Equine Murmurs

Equine Murmurs

1. Non-pathogenic murmurs

   • Ejection type
     • Systolic
       • variable intensity at different HRs
       • < 3/6, early to mid systolic, crescendo
     • Young, fit, neonates. <3.6, variable intensity at different HRs
     • Diastolic
       • <3yo, low grade presystolic of early diastolic
     • no bearing on future use
   • Metabolic
     • Decreased blood viscosity
       • anaemia, Babesia, severe thrombocytopaenia
         • = increased turbidity
     • Altered haemodynamics
     • Altered peripheral resistance
       • colic, endotoxaemia

2. Pathological

   • Systolic
     • Tricuspid valve regurgitation
       • PMI: right base
       • rarely affect performance
         • investigate for RA dilation if G >3/6
       • Large defect
         • + Jugular pulse, signs of RsCHF
       • 43%, stenosis 0.3%
     • Mitral insufficiency
       • PMI: left base, ICS 5
       • G <3 or widespread radiation: Advise against athletic use
       • Structural changes
         • Fractional shortening <30% & ex intol = Gaurded px
         • leaflet thickening, CT rupture, hyperdynamic LV, enlarged pul. a. % LA enlargement = poorer px
       • 19%, stenosis 1%
     • Acute onset following chordae tendonae rupture
   • Diastolic
     • Aortic insufficiency
       • may affect performance
         • Performance horses: Echo, if significantly enlarged LV internal dilation then reccomend retirement
         • often progressive, monitor if >2
       • volume overload of LV = LV hypertrophy, overload and pulmonary hypertension
         • Eventual atrial dilation = AF
     • Pulmonic insufficiency
       • rarely heard on auscutation, unlikely to compromise heart on its own
   • Congenital
     • ventricular septal defect
       • commonest congenital defect
       • PMI R side, G 4-5, S1 and S2 obliterated with wide radiation and thrill
       • defect <5mm may have normal life
       • life threatening forms PreX <5yo with CHF
         • Don't breed or use for athletic events
     • Tetrology of Fallot
       • pulmonic stenosis and VSD
       • Severity depends of severity of stenosis
       • R sided G 3/6 may be heard in young horses