neck position
- CVD jugular pulse goes higher up head
- Or leaning on strap see it higher
Discuss left sided heart failure?
Left sided heart failure
- Causes pulmonary Oedema can be caused by:
- Ruptured chordae tendonae
- Bacterial endocarditis
- Congenital cardiac disease
Discuss right sided heart failure?
Right sided heart failure
Peripheral oedema, pitting oedemaon ventrum of horse caused by:
- Chronic endocardial disease
What are some tips on auscultation?
Most problems
- Listening too far back
- Listening too low down
- Not listening on right hand side
Discuss the normal heart sounds?
S4 (shh) 1 st sound heard
- Onset of atrial systole -Audible in 60% of TB
S1 (Lub)
- Onset of ventricular systole
- Turbulent blood flow Closure of AV valves opening of Semilunar valves
- Loudest over LIC 5
- May be louder if Hypertension, adrenaline, MVD
S2 (Dub)
- Onset of diastole
- Closure of semilunar valves, open AV ventricular filling
- Loudest over LIC 4
- May be louder if fever, adrenaline, anaemia
S3 (de)
- Just after opening of AV valves Rapid ventricular filling
- Loudest over cardiac apex (low LIC5)
What causes murmurs in the normal horse?
Heart sounds caused by turbulence
- Closure of cardiac valves
- High velocity flow
Murmurs
- Forward or reverse flow
A 6 Year old TB Gelding -presents with Hx of poor performance the cardiac rhythm is regularly irregular.
What are differential diagnoses?
Atrial fibrillation, secondary AV block (main suspicion)
What is the significance of 2ndary AV block?
Common in horses not clinically significant with regards poor performance
8 Year old WB gelding. Poor performance and epistaxis . 3 months duration. Thought to be ‘the virus’ but others are now normal the rhythm is Irregularly irregular. Couldn’t hear S4. what would you think it would be?
Atrial fibrillation confirmed with ECG
How should you assess cardiac murmurs?
Cardiac auscultation
- Timing and PMI
- Determine valve affected
- Determine a TENTATIVE DIAGNOSIS
History and physical examination
- Determine which horses require further investigation
- Does horse have any signs of cardiac compromise we can identify
2 main forms of investigation:
Echocardiography: Confirm diagnosis, prognosis & safety (to ride)
Electrocardiography: Concurrent dysrrhythmias–safety (to ride)
How are murmurs classified?
Grade / Intensity
- Poor indicator of severity
- But saying that quite murmurs are less likely to be important
When does it occur/Timing
- Systole vs Diastole
Where do they Radiate
- Dorsal or Ventral
Where is point of maximal intensity
- Cranial -intercostal space 4
- Caudal -intercostal space 5
Discuss murmur grades and what they mean?
- Quiet murmur often difficult to identify
- Murmur quieter than heart sounds
- Murmur as loud as S1 and S2
- Murmur louder than S1 and S2
- Loud cardiac murmur with a precordial thrill (what fly has on right hand side, buzz and vibration can feel against your hand on chest)
- Murmur audible with stethoscope off thoracic wall
Discuss jugular venous pulses?
3 phases to jugular pulses normally:
- Atrial contraction
- Carotid contraction
- Ventricles contract
Discuss timings and how to define murmurs with respect to timings?
What are other assessment of cardiac function?
ECG
Blood pressure
- Direct or indirect methods
Cardiac output
- Dilution techniques (dye, temperature)
- Ultrasound
- VO2 Max.
- Maximum tissue uptake
- Requires high speed treadmill, expired gas analysus
What causes heart murmurs in horses?
Normal blood flow
- Physiological (ejection type) murmurs
- Tend to be systolic in aortic valve
- Fit horse excited cause high velocity of flow
- Tend to be higher pitched
Valvular regurgitation
Caused by valvular disease:
- Endocardiosis(congenital)
- Endocarditis (bacterial)
Cardiac defects
Ventricular septal defects (fly has this)
Discuss types of endocardial disease?
Endocardiosis
- Valvular degeneration –progressive
- Can effect Mitral, aortic, tricuspid valves
Endocardititis
- Bacterial in origin secondary to bacteraemia
- Often seen in Cattle: Liver abscess, TRP traumatic reticular peritonitis, mastitis
- Equine: Dental, respiratory, thrombophlebitis (leeding to seeding)
Other causes
- Valve dysplasia
- Valvulitis
- Valve prolapse
- Ruptured chordae tendinae
Discuss clinical signs of bacterial endocarditis?
Clinical signs:
- Congestive heart failure
- Fever, cardiac murmur, tachycardia, tachypnoea
- Associated with acute onset murmu
Look at this table of bacterial endocarditis causes in bovine, equine and porcine?
Dicuss use of echocardiography?
Uses of echocardiography
2D / M-mode
- Assess valve structure / disease
- Assess chamber enlargement
- Acute disease so no chamber enlargement
Doppler
- Assess degree of valvularregurgitation
Discuss treatment and prognosis of bacterial endocarditis?
Treatment
- Broad spectrum antibiotics based on sensitivity
Prognosis
Guarded even after bacteriological cure
- Permanent structural damage to valve
- Right-sided lesions may have return of performance
Septic emboli may shed to distant sites
- Lungs (right heart)
- Kidneys / Joints etc (left heart)
Summarise cardiac assessment?
A thorough cardiac examination is essential to document causes of cardiac murmurs
- Not all cardiac murmurs are indicative of cardiac pathology
- Congestive heart failure is uncommon in horses
