It is a lethal, incurable disease of genetic and hereditary origin, which consists of the dilation and loss of thickness and strength of the myocardium, which gradually loses its ability to pump blood, causing and respiratory failure. It usually appears between the ages of 4 and 10, although it can appear earlier or later. Symptoms include exercise intolerance, loss of appetite, coughing, panting, ascites (abdominal swelling). It may come on abruptly or cause sudden death. From the moment it appears, life expectancy is short, but, if detected early, appropriate therapy can increase it by up to four years.

 

It is, therefore, important, for both breeders and owners, to carry out regular, biannual screenings - in the second case to, with an early diagnosis, try to delay the progression of the disease and improve the dog's quality of life and, in the first case, also to try to prevent affected dogs from being used as breeding stock. ​ It is common in large and medium breeds. In Prof. Luís Lima Lobo's PhD research on the disease in the Estrela Mountain Dog, carried out between 2004 and 2009, 20% of the specimens that participated were affected.