Lecture 25

Question 1

how prevalent are congenital anomalies of CVS

Answer 1

low. dogs-1% camelids/pigs-4%

Question 2

Most common congenital anomaly in dogs, cats, pigs, horse, cow

Answer 2

dog-PDA, pulmonic or subaortic stenosis
cat- tricuspid or mitral valve dysplasia
pig- subaortic stenosis,endocardial cushion defect
horse- VSD
cow- ASD,VSD, valvular hematocysts

Question 3

Why more prevalence in purebred dogs?

Answer 3

requires inheritance of several genes at different loci (polygenic inheritance)

Question 4

Most common location for an ectopic heart

Answer 4

cattle- pre sternal subcutaneous

Question 5

clinical significance of congenital absence of parietal pericardium

Answer 5

usually asymptomatic

Question 6

congenital peritoneopericardial diaphragmatic hernia

Answer 6

triangular defect in ventral diaphragm and in parietal pericardium->abdominal viscera into pericardial sac (often clinically silent)

Question 7

significant changes to fetal blood flow at birth

Answer 7

vasoconstriction of umbilical veins->dec venous return to RA and dec RA vol and pressure

• post natal lung inflationand O2 induced vasodilation of pulmonary arteries->dec pulmonary pressure->inc vol and pressure in LA and LV and aorta
• Closure of Ductus venosus, ductus arteriosus, and foramen ovale

Question 8

Which species is PDA most often detected

Answer 8

dogs (especially females)

Question 9

consequences of PDA (uncomplicated and complicated)

Answer 9

uncomplicated- L to R shunt during systole and diastole->inc volume in pulmonary artery and inc vol load on LA (dilation) and LV(dilation->chronic eccentric hypertrophy)

Complicated- pulmonary pressure inc and exceeds aortic-> shunt reversal (now R to L)->venous blood bypasses lungs-> hindquarter peripheral cyanosis (cranial blood supply before shunt)

Question 10

Patent foramen ovale common in what species> Significant? Why?

Answer 10

common in ruminants

not a true atrial septal defect, does not permit shunting (functionally closed)

Question 11

potential post natal consequences of atrial septal defect (ASD)

Answer 11

shunting-> L to R-> inc central venous pressure and volume overload on RA (dilation) and RV (dilation then chronic eccentric hypertrophy) also vol overload on LA due to return of extra blood from lungs

Question 12

Potential post natal consequences of VSD

Answer 12

depend on diameter and degree of pulmonary vascular resistance
small may be clinically insignificant
large-> L to R shunting of blood->vol overload on RV during diastole and equilibration of pressures between RV and LV->pressure overload on RV during systole

Question 13

Why do some VSD’s eventually close

Answer 13

reparative fibrosis induced by blood turbulence

Question 14

which animals are likely to develop shunt reversal and at what age?(3 at the same age)

Answer 14

PDA, ASD, or VSD within first 6 months of post natal life

large defects that allow L to R shunting of large vol of blood

Question 15

Possible defects associated with abnormal development of endocardial cushions (4 and common in)

Answer 15

high VSD or low ASD
tricuspid or mitral valve dysplasia
common AV canal
common in pigs and cats

Question 16

Myxomas

Answer 16

persistent unmodeled mesenchymal tissue of the endocardial cushions

Question 17

persistent truncus arteriosus

Answer 17

incomplete separation of the truncus arteriosus into pulmonary artery and aorta by the spiral septum->generalized cyanosis

Question 18

overriding aorta

Answer 18

the aorta straddles a high VSD and the pulmonary artery emerges from RV like normal

Question 19

4 components of tetralogy of Fallot

Clinical signs

Answer 19

3 primary
-VSD
-pulmonic stenosis
-overriding aorta
secondary compensatory 
-concentric hypertrophy of RV due to systolic pressure overload

rapid fatigue, retarded growth, cyanosis

Question 20

Consequences of pulmonic stenosis?(2) species?(1)

Answer 20

narrowing of RV outflow tract->systolic pressure overload on RV->concentric hypertrophy
post stenotic dilation of pulmonary artery
common in dogs

Question 21

consequences of subaortic stenosis (3)

Answer 21

systolic pressure overload on LV->chronic concentric hypertrophy
post stenotic dilation of aorta
arrhythmias and sudden death

Question 22

Which species have subaortic stenosis(2)

Answer 22

common in pigs and also dogs

Question 23

why does functional impact of subaortic stenosis inc over time

Answer 23

progressive turbulence induced subendocardial fibrosis and compensatory hypertrophy

Question 24

typical consequences of mitral or tricuspid valve dysplasia and what species

Answer 24

valve stenosis or more commonly valve insufficiency

catsssss

Question 25

endocardiosis is

Answer 25

an age related valvular degeneration condition

Question 26

Most common vascular ring anomaly and species

one consequence

Answer 26

persistent right aortic arch
dogs
can lead to esophageal obstruction->megaesophagus

Question 27

myocardial rhabdomyoma

and what may become of it

Answer 27

not neoplastic, but anomalous malformations of myocardial fibers
may become firm due to fibrosis and dystrophic mineralization