Heart valve dysplasia is a congenital heart

Heart

The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

 defect which affects the aortic, pulmonary, mitral, and tricuspid heart valve

Heart valve

A heart valve normally allows blood flow in only one direction through the heart. The four valves commonly represented in a mammalian heart determine the pathway of blood flow through the heart...

s. Pulmonary valve stenosis

Pulmonary valve stenosis

Pulmonary valve stenosis is a heart valve disorder in which outflow of blood from the right ventricle of the heart is obstructed at the level of the pulmonic valve. This results in the reduction of flow of blood to the lungs. Valvular pulmonic stenosis accounts for 80% of right ventricular outflow...

 and aortic valve stenosis

Aortic valve stenosis

Aortic valve stenosis is a disease of the heart valves in which the opening of the aortic valve is narrowed. The aortic valve is the valve between the left ventricle of the heart and the aorta, which is the largest artery in the body and carries the entire output of blood.-Pathophysiology:The...

 are discussed separately. Dysplasia of the mitral and tricuspid valves can cause leakage of blood or stenosis

Stenosis

A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure.It is also sometimes called a stricture ....

.

Dysplasia of the mitral and tricuspid valves - also known as the atrioventricular (AV) valves - can appear as thickened, shortened, or notched valves. The chordae tendinae

Chordae tendineae

The chordae tendineae, or heart strings, are cord-like tendons that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart....

 can be fused or thickened. The papillary muscle

Papillary muscle

In anatomy, the papillary muscles are muscles located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves via the chordae tendinae and contract to prevent inversion or prolapse of these valves.- Action :There are five total papillary muscles in the heart, three...

s can be enlarged or atrophied

Atrophy

Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations , poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, disuse or lack of exercise or disease intrinsic to the tissue itself...

. The cause is unknown, but genetics

Genetics

Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....

 play a large role. Dogs and cats with tricuspid valve dysplasia often also have an open foramen ovale

Foramen ovale (heart)

In the fetal heart, the foramen ovale , also ostium secundum of Born or falx septi, allows blood to enter the left atrium from the right atrium. It is one of two fetal cardiac shunts, the other being the ductus arteriosus...

, an atrial septal defect

Atrial septal defect

Atrial septal defect is a form of congenital heart defect that enables blood flow between the left and right atria via the interatrial septum. The interatrial septum is the tissue that divides the right and left atria...

, or inflammation of the right atrial epicardium

Epicardium

Epicardium describes the outer layer of heart tissue . When considered as a part of the pericardium, it is the inner layer, or visceral pericardium, continuous with the serous layer....

. In dogs, tricuspid valve dysplasia can be similar to Ebstein's anomaly

Ebstein's anomaly

Ebstein anomaly is a congenital heart defect in which the opening of the tricuspid valve is displaced towards the apex of the right ventricle of the heart.-Presentation:...

 in humans.

Mitral valve stenosis is one of the most common congenital heart defects in cats. In dogs, it is most commonly found in Great Dane

Great Dane

The Great Dane , also known as German Mastiff or Danish Hound , is a breed of domestic dog known for its giant size...

s, German Shepherd Dog

German Shepherd Dog

The German Shepherd Dog , also known as an Alsatian or just the German Shepherd, is a breed of large-sized dog that originated in Germany. The German Shepherd is a relatively new breed of dog, with its origin dating to 1899. As part of the Herding Group, the German Shepherd is a working dog...

s, Bull Terrier

Bull Terrier

The Bull Terrier or English Bull Terrier is a breed of dog in the terrier family. They are known for their large, egg-shaped head, small triangular eyes, and "jaunty gait." Their temperament has been described as generally fun-loving, active and clownish...

s, Golden Retriever

Golden Retriever

The Golden Retriever is a medium-sized breed of dog. They were historically developed as gundogs to retrieve shot waterfowl such as ducks and upland game birds during hunting and shooting parties. As such, they were bred to have a soft mouth to retrieve game undamaged and have an instinctive love...

s, Newfoundland

Newfoundland (dog)

The Newfoundland is a breed of large dog. Newfoundlands can be black, brown, gray, or black and white. They were originally bred and used as a working dog for fishermen in the Dominion of Newfoundland, now part of Canada. They are known for their giant size, tremendous strength, calm dispositions,...

s, and Mastiff

English Mastiff

The English Mastiff, referred to by virtually all Kennel Clubs simply as the Mastiff, is a breed of large dog perhaps descended from the ancient Alaunt through the Pugnaces Britanniae. Distinguishable by enormous size, massive head, and a limited range of colors, but always displaying a black mask,...

s. Tricuspid valve dysplasia is most common in the Old English Sheepdog

Old English Sheepdog

The Old English Sheepdog is a large breed of dog which was developed in England from early herding types of dog. The Old English Sheepdog has very long fur covering the face and eyes...

, German Shepherd Dog, Weimaraner

Weimaraner

The Weimaraner is a dog that was originally bred for hunting in the early 19th century. Early Weimaraners were used by royalty for hunting large game such as boar, bear, and deer. As the popularity of large game hunting began to decline, Weimaraners were used for hunting smaller animals like...

, Labrador Retriever

Labrador Retriever

The Labrador Retriever is one of several kinds of retriever, a type of gun dog. A breed characteristic is webbed paws for swimming, useful for the breed's original purpose of retrieving fishing nets. The Labrador is the most popular breed of dog by registered ownership in Canada, the United...

, Great Pyrenees

Pyrenean Mountain Dog

The Pyrenean Mountain Dog, known as the Great Pyrenees in North America, is a large breed of dog used as a livestock guardian dog.The Great Pyrenees is a very old breed, and has been used for hundreds of years by shepherds, including those of the Basque people, who inhabit parts of the region in...

, and sometimes the Papillon

Papillon (dog)

The papillon , also called the Continental Toy Spaniel, is a breed of dog of the Spaniel type. One of the oldest of the toy Spaniels, it derives its name from its characteristic butterfly-like look of the long and fringed hair on the ears. A papillon with dropped ears is called a phalène...

. It is inherited in the Labrador Retriever.

The disease and symptoms are similar to progression of acquired valve disease in older dogs. Valve leakage leads to heart enlargement, arrhythmias, and congestive heart failure. Heart valve dysplasia can be tolerated for years or progress to heart failure in the first year of life. Diagnosis is with an echocardiogram

Echocardiography

An echocardiogram, often referred to in the medical community as a cardiac ECHO or simply an ECHO, is a sonogram of the heart . Also known as a cardiac ultrasound, it uses standard ultrasound techniques to image two-dimensional slices of the heart...

. There is a poor prognosis

Prognosis

Prognosis is a medical term to describe the likely outcome of an illness.When applied to large statistical populations, prognostic estimates can be very accurate: for example the statement "45% of patients with severe septic shock will die within 28 days" can be made with some confidence, because...

with significant heart enlargement.