Congenital cardiovascular pathology Flashcards
Congenital atrial defects
Persistent foramen ovale
Septal defects
Congenital ventricular defects
Septal defects
Congenital vascular defects
Patent ductus arteriosus (PDA)
Pulmonic stenosis
Aortic stenosis
Persistent IV right aortic arch
Dextraposition of aorta
Transposition of great vessels
Congenital complex defects
Tetralogy of fallot
Miscellaneous congenital defects
Haematocysts
Valvular dysplasia
Endocardial fibroelestosis
Ectopia
Patent ductus arteriosus breed predispositions
Chihuahua, bichon frise, English springer spaniel, Pomeranian, poodle, keeshond, and Shetland sheepdog
In poodles it is inherited
PDA
Shunts blood from pulmonary artery to aorta
Gives rise to pulmonary hypertension
At first blood is shunted from the left to the right ventricle and this may lead to reversal of flow through the PDA and clinical development of cyanosis.
Right and left ventricular hypertrophy and cardiac failure are secondary effects.
Persistent foramen ovale and atrial septal defect
(Cattle)
The most frequent is failure of closure of the foramen ovale
True septal defects of the interatrial septum arise either due to failure of growth of septum secundum or failure of separation of right pulmonary veins and anterior vena cava.
Pulmonary hypertension may develop leading eventually to reversal of flow through the atrial communication.
Breed disposition of persistent foramen ovale
Greatest frequency of persistent foramen ovale is in boxer, Doberman pinscher, and Samoyed.
Ventricular septal defects
Cat and cattle.
A common defect in animals.
It is a failure of complete development of the interventricular septum (membranous or muscular).
It occurs more commonly in the upper portion of the interventricular septum (membranous).
Postnatally the effect of these defects depends on the size of the opening.
There is often a left to right shunt.
Left ventricular output is maintained by an increased end diastolic volume and increased contractility.
The right ventricle is confronted by a large systolic and diastolic load.
Both ventricles undergo hypertrophy.
Breed disposition for VSD
In dogs it is most likely in English Bulldogs, English Springer Spaniels, and West Highland White Terriers
Tetralogy of fallot
Dog.
It is a complicated cardiac anomaly with four (tetrad) anomalies:
§ ventricular septal defect,
§ pulmonic stenosis,
§ dextraposition of the aorta.
The fourth lesion, hypertrophy of the right ventricle is secondary or compensatory.
Invariably results in clinical signs of fatigue, cyanosis and polycythemia due to hypoxia.
Growth is usually retarded.
Breed predisposition for tetralogy of fallot
Inherited in Keeshond dogs and is frequent in English bulldogs
Anomalies from failure of normal valvular development
Pulmonic stenosis
Subaortic stenosis
Dysplasia of tricuspid and mitral valves
Breed predisposition for pulmonic stenosis
It is inherited in beagles, English bulldog, Chihuahua and probably in other breeds.
Pulmonic stenosis
The defect can be due to deformity of the valves themselves (valvular stenosis) or as a formation of a circumferential band of fibrous or muscular tissue beneath the valve (subvalvular stenosis).
There is post stenotic dilatation of the pulmonary trunk.
Concentric right ventricular hypertrophy is present because of the increased systolic pressure generated within the ventricle.
Breed predisposition of subaortic stenosis
Dog and pig.
It appears to be inherited in German shepherd, boxer and Newfoundland dogs.
Subaortic stenosis
thickness and endocardial valvular fibrosis that encircles the left ventricular outflow below the aortic valve.
Secondary lesions develop such as ventricular concentric hypertrophy, foci of myocardial necrosis and post stenotic dilation.
Dysplasia of tricuspid and mitral valves
Cat (tricuspid valve).
Valve leaflets are distorted and chordae tendinae shortened and thickened.
Valve leaflets are distorted with enlarged annulus, short thick chordae tendinae and malpositioned papillary muscles.
Right atrium is enlarged due to valvular insufficiency leading to regurgitation of blood through the incompetent valve.
The right ventricle becomes hypertrophied.
Anomalies from malpositioning of the great vessels
Persistent right aortic arch
Persistent right aortic arch
Dog.
Arises when the right IV aortic arch, rather than the left, develops.
With the aortic arch in this position the ductus arteriosus compresses the oesophagus against the trachea (ligamentum arteriosum).
When the animal consumes solid feed vomiting and regurgitation occur.
Proximal dilation (megaoesophagus) develops due to oesophageal obstruction.
This condition therefore presents as a digestive rather than a circulatory problem.
Miscellaneous cardiac congenital anomalies
Not common
Endocardial fibroelastosis
Portocaval shunts
Endocardial fibroelastosis
Cat.
Burmese and Siamese kittens.
Inherited disease characterised by prominent, white, inelastic, thickened endocardium.
The left ventricle is especially affected with proliferation of fibroelastic tissue.
Left atrium is dilated and left ventricle becomes progressively hypertrophied and dilated.
Portocaval shunts
Dog.
Blood bypass the liver dealing to hyperammonaemia due to failure of hepatic degradation of nitrogenous products.
Neurological signs develop resulting in hepatic encephalopathy.
