Approach to young animal with a murmur

Question 1

What are the steps to take when detecting murmur in a young animal

Answer 1

determine if innocent or indicative of dz
if dz, refine ddx with PE
diagnostic tests
explore tx where appropriate/refer

Question 2

What are flow murmurs and what are their characteristics?

Answer 2

high CO, reduced blood viscocity
no associated CS
low intensity (under 3/6)
reduces in intensity and disappears with age

Question 3

What do significant murmurs in your animals indicate?

Answer 3

presence of congenital heart dz
0.5-1% of all dogs

Question 4

What are the types of cardiac congenital abnormalities?

Answer 4

valvular malformations (dysplasia) (can result in stenosis or insufficiency of valves)
persistence of foetal vessel: patent ductus arteriosus
malformation of vasculature: vascular ring anomaly
septal defects
complex defects

Question 5

What are reasons for murmur discovery in young animals?

Answer 5

incidental
other CS: cyanosis, syncope, stunting, etc.
overt congestive failure
Non-cardiac signs: hepatic encephalopathy with PSS, regurgitation with VRA

Question 6

How do we investigate murmurs in young animals?

Answer 6

Hx, PE
ECG
XRAY in small animals
Specialist:
- Echocardiography
- doppler echo
- cardiac cath and angio

Question 7

What does cyanosis indicate for murmur?

Answer 7

can imply cyanotic heart dz where R to L shunting can occur

Question 8

What does pulse quality indicate for murmur?

Answer 8

Exaggerated = could be PDA
Poor = could be aortic stenosis

Question 9

What effects on the heart are seen with left to right shunts?

Answer 9

creates volume load which occur along the “path of the shunting erythrocyte”

Question 10

What effects on the heart are seen with stenoses of outflow valves?

Answer 10

cause pressure overloads
increased resistance to ejection from affected ventricles

Question 11

What is the most common cardiac defect in all species but the dog?

Answer 11

ventricular septal defects

Question 12

What is the nature of a ventricular septal defect and what does it cause?

Answer 12

failure of normal formation of interventricular septum
left to right shunt (unless there is pulmonary hypertension)

Question 13

What signs can be seen on PE with a VSD?

Answer 13

intense systolic murmur usually loudest on right
volume overload left side and pulmonary circulation

Question 14

What is the tx and prognosis for VSD?

Answer 14

Definitive tx not available
prognosis fair if defect is small and pressure difference is maintained across defect

Question 15

What is the consequence of pulmonary hypertension or pulmonic stenosis?

Answer 15

“cyanotic” congenital heart dz
usually has severe compromise
right ventricular pressure overload and systemic hypoxia

Question 16

What signs can be seen on PE with pulmonary hypertension or stenosis?

Answer 16

animal is poorly grown
may be no murmur or only very quiet because flow isn’t turbulent
RVH
may see hunting defect, may be polycythaemia

Question 17

What is the tx for cyanotic heart dz (pulm. hypertension or stenosis)?

Answer 17

no definitive tx
some palliative therapy for certain defects
need to control PCV

Question 18

What is the patent ductus arteriosis?

Answer 18

persistence of foetal connection
causes left to right shunt (unless pulmonary hypertension develops)

Question 19

What signs can be seen on PE with PDA?

Answer 19

continuous left base murmur and bounding pulses
volume loaded left side and pulmonary circulation

Question 20

What can be seen with imaging when there is a PDA?

Answer 20

with doppler: can see ductal flow
with xray: see 3 knuckles of Ao, PA, LA on a DV

Question 21

What is the tx and prognosis for a patient with PDA?

Answer 21

surgical ligation or interventional closure
prognosis is good if closed

Question 22

What is an aortic stenosis and what does it cause?

Answer 22

narrowing of left ventricular outflow tract
causes pressure overload LV

Question 23

What can be seen on PE with an aortic stenosis?

Answer 23

left base systolic murmur
good pulse
concentrically hypertrophied LV, increased aortic outflow velocity with doppler

Question 24

What is the tx for aortic stenosis?

Answer 24

Management: definitive cure not available = medical management is best option even if evidence isn’t strong

Question 25

What is a pulmonic stenosis and what does it cause?

Answer 25

narrow of RVOT
causes right ventricular pressure overload

Question 26

What can be seen on a PE with pulmonic stenosis?

Answer 26

left bases systolic murmur, apex beat may be on the right
RVH, pulmonary artery dilatation, increased pulmonary outflow velocity with doppler

Question 27

What is the tx for pulmonic stenosis?

Answer 27

management: balloom valvuloplasty and surgical patch grafting have been described

Question 28

What is a vascular ring anomaly and its consequence?

Answer 28

moalformation of great vessels
causes obstruction of thoracic oesophagus

Question 29

What can be seen on a PE with a vascular ring anomaly?

Answer 29

no murmur, signs of regurgitation
dilated oesophagus cranial to heart

Question 30

What is the tx for vascular ring anomaly?

Answer 30

management: surgical relief of compression
even then prognosis is guarded

Question 31

What are atrial septal defects and what do they cause?

Answer 31

failure of formation of atrial septum
may have a left to right shunt but often not significant

Question 32

What can be seen on PE with atrial septal defect?

Answer 32

may be normal, may have soft murmur over pulmonic valve, “relative” pulmonic stenosis
often found incidentally, often missed

Question 33

What is the tx for atrial septal defects?

Answer 33

usually not required

Question 34

What is mitral and tricuspid dysplasia and what does it cause?

Answer 34

malformation of one or both AV valve
stenosis and/or insufficiency of valve leads to volume overload of L (M) or right (T) side

Question 35

What can be found on a PE with mitral and tricuspid dysplasia?

Answer 35

murmurs of MR or TR
enlargement of left/right side

Question 36

What is the tx for mitral or tricuspid dysplasia?

Answer 36

definitive repair attempted surgically but with limited success