Murmurs in Young Animals Flashcards
(42 cards)
What causes innocent murmurs?
> v TP and v PCV - low viscosity blood
^ CO as animal growing
-> turbulent flow of blood in the absence of pathology
Characteristics of a flow or innocent murmur?
- no clinical signs
- low intensity <3/6
- reduces in intensity and disdappears with age (by 6 months)
Which species has highest incidence of congenital heart defects?
dogs 1/100 live births
What are the 4 main types of abnormality?
> valvular malformations or dysplasia - stenosis or insiffuiciency of any valves > persistence of foetal vessels - PDA > malformation of vasculature - vascular ring anomaly > Septal defects * complex defects eg. tetralogy of fallot involve multiple defects (pulmonic stenosis and septal defect)
What clinical signs may congential heart problems present as unrelated to CV system?
- hepatic encephalopathy with PSS
- regurgitation with VRA
What are potential causes of systolic murmurs?
> left - apex: mitral insufficiency - base: AS/PS > right - sternal border: VSD - cranial: triceps insusfficiency or aortic stenosis
Other than murmur, what clinical signs may indicate congential heart defects?
> cyanosis
- cyanotic heart disease where R-L shunt can occour (BAD)
Pulse quality
- exaggerated (may be PDA, waterhammer pulse)
- poor (may be aortic stenosis > damping effect)
What type of shunt creates volume overload?
Left -> Right
What type of shunt causes pressure overload?
Stenotic outflow tracts
See lecture for diagrams of the path of the shunting erythrocyte!
Which species are VSDs the most common defect in?
All except dog!
Dog - PDA `
What type of shunt does VSD cause? So where is murmur heard? Implications of this?
Left - right
- murmur heard loudest on RIGHT with palpable thrill on the R thoracic wall
- colume overloaded left side and pulmonary circulation
Tx and prognosis of VSD?
- no definitive Tx
- prognosis fair if defect is small and pressure difference maintained across defect
Where specifically is VSD likely to occour?
Near great vessels (near top)
How does relative pulmonic stenosis occour?
L-V shunt overloads pulmonary circulation as aortic CO is always maintained by homeostatic mechanisms
-> pulmonary artery is relatively too thin for volume of blood passing thorugh
What is the peak left and right ventricular pressure in systole?
LV: 120mmHg
RV: 35mmHG
What does speed of flow thorugh a defect indicate?
Faster the flow, smaller the defect, better the prognosis!
What is a small VSD termed?
Restrictive defect
What causes cyanotic congenital heart disease? PE findings?
- RV pressure overload and systemic hypoxia
- PE: poorly grown, may be no murmur or quiet murmur
Diagnositcs for cyanotic congential heart disease?
- RVH
- shunting defect
- polycythaemia may be present (abnormally ^ Hbg conc due to ^RBC or v volume)
Tx pulmonic hypertension or pulmonic stenosis (cyanotic congenital heart disease)?
no definitive tx
- palliative tx for certain defects
- control PCV
What is a potential RV systolic pressure with pulmonary hypertension?
140mmHg
Why may murmurs be less audible with more severe defects?
if RV pressure ^, pressure gradiant is less so velocity v and murmur less audible
What causes ^ RV pressure?
Pulmonic hypertension
