Examination of the cardiovacular system in horses

Question 1

Methods of cardiovascular examination

Answer 1

Physical examination
Ancillary diagnostics
topography of the cardiac region

Question 2

physical examination methods

Answer 2

inspection (heart, vessels)
palpation (heart, vessels)
ausculation (heart)
percussion (heart)

Question 3

ancillary diagnostic aids

Answer 3

Electrocardiography (ECG)
Echocardiography
Phonocardiography (PCG)
Blood pressure measurement
Pericardiocentesis
Cardiac catheterization
Laboratory tests (AST, CK, LDH, cardiac troponin I)

Question 4

Location of the heart

Answer 4

heart base: 2nd to 6th intercostal space (ICS)
twisted anticlockwise
Right side: almost cranially
Left side: on the left and caudally

Question 5

location of the heartbeat

Answer 5

Left side: 3rd - 5th ICS

Right side 3rd to 4th ICS

Question 6

inspection and palpation of the cardiac region

Answer 6

Inspection: trauma, deformity

Palpation

• local and intensity of heart beat
• heart rate
• trauma, deformity
• pain
• precordial thrill, fremitus

Question 7

heart sounds in the horse

Answer 7

S1: begining of systole

S2: end of systole

S3

S4

Question 8

Heart murmurs in horses

Answer 8

Prolonged audible vibrations

Developing in a usually silent period of the cardiac cycle

Normal (functional)

• usually caused by vibrations that attend the ejection of blood from the heart during systole
• or the rapid filling of the ventricles during early diastole

Sbnormal (pathological)

Question 9

physiological (flow) murmurs - systolic murmur

Answer 9

• Caused by blood flow in aorta and pulmonary artery in early systole.
• Left side of thorax
• PMI over aortic or pulmonary valves
• Grade 1-3/6
• Early midsystolic
• Crescendo-decrescendo or decrescendo
• Localized and brief
• Intensity may change with exercise

Question 10

physiological (flow) murmurs - diastolic murmur

Answer 10

Caused by ventricular filling

Common in young horses and thoroughbreeds

Left side of thorax

Grade 1-3/6

Early diastolic (S2-S3) or late diastolic (S4-S1)

Quality is often musical/squeaking

Question 11

Classifications of endocardial murmurs

Answer 11

timing - systolic, diastolic - early, mid, late

Duration

Grade

Point of maximum intensity

Quality (shape)

• band/plateau
• crescendo-decrescendo
• decescendo
• crescendo

frequency

radiation

Question 12

Percussion of the cardiac area

Answer 12

pleximeter + percussion hammer
Detection of pain in the cardiac area
Area of cardiac dullness

Question 13

Electrocardiography

- resting ECG

Answer 13

base-apex lead: most commonly used

Einthoven lead can also be used

Question 14

Electrocardiography

- Holter and telemetric ECG

Answer 14

at rest
Exercising ECG
special leads
- during natural work
- on treadmill

Question 15

Blood tests

Answer 15

AST, CK and LDH levels and isoenzymes

CK: cardiac muscle contains mainly MB dimer in humans, bu MM in horses

LDH: 5 isoenzymes, cardiac muscle contains mainly LDH1 (and LDH2)

tests for cardiac troponin I and T are available in horses

Question 16

Describe the heart sound: S1

Answer 16

S1: begining of systole
- caused by the initial movement of the ventrile, the abrupt arrest of blood flow as AV valves tenses, and the early part of ejection

Question 17

Describe the heart sound: S2

Answer 17

S2: end of systole

- caused by the change in direction of blood flow, closing the semilunar valves

Question 18

Describe the heart sound: S3

Answer 18

S3

• termination of rapid ventricular fillin
• commonly heard at caudal and dorsal to the apex beat

Question 19

Describe the heart sound: S4

Answer 19

S4

- atrial contraction and sudden arrest of the distended ventricle