Equine cardiac disease

Question 1

What is the S1 lub sound of heartbeat?

Answer 1

Closure of AV valves - onset of systole

Question 2

What is the S2 dub sound of heartbeat?

Answer 2

closure of Aortic/Pulmonary valves - end of systole

Question 3

What is the S3 D- sound of heartbeat?

Answer 3

Ventricular filling - early diastole

Question 4

What is the S4 Le- sound of heartbeat?

Answer 4

Atrial contraction - just before S1

Question 5

What are 2 causes of a left sided systolic murmur in a horse?

Answer 5

Mitral regurgitation (left AV valve)
Physiological ejection murmur

Question 6

What are 2 causes of a right sided systolic murmur in a horse?

Answer 6

Tricuspid (right AV valve) regurgitation

Ventricular septal defect

Question 7

What are 2 causes of a diastolic murmur in a horse?

Answer 7

Aortic regurgitation

Functional early diastolic murmur

Question 8

What does mitral regurgitation cause?

Answer 8

Left sided systolic murmur

LsCHF

Question 9

When is a holosystolic murmur heard?

Answer 9

Between the lub and the dub

Question 10

When are pansystolic murmurs heard?

Answer 10

Murmur obscures the heart sounds

Question 11

What is a physiological ejection murmur caused by?

Answer 11

Blood ejection into the great arteries

Question 12

When is a physiological ejection murmur heard?

Answer 12

Between the lub and dub but clearly ends before S2

Question 13

What does tricuspid regurgitation cause?

Answer 13

Rs systolic murmur – not of significance, found in racehorses

Question 14

What is the most common congenital heart defect in horses?

Answer 14

Ventricular septal defect

Question 15

What type of murmur does ventricular septal defect cause?

Answer 15

Loud pansystolic coarse murmur

Question 16

What is aortic regurgitation?

Answer 16

Blood leaking back from aorta into ventricles during diastole

Question 17

What type of murmur does aortic regurgitation cause?

Answer 17

Holosystolic long decrescendo murmur during diastole

Question 18

What is a functional early diastolic murmur?

Answer 18

Blood rapidly flowing into ventricle during filling and abrupt end of active relaxation

Question 19

What type of murmur does a functional early diastolic murmur cause?

Answer 19

Short murmur just before S3, after S2

Whoop sound - 2yo squeak

Question 20

What are physiological arrhythmias in a horse?

Answer 20

First/second degree AV block

Sinus arrhythmia

Question 21

What are pathological arrhythmias in a horse?

Answer 21

Atrial fibrillation

Ventricular/atrial tachycardia

Question 22

What is variations in R-R interval called?

Answer 22

Sinus arrhythmia

Question 23

What causes atrial fibrillation in horses?

Answer 23

High vagal tone and atrial dilation – reduces ventricular filling

Question 24

How can you treat atrial fibrillation?

Answer 24

Can just leave if not exercising
Oral quinidine sulphate
Transvenous electrical cardioversion if not underlying heart disease