Approach to young animal with a murmur Flashcards
What are the steps to take when detecting murmur in a young animal
determine if innocent or indicative of dz
if dz, refine ddx with PE
diagnostic tests
explore tx where appropriate/refer
What are flow murmurs and what are their characteristics?
high CO, reduced blood viscocity
no associated CS
low intensity (under 3/6)
reduces in intensity and disappears with age
What do significant murmurs in your animals indicate?
presence of congenital heart dz
0.5-1% of all dogs
What are the types of cardiac congenital abnormalities?
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
What are reasons for murmur discovery in young animals?
incidental
other CS: cyanosis, syncope, stunting, etc.
overt congestive failure
Non-cardiac signs: hepatic encephalopathy with PSS, regurgitation with VRA
How do we investigate murmurs in young animals?
Hx, PE
ECG
XRAY in small animals
Specialist:
- Echocardiography
- doppler echo
- cardiac cath and angio
What does cyanosis indicate for murmur?
can imply cyanotic heart dz where R to L shunting can occur
What does pulse quality indicate for murmur?
Exaggerated = could be PDA
Poor = could be aortic stenosis
What effects on the heart are seen with left to right shunts?
creates volume load which occur along the “path of the shunting erythrocyte”
What effects on the heart are seen with stenoses of outflow valves?
cause pressure overloads
increased resistance to ejection from affected ventricles
What is the most common cardiac defect in all species but the dog?
ventricular septal defects
What is the nature of a ventricular septal defect and what does it cause?
failure of normal formation of interventricular septum
left to right shunt (unless there is pulmonary hypertension)
What signs can be seen on PE with a VSD?
intense systolic murmur usually loudest on right
volume overload left side and pulmonary circulation
What is the tx and prognosis for VSD?
Definitive tx not available
prognosis fair if defect is small and pressure difference is maintained across defect
What is the consequence of pulmonary hypertension or pulmonic stenosis?
“cyanotic” congenital heart dz
usually has severe compromise
right ventricular pressure overload and systemic hypoxia
What signs can be seen on PE with pulmonary hypertension or stenosis?
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
What is the tx for cyanotic heart dz (pulm. hypertension or stenosis)?
no definitive tx
some palliative therapy for certain defects
need to control PCV
What is the patent ductus arteriosis?
persistence of foetal connection
causes left to right shunt (unless pulmonary hypertension develops)
What signs can be seen on PE with PDA?
continuous left base murmur and bounding pulses
volume loaded left side and pulmonary circulation
What can be seen with imaging when there is a PDA?
with doppler: can see ductal flow
with xray: see 3 knuckles of Ao, PA, LA on a DV
What is the tx and prognosis for a patient with PDA?
surgical ligation or interventional closure
prognosis is good if closed
What is an aortic stenosis and what does it cause?
narrowing of left ventricular outflow tract
causes pressure overload LV
What can be seen on PE with an aortic stenosis?
left base systolic murmur
good pulse
concentrically hypertrophied LV, increased aortic outflow velocity with doppler
What is the tx for aortic stenosis?
Management: definitive cure not available = medical management is best option even if evidence isn’t strong
What is a pulmonic stenosis and what does it cause?
narrow of RVOT
causes right ventricular pressure overload
What can be seen on a PE with pulmonic stenosis?
left bases systolic murmur, apex beat may be on the right
RVH, pulmonary artery dilatation, increased pulmonary outflow velocity with doppler
What is the tx for pulmonic stenosis?
management: balloom valvuloplasty and surgical patch grafting have been described
What is a vascular ring anomaly and its consequence?
moalformation of great vessels
causes obstruction of thoracic oesophagus
What can be seen on a PE with a vascular ring anomaly?
no murmur, signs of regurgitation
dilated oesophagus cranial to heart
What is the tx for vascular ring anomaly?
management: surgical relief of compression
even then prognosis is guarded
What are atrial septal defects and what do they cause?
failure of formation of atrial septum
may have a left to right shunt but often not significant
What can be seen on PE with atrial septal defect?
may be normal, may have soft murmur over pulmonic valve, “relative” pulmonic stenosis
often found incidentally, often missed
What is the tx for atrial septal defects?
usually not required
What is mitral and tricuspid dysplasia and what does it cause?
malformation of one or both AV valve
stenosis and/or insufficiency of valve leads to volume overload of L (M) or right (T) side
What can be found on a PE with mitral and tricuspid dysplasia?
murmurs of MR or TR
enlargement of left/right side
What is the tx for mitral or tricuspid dysplasia?
definitive repair attempted surgically but with limited success
