L25: Congenital Anomalies

Question 1

What are the most common congenital cardiac anomalies in dogs?

Answer 1

PDA, pulmonic stenosis, subaortic stenosis, mitral/tricuspid valve dysplasia, persistent right aortic arch (PRAA)

Question 2

What are the most common congenital cardiac anomalies in catties?

Answer 2

Mitral/ tricuspid valve dysplasia
Atrial septal defect
Ventricular septal defect
Excessive moderator bands in L ventricle

Question 3

What are the most common congenital cardiac anomalies in piggies?

Answer 3

subaortic stenosis, endocardial cushion defects

Question 4

What are the most common congenital cardiac anomalies in cattle?

Answer 4

ASD, VSD
transposition of major vessels
Valvular haemocysts

Question 5

What are the most common congenital cardiac anomalies in horses?

Answer 5

VSD

Question 6

What are the most common locations for an ectopic heart?

Answer 6

pre-sternal sub-cut

intra-abdominal pre-sternal

Question 7

What is generally the significance of a lack of parietal pericardium?

Answer 7

generally asymptomatic

Question 8

Describe the blood supply of a foetus

Answer 8

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

Question 9

How does foetal blood flow change after birth?

Answer 9

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

Question 10

How soon after birth does the patent ductus arteriosus close in foals and calves?

Answer 10

Foal >1 week
Calves 2-3 weeks

So might be normal to heart heart murmur!

Question 11

Which species is a patent foramen ovale a common finding? is it significant ?

Answer 11

ruminants

Generally too small to be classified as a true atrial septal defect

Question 12

Describe an uncomplicated PDA

Answer 12

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

Question 13

What does an uncomplicated PDA sounds like

Answer 13

constant murmur during systole and diastole

“washing machine murmur”

Question 14

What are some adverse effects of having an uncomplicated PDA

Answer 14

dilation of arteries
eccentric hypertrophy of LA –> pulm hypertension developing
Risk of thrombosis due to turbulence

Question 15

What makes an uncomplicated PDA a complicated PDA?

Answer 15

a larger calibre ductus –> more blood shunting –> increasing pressure so that pulm artery > aorta

Question 16

Describe a complicated PDA?

Answer 16

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

Question 17

What are some clinical signs of a complicated/ large calibre PDA that has reversed?

Answer 17

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

Question 18

What is the difference between an osmium premium and osmium secondum in terms of atrial septal defects?

Answer 18

ostium primum is small and low, secondum is larger

Question 19

What generally happens to the patent foramen ovael after birth? is it considered a true ASD?

Answer 19

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

Question 20

What adverse effect can an atrial septal defect cause ?

Answer 20

shunting of blood from LA to R –> inc central venous pressure –> volume overload on RA and RV –> eccentric hypertrophy

Question 21

What are some common consequences of a ventricular septal defect ?

Answer 21

Depends on location & diameter.

Large= L to right shunting (LV v high pressure –> RV volume overload during diastole –> pressure equilibrations

Question 22

Do septal defects eventually close? how?

Answer 22

yeah, due to hypertrophy and fibrosis (healing of damage done due to turbulence)

Question 23

What are endocardial cushion defects?

Answer 23

Poor cardiac development into the 4 correct chambers :(

Question 24

what are some common defects associated with endocardial cushion defects?

Answer 24

High VSD, low ASD
Dysplasia of mitral and tricuspid valve leaflets
common atrioventricular canal

Question 25

What is a persistent trunks arteriosus?

Answer 25

incomplete separation of the trunk that should form the aorta and pulmonary artery

Question 26

What is an overriding aorta?

Answer 26

one that straddles a VSD so receives blood from both RV and LV

Question 27

What is the tetralogy of fallot? (hint: 3 primary defects, 1 2ary)

Answer 27

1. VSD 2. Pulmonic stenosis 3. Overriding aorta 4. Concentric hypertrophy of RV due to systolic pressure overload

Question 28

What are some clinical consequences of tetralogy of fallot

Answer 28

huge exercise intolerance, cyanosis, growth retardation

Question 29

What are some consequences of pulmonic stenosis?

Answer 29

Dilation of pulmonic artery | Pressure overload RV @ systole, concentric hypertrophy

Question 30

What are some consequences of subaortic stenosis?

Answer 30

Fibrosis and narrowing under aortic valve --> dilation aorta post stenosis --> pressure overload LV during systole --> concentric hypertrophy

Question 31

What are some consequences of mitral valve dysplasia?

Answer 31

mitral valve stenosis or insufficiency | Causes volume overload on LA/ LV --> dilation & eccentric hypertrophy --> +/- left sided congestive heart failure

Question 32

What are some consequences of tricuspid valve dysplasia?

Answer 32

Tricuspid valve stenosis or insufficiency | Causes volume overload on RA/ RV --> dilation & eccentric hypertrophy --> +/- R side heart failure

Question 33

What is the most common vascular ring anomaly in animals

Answer 33

Persistent right aortic arch (PRAA). | Common in dogs and cattle

Question 34

How does a persistent right aortic arch cause clinical signs in an animal?

Answer 34

oesophagus becomes trapped against trachea --> megaoesophagus cranially --> regurgitation of food --> +/- aspiration pneumonia

Question 35

What is endocardial fibroelastosis?

Answer 35

subendocardial collagen and elastic deposition --> prominent growths --> reduced compliance Burmese kittens

Question 36

In which species are congenital valvular cysts common?

Answer 36

Calves, alpaca crias, llama crias

Question 37

what is the common gross appearance of a congenital valvular cyst ?

Answer 37

generally blood filled lil cystie