Heart valve dysplasia is a congenital

heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...

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

heart valve A heart valve is a one-way valve that allows blood to flow in one direction through the chambers of the heart. Four valves are usually present in a mammalian heart and together they determine the pathway of blood flow through the heart. A heart v ...

s. Dysplasia of the mitral and tricuspid valves can cause leakage of blood or

stenosis A stenosis (from Ancient Greek στενός, "narrow") is an abnormal narrowing in a blood vessel or other tubular organ or structure such as foramina and canals. It is also sometimes called a stricture (as in urethral stricture). ''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 The chordae tendineae (tendinous cords), colloquially known as the heart strings, are inelastic cords of fibrous connective tissue that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart. Structure The chorda ...

can be fused or thickened. The

papillary muscle The papillary muscles are muscles located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae and contract to prevent inversion or prol ...

s can be enlarged or atrophied. The cause is unknown, but

genetics Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar wor ...

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

atrial septal defect Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria (upper chambers) of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this d ...

, or inflammation of the right atrial

epicardium The pericardium, also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. It has two layers, an outer layer made of strong connective tissue (fibrous pericardium), and an inner layer made of ...

. In dogs, tricuspid valve dysplasia can be similar to

Ebstein's anomaly Ebstein's anomaly is a congenital heart defect in which the septal and posterior leaflets of the tricuspid valve are displaced towards the apex of the right ventricle of the heart. It is classified as a critical congenital heart defect accounting ...

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 The Great Dane is a large sized dog breed originating from Germany. The Great Dane descends from hunting dogs from the Middle Ages used to hunt wild boar and deer, and as guardians of German nobility. It is one of the largest breeds in the world ...

German Shepherd Dog The German Shepherd or Alsatian is a German breed of working dog of medium to large size. The breed was developed by Max von Stephanitz using various traditional German herding dogs from 1899. It was originally bred as a herding dog, for he ...

Bull Terrier The Bull Terrier is a breed of dog in the terrier family. There is also a miniature version of this breed which is officially known as the Miniature Bull Terrier. Appearance The Bull Terrier's most recognizable feature is its head, described ...

Golden Retriever The Golden Retriever is a Scottish breed of retriever dog of medium size. It is characterised by a gentle and affectionate nature and a striking golden coat. It is commonly kept as a pet and is among the most frequently registered breeds ...

Newfoundland Newfoundland and Labrador (; french: Terre-Neuve-et-Labrador; frequently abbreviated as NL) is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region ...

s, and

Mastiff A mastiff is a large and powerful type of dog. Mastiffs are among the largest dogs, and typically have a short coat, a long low-set tail and large feet; the skull is large and bulky, the muzzle broad and short (brachycephalic) and the ears dro ...

s. Tricuspid valve dysplasia is most common in the

Old English Sheepdog The Old English Sheepdog is a large breed of dog that emerged in England from early types of herding dog. Obsolete names for the breed include Shepherd's Dog and . The nickname ''Bob-tail'' (or ''Bobtail'') originates from how dogs of the breed ...

, German Shepherd Dog,

Weimaraner The Weimaraner ( ) is a large dog that was originally bred as a hunting dog 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 d ...

, Labrador Retriever,

Great Pyrenees The Pyrenean Mountain Dog (french: Chien de Montagne des Pyrénées) is a breed of livestock guardian dog from France, where it is commonly called the Patou. The breed comes from the French side of the Pyrenees Mountains that separate France an ...

, and sometimes the Papillon. 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,

arrhythmia Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adults ...

s, and

congestive heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...

. Heart valve dysplasia can be tolerated for years or progress to heart failure in the first year of life. Diagnosis is with an

echocardiogram An echocardiography, echocardiogram, cardiac echo or simply an echo, is an ultrasound of the heart. It is a type of medical imaging of the heart, using standard ultrasound or Doppler ultrasound. Echocardiography has become routinely used in th ...

. The

prognosis Prognosis (Greek: πρόγνωσις "fore-knowing, foreseeing") is a medical term for predicting the likely or expected development of a disease, including whether the signs and symptoms will improve or worsen (and how quickly) or remain stabl ...

is poor with significant heart enlargement.

References

Dog diseases Cat diseases Valvular heart disease {{Veterinary-med-stub