Equine Cardiology

Question 1

what types of murmurs are common in horses?

Answer 1

soft systolic

Question 2

how many heart sounds are normal to hear in a horse?

Answer 2

two
three
four
split S2

Question 3

how are cardiac murmurs described?

Answer 3

timing
intensity- grade
point of maximum intensity
quality/pitch

Question 4

what are the causes of diastolic murmurs?

Answer 4

aortic insufficiency- common
pulmonic insufficiency

Question 5

what can cause a regurgitant quality systolic murmur?

Answer 5

mitral regurgitation
tricuspid regurgitation

Question 6

what are the options for quality/pitch of a murmur?

Answer 6

musical
harsh/soft
squeak
shape- crescendo/decrescendo, band/plateau

Question 7

what diagnostic procedures can be done for a cardiac murmur?

Answer 7

ECG
echocardiography
biomarkers

Question 8

what is electrocardiography useful for in horses?

Answer 8

rate and rhythm only
base apex lead

Question 9

what is holter ECG useful for?

Answer 9

intermittent arrhythmia
monitoring of clinically relevant arrhythmia during treatment
monitoring at-risk patients

Question 10

what heart rate is expected in a horse at a walk?

Answer 10

50-80 bpm

Question 11

what heart rate is expected in a horse at a trot?

Answer 11

80-120 bpm

Question 12

what is the best non-invasive technique of looking at the heart in real time?

Answer 12

echocardiography

Question 13

what are some indications for an echo?

Answer 13

pre-purchase exam
evaluation of murmurs or arrhythmia
unexplained poor performance

Question 14

what does elevated cardiac troponin-I indicate?

Answer 14

myocardial injury
ruptured aortic jet lesion
sepsis
endurance racing

Question 15

is there an association between presence of a murmur and racing performance?

Answer 15

no

Question 16

what with a “functional” murmur would indicate an echo should be performed?

Answer 16

getting louder over time

Question 17

what left-sided systolic or aortic murmurs should you recommend an echo for?

Answer 17

grade III-VI/VI

Question 18

what is normal heart rate in a horse?

Answer 18

23-44

Question 19

what are the causes of ejection quality systolic murmurs?

Answer 19

innocent/functional- common
fever
anemia
ventricular septal defect
aortic stenosis- rare
pulmonic stenosis- rare

Question 20

what is the heart rate for cantering and galloping?

Answer 20

canter: 120-150
gallop: 150-200

Question 21

what should you look at with echocardiography?

Answer 21

measure chamber size and wall thickness
valve motion
direction, velocity, turbulence of blood flow
systolic and diastolic function

Question 22

when might you see a globoid heart with radiographs?

Answer 22

pericarditis/pericardial effusion

Question 23

when should an echo be performed?

Answer 23

previously diagnosed functional murmur louder over time
grade >III/VI left sided systolic or aortic murmur
grade >IV/VI right sided systolic murmur
suspected congenital heart lesion
continuous or combined systolic-diastolic murmur
clinically important arrhythmia
suspected myocardial injury
suspicion of congestive heart failure

Question 24

what does atrial fibrillation require?

Answer 24

a trigger to start and substrate to maintain it

Question 25

what is paroxysmal atrial fibrillation?

Answer 25

resolves spontaneously- usually race horses, resolved by 24 hours

Question 26

when does the loss of atrial contribution in atrial fibrillation become more important?

Answer 26

during exercise or with underlying heart disease: heart rate increased

Question 27

does atrial fibrillation shorten the lifespan of most horses with it?

Answer 27

no

Question 28

when are horses not suitable to be ridden?

Answer 28

cannot achieve performance
maximal heart rate exceeds 220
ventricular ectopy seen with exercise

Question 29

when should you treat atrial fibrillation?

Answer 29

persists >48 hours
normal heart rate
no other heart disease or electrolyte abnormalities

Question 30

when should you not treat atrial fibrillation?

Answer 30

secondary to underlying heart disease
left atrial diameter enlarged
resting tachycardia

Question 31

how can you convert atrial fibrillation?

Answer 31

quinidine sulfate
transvenous electrical cardioversion

Question 32

does quinidine sulfate or transvenous electrical cardioversion have a better conversion rate for atrial fibrillation?

Answer 32

transvenous electrical cardioversion is better with longer-standing atrial fibrillation

Question 33

what is the success rate of converting atrial fibrillation?

Answer 33

65-90%
better if less than a month, less likely if more than 3 months

Question 34

what can cause acute onset loud murmur?

Answer 34

bacterial endocarditis
ruptured chordae tendinae
ruptured sinus of valsalva
previous murmur that was quiet and missed becomes louder

Question 35

what does aortic regurgitation present as?

Answer 35

diastolic “musical” murmur
water hammer pulse
very common older horses

Question 36

what is a good indicator of severity of aortic regurgitation?

Answer 36

arterial pulse quality: bounding
intensity of murmur is not

Question 37

what is the prognosis of aortic regurgitation?

Answer 37

older horse with mild: excellent
young horse with severe: poor

Question 38

what is the prognosis of ruptured chordae tendinae or sinus of valsalva?

Answer 38

grave

Question 39

how can you treat ventricular tachycardia?

Answer 39

lidocaine
magnesium sulfate
treat underlying disease

Question 40

what are the most common sites of endocarditis in horses?

Answer 40

aortic and mitral valves

Question 41

what is the prognosis of endocarditis?

Answer 41

poor to guarded for both survival and performance

Question 42

what is the most common congenital heart lesion in horses?

Answer 42

ventricular septal defect