Canis ISSN: 2398-2942

Heart: tricuspid valve dysplasia

Synonym(s): Atrioventricular valve dysplasia

Contributor(s): Josephine Dandrieux, Mark Oyama, Liz Bode


  • TVD is a congenital defect of the tricuspid valve and its related structures (ie papillary muscles and chordae tendineae).
  • It is an uncommon congenital heart disease in dogs, accounting for 2% of all congenital conditions in one study. TVD is most often detected in large breed dogs, and in particular, the Labrador Retriever Retriever: Labrador. TVD is occasionally seen in cats.
  • TVD causes tricuspid regurgitation, right heart enlargement, and in severe cases, right heart failure.
  • Signs: asymptomatic murmur in many cases and animals can remain asymptomatic for years. In more severe cases right sided heart failure may develop and then common clinical signs include abdominal distension, jugular pulsation, weakness, and poor appetite. 
  • Treatment: involves standard medical therapy for heart failure.
  • Prognosis: poor in severely affected animals.



  • TVD causes varying degrees of tricuspid regurgitation, right heart volume overload and enlargement, and right-sided congestive heart failure.
  • TVD includes a spectrum of anatomical lesions including focal or diffuse thickening or shortening of the valve leaflets, focal agenesis of the valve, shortened chordae tendineae, incomplete separation of the valve leaflets from the ventricular or septal wall, malpositioned and underdeveloped of the papillary muscles, fenestrations of the valve leaflets, and varying degrees of concurrent valve stenosis.
  • The genetic etiology of TVD in Labradors has been located to a defective gene on chromosome 9 and is a heritable disorder.
  • In a population of Douge de Bordeaux the mode of inheritance was thought to be autosomal recessive.


  • TVD causes tricuspid regurgitation and progressive right-sided eccentric hypertrophy. As the right ventricle and atrium dilates, the annulus of the tricuspid valve orifice increases, and due to the inability of the defective valves to cover this increasing area, the degree of regurgitation worsens. Inasmuch as this cycle perpetuates itself, the degree of volume overload continues to increase. As the amount of regurgitation increases, forward right ventricular stroke volume can fall and lead to decreased venous return into the left heart. Activation of the renin-angiotensin-aldosterone (RAAS) system contributes to right-sided heart failure, usually manifest as ascites.


  • Many dogs and cats with severe TVD can remain symptom free for many years. Only after a protracted period of progressive heart enlargement do animals present with clinical signs. By this time, their hearts are often extremely dilated.
  • Many dogs and cats that finally present with clinical signs are in the end-stages of their disease, and therefore prognosis is very poor.


  • TVD is a heritable defect in the dog, and affected dogs should not be bred Congenital heart disease: overview.
  • Closely related dogs may benefit from cardiac examination.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Schrope D P (2015) Prevalence of congenital heart disease in 76,301 mixed-breed dogs and 57,025 mixed-breed cats. J Vet Cardiol 17 (3), 192-202 PubMed.
  • Ohad D G, Avrahami A, Waner T & David L (2013) The occurrence and suspected mode of inheritance of congenital subaortic stenosis and tricupid valve dysplasia in Dogue de Bordeaux dogs. Vet J 197 (2), 351-357 PubMed.
  • Famula R, Siemens M, Davidson A P, Packard M (2002) Evaluation of the genetic basis of tricuspid valve dysplasia in Labrador Retrievers. Am J Vet Res 63 (6), 816-20 PubMed.
  • Oyama M A, Sisson D D (2001) Evaluation of canine congenital heart defects using an echocardiographic algorithim. J Am Anim Hosp Assoc 37 (6), 519-35 PubMed.
  • Hoffmann G, Amberger C N, Seiler G, Lombard C W (2000) Tricuspid dysplasia in fifteen dogs. Schwiez Arch Tierheilkd 142 (5), 268-77 PubMed.
  • Kornreich B G, Moïse N S (1997) Right atrioventricular valve malformation in dogs and cats: an electrocardiographic survey with emphasis on splintered QRS complexes. J Vet Intern Med 11 (4), 226-30 PubMed.
  • deMadron E, Kadish A, Spear J F, Knight D H (1987) Incessant atrial tachycardias in a dog with tricuspid dysplasia.Clinical management and electrophysiology. J Vet Intern Med (4), 163-169 PubMed.
  • Liu S K, Tilley L P (1976) Dysplasia of the tricuspid valve in the dog and cat. JAVMA 169 (6), 623-630 PubMed.

Other sources of information

  • Fox P R, Sisson D D, Moise N S (eds) (1999) Textbook of Canine and Feline Cardiology. 2nd edn. W B Saunders, Philadelphia.
  • Kittleson M D, Kienle R D (1998) Small Animal Cardiovascular Medicine. Mosby, St. Louis.