Causes of Dilated Cardiomyopathy
The causes of dilated cardiomyopathy (DCM) are not known. The medical term for this is “idiopathic”. A number of different things have been suggested as possible contributors to the disorder. These include malnutrition (dietary deficiencies in taurine [a sulfur-containing essential fatty acid] and/or carnitine [a co-enzyme of fatty acid oxydation), immune-mediated abnormalities, viral infection, protozoal infection, microvascular hyperreactivity and genetic disorders involving specific myocardial (heart muscle) structural or contractile proteins. Hypothyroidism and myocarditis have also been associated with DCM in domestic dogs. In rare cases, DCM is accompanied by bacterial infection or exposure to some toxic substance.
There is no reported way to prevent dilated cardiomyopathy from developing in dogs. Given the suspected hereditary component, affected dogs certainly should not be used as part of a responsible breeding program. Many authorities suggest that the parents of dogs with DCM not be bred again – at least not to each other. Some experts recommend that even unaffected littermates of affected animals should not be bred.
DCM is usually seen in middle-aged to older dogs, with the exception of Portuguese Water Dogs, which tend to develop a juvenile version of the disease that becomes apparent very early-on, typically by several weeks to several months of age. DCM is the most common cause of congestive heart failure in large and giant breed dogs. However, it is fairly uncommon in toy and small breeds.