L25: Congenital Anomalies Flashcards
What are the most common congenital cardiac anomalies in dogs?
PDA, pulmonic stenosis, subaortic stenosis, mitral/tricuspid valve dysplasia, persistent right aortic arch (PRAA)
What are the most common congenital cardiac anomalies in catties?
Mitral/ tricuspid valve dysplasia
Atrial septal defect
Ventricular septal defect
Excessive moderator bands in L ventricle
What are the most common congenital cardiac anomalies in piggies?
subaortic stenosis, endocardial cushion defects
What are the most common congenital cardiac anomalies in cattle?
ASD, VSD
transposition of major vessels
Valvular haemocysts
What are the most common congenital cardiac anomalies in horses?
VSD
What are the most common locations for an ectopic heart?
pre-sternal sub-cut
intra-abdominal pre-sternal
What is generally the significance of a lack of parietal pericardium?
generally asymptomatic
Describe the blood supply of a foetus
O2 blood from maternal placenta > L umbilical vein > through ductus venosus of liver > caudal VC, R atrium > foramen ovale > L atrium > LV > aortic arch > systemic circulation, but preferentially to myocardium & brain
How does foetal blood flow change after birth?
lungs inflate > O2 induced vasodilation pulmonary arteries > abrupt drop in pulmonary arterial pressure so DUCTUS ARTERIOSUS is bypassed and blood from RV flows to lungs
Inc pressure + volume in LA, LV, aorta due to return of blood from lungs bypasses FORAMEN OVALE
Functional closure of DUCTUS VENOSUS
How soon after birth does the patent ductus arteriosus close in foals and calves?
Foal >1 week
Calves 2-3 weeks
So might be normal to heart heart murmur!
Which species is a patent foramen ovale a common finding? is it significant ?
ruminants
Generally too small to be classified as a true atrial septal defect
Describe an uncomplicated PDA
L to R shunt develops as blood from the aorta goes into pulmonary artery
EXTRA blood back to LA = dilation, causes volume overload on LV –> ECCENTRIC HYPERTROPHY
What does an uncomplicated PDA sounds like
constant murmur during systole and diastole
“washing machine murmur”
What are some adverse effects of having an uncomplicated PDA
dilation of arteries
eccentric hypertrophy of LA –> pulm hypertension developing
Risk of thrombosis due to turbulence
What makes an uncomplicated PDA a complicated PDA?
a larger calibre ductus –> more blood shunting –> increasing pressure so that pulm artery > aorta
Describe a complicated PDA?
pulm pressure > aortic pressure
REVERSAL OF SHUNT: now goes right to left
–> venous blood bypass the lung –> goes into aorta –> generalised cyanosis to hindquarters. forelimbs maintained by subclav artery
What are some clinical signs of a complicated/ large calibre PDA that has reversed?
Shunting during systole
Deoxygenated blood circulates to cause cyanosis of caudal end, because the brachio trunk and R subclav come off proximal to the foramen so still receive O2 blood
What is the difference between an osmium premium and osmium secondum in terms of atrial septal defects?
ostium primum is small and low, secondum is larger
What generally happens to the patent foramen ovael after birth? is it considered a true ASD?
functionally closes at first breath due to a drop in pressure at the RA & an increase in pressure at the LA. flap gets pushed over to cover other flap
not true ASD
What adverse effect can an atrial septal defect cause ?
shunting of blood from LA to R –> inc central venous pressure –> volume overload on RA and RV –> eccentric hypertrophy
What are some common consequences of a ventricular septal defect ?
Depends on location & diameter.
Large= L to right shunting (LV v high pressure –> RV volume overload during diastole –> pressure equilibrations
Do septal defects eventually close? how?
yeah, due to hypertrophy and fibrosis (healing of damage done due to turbulence)
What are endocardial cushion defects?
Poor cardiac development into the 4 correct chambers :(
what are some common defects associated with endocardial cushion defects?
High VSD, low ASD
Dysplasia of mitral and tricuspid valve leaflets
common atrioventricular canal
What is a persistent trunks arteriosus?
incomplete separation of the trunk that should form the aorta and pulmonary artery
What is an overriding aorta?
one that straddles a VSD so receives blood from both RV and LV
What is the tetralogy of fallot? (hint: 3 primary defects, 1 2ary)
- VSD
- Pulmonic stenosis
- Overriding aorta
- Concentric hypertrophy of RV due to systolic pressure overload
What are some clinical consequences of tetralogy of fallot
huge exercise intolerance, cyanosis, growth retardation
What are some consequences of pulmonic stenosis?
Dilation of pulmonic artery
Pressure overload RV @ systole, concentric hypertrophy
What are some consequences of subaortic stenosis?
Fibrosis and narrowing under aortic valve –> dilation aorta post stenosis –> pressure overload LV during systole –> concentric hypertrophy
What are some consequences of mitral valve dysplasia?
mitral valve stenosis or insufficiency
Causes volume overload on LA/ LV –> dilation & eccentric hypertrophy –> +/- left sided congestive heart failure
What are some consequences of tricuspid valve dysplasia?
Tricuspid valve stenosis or insufficiency
Causes volume overload on RA/ RV –> dilation & eccentric hypertrophy –> +/- R side heart failure
What is the most common vascular ring anomaly in animals
Persistent right aortic arch (PRAA).
Common in dogs and cattle
How does a persistent right aortic arch cause clinical signs in an animal?
oesophagus becomes trapped against trachea –> megaoesophagus cranially –> regurgitation of food –> +/- aspiration pneumonia
What is endocardial fibroelastosis?
subendocardial collagen and elastic deposition –> prominent growths –> reduced compliance
Burmese kittens
In which species are congenital valvular cysts common?
Calves, alpaca crias, llama crias
what is the common gross appearance of a congenital valvular cyst ?
generally blood filled lil cystie
