Equine Cardiac Murmurs

Question 1

What are presentations of Cardiac disease in horses?

Answer 1

• Incidental - pre-purchase exam, ‘normal’ horse, cardiac abnormality auscultated
• Hx of poor performance
• Systemically ill horse

Question 2

What should be done with cardiac auscultation?

Answer 2

• Take time, quiet, let horse settle
• Cover whole cardiac window
• Might need to pull leg forward / get right under triceps

Question 3

What are basic heart sounds of horses?

Answer 3

• Ventricles contract = S1 = shutting of AV valves (lub)
• Ventricles relax = S2 = Shutting of semilunar valves (dup)
• S4 = Atrial contraction = (B) - just before S1
• S3 = End of rapid ventricular filling = (D) just after S2

Question 4

At normal heart rate which is slower? Systole / diastole?

Answer 4

• Systole much slower
• with higher HR systole=diastole

Question 5

What are murmurs?

Answer 5

• Turbulent blood flow

Question 6

How would you grade intensity of murmurs?

Answer 6

• Grade 1 = barely audible
• Grade 2 = Definite murmur - quieter than S1 + S2
• Grade 3 = obvious loud murmur as loud as S1+S2
• Grade 4 = v loud murmur, louder than S1+S2
• Grade 5 = v loud + has a palpable thrill
• Grade 6 = audible with stethoscope just off chest wall

Question 7

How do we describe timing of murmurs?

Answer 7

• Systolic
• Diastolic
• Continuous
  -early, mid, late,
  -pan (whole of systole - dont get S1+S2)
• holo (whole of diastole/systole - still get S1+S2)

Question 8

What else needs to be noted when describing murmurs?

Answer 8

• Grade
• Timing
• Point of maximum intensity - R/L sided
• Radiation - away from PMI
• Shape of murmur - crescendo / decrescendo
• Quality of murmur - harsh, coarse, buzzing

Question 9

What are 2 categories of murmurs?

Answer 9

• Physiological / functional = associated with normal blood flow through heart
• Pathological = associated with underlying cardiac disease

Question 10

What are 2 types of functional murmurs?

Answer 10

• Flow murmur - crescendo-decrescendo
  -always finish before S2
  -localised, early to mid systole
• Filling murmur - short duration between S2+ S3
  -early diastole
  -fit young animals - squeak / whoop / click

Question 11

What are some pathological systolic murmurs? MR/TR

Answer 11

• Mitral / tricuspid regurgitation
• holo / pansystolic
• plateau / crescendo
• Mitral more serious = more pressure (Grade 3-6 advise further investigation
• Tricuspid = grade 4-6 advise further investigation

Question 12

What are some pathological systolic murmurs? VSD?

Answer 12

• Ventricular septal defect
• loudest on right
• loud thrill
• pansystolic
• young horses

Question 13

What are some pathological systolic murmurs?

Answer 13

• Mitral / tricuspid regurgitation
• Ventral septal defects

Question 14

What are some pathological diastolic murmurs?

Answer 14

• Aortic insufficiency / Aortic regurgitation

Question 15

What is aortic insufficiency murmur?

Answer 15

– Common older horses
– Descrescendo, buzzing / cooing
– Holodiastolic
* Most common in older horses
* ‘uhhhhhhh’

Question 16

What is a PDA murmur?

Answer 16

• Normal in neonates
• Should disappear after few days
• Waxes + wanes in intensity

Question 17

What are some pathological continuous ‘machinery’ murmurs?

Answer 17

• Patent Ductus Arteriosus

Question 18

What would you do if you detected a heart murmur

Answer 18

Recommend ultrasound,
If money isn’t a problem = echo