The prevalence of congenital heart disease is estimated to be 1% of the canine population. Congenital defects are often recognised by the finding of an incidental murmur when a pup is presented for vaccination. While the owner of a new pet needs a diagnosis and prognosis, such advice on the basis of clinical examination alone is fraught with problems; in many cases detailed and expensive investigations to provide a diagnosis may not suit the owner's requirements.

A degree of certainty as to the diagnosis can be obtained from the combined information that clinical examination, the breed, an ECG and thoracic radiography provide. However, definitive diagnosis depends on echocardiographic examination with Doppler. Additionally, since there is a wide spectrum of severity in congenital defects, the most accurate prognosis can be offered in most cases by echo-Doppler. An exception is PDA which has a fairly characteristic murmur, and, if diagnosed and surgically corrected early, carries an excellent prognosis.

However, murmurs can be missed and it is not until clinical signs develop that heart disease is found. In some cases clinical signs might not appear until adulthood, when an acquired heart disease is usually considered and congenital causes are low on the differential list.

This chapter reviews the more common congenital heart defects. For a more extensive review the reader is referred to the References and Further Reading section.

   PATENT DUCTUS ARTERIOSUS
  AORTIC STENOSIS
  PULMONIC STENOSIS
  VENTRICULAR SEPTAL DEFECT (VSD)
  ATRIOVENTRICULAR VALVE DYSPLASIA
  TETRALOGY OF FALLOT
  ATRIAL SEPTAL DEFECT

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