Equine cardiac disease Flashcards
What is the S1 lub sound of heartbeat?
Closure of AV valves - onset of systole
What is the S2 dub sound of heartbeat?
closure of Aortic/Pulmonary valves - end of systole
What is the S3 D- sound of heartbeat?
Ventricular filling - early diastole
What is the S4 Le- sound of heartbeat?
Atrial contraction - just before S1
What are 2 causes of a left sided systolic murmur in a horse?
Mitral regurgitation (left AV valve) Physiological ejection murmur
What are 2 causes of a right sided systolic murmur in a horse?
Tricuspid (right AV valve) regurgitation
Ventricular septal defect
What are 2 causes of a diastolic murmur in a horse?
Aortic regurgitation
Functional early diastolic murmur
What does mitral regurgitation cause?
Left sided systolic murmur
LsCHF
When is a holosystolic murmur heard?
Between the lub and the dub
When are pansystolic murmurs heard?
Murmur obscures the heart sounds
What is a physiological ejection murmur caused by?
Blood ejection into the great arteries
When is a physiological ejection murmur heard?
Between the lub and dub but clearly ends before S2
What does tricuspid regurgitation cause?
Rs systolic murmur – not of significance, found in racehorses
What is the most common congenital heart defect in horses?
Ventricular septal defect
What type of murmur does ventricular septal defect cause?
Loud pansystolic coarse murmur
What is aortic regurgitation?
Blood leaking back from aorta into ventricles during diastole
What type of murmur does aortic regurgitation cause?
Holosystolic long decrescendo murmur during diastole
What is a functional early diastolic murmur?
Blood rapidly flowing into ventricle during filling and abrupt end of active relaxation
What type of murmur does a functional early diastolic murmur cause?
Short murmur just before S3, after S2
Whoop sound - 2yo squeak
What are physiological arrhythmias in a horse?
First/second degree AV block
Sinus arrhythmia
What are pathological arrhythmias in a horse?
Atrial fibrillation
Ventricular/atrial tachycardia
What is variations in R-R interval called?
Sinus arrhythmia
What causes atrial fibrillation in horses?
High vagal tone and atrial dilation – reduces ventricular filling
How can you treat atrial fibrillation?
Can just leave if not exercising
Oral quinidine sulphate
Transvenous electrical cardioversion if not underlying heart disease
