Enlarged Heart (Dilated Cardiomyopathy) in Dogs

DCM primarily affects the lower left chamber of the heart (left ventricle), which pumps blood from the lungs to the body, although it can also affect the right side.

Dogs with a cough, weight loss and decreased energy should be evaluated promptly. Difficulty breathing, collapse, sudden weakness, or fainting in dogs is an emergency.

DCM is the second most common type of heart disease in dogs and large breed dogs are predisposed.

In recent years there has been a great deal of reporting and public interest in whether DCM is directly correlated with nutritional deficiencies in dogs. In particular there has been concern that DCM is associated with speciality diets such as grain-free or legume-based protein formulations. Research is ongoing and more information is needed to fully understand the relationship between grain-free and legume-based diets and DCM in dogs. Feeding a well balanced, vet recommended diet is considered the best standard for avoiding nutrient deficiencies.

DCM, in most cases, progresses to congestive heart failure (CHF).

• Idiopathic (unknown)
• Nutritional factors, in particular taurine deficiency
• Genetic
• Chemical/toxin exposure, including Doxorubicin and Epirubicin
• Infectious disease (rare) including parvovirus and lyme disease
• Parasitic (rare) including Trypanosomiasis

DCM diagnosis starts with a full physical exam. X-rays may be done to visualize an enlarged heart and/or fluid in or around the lungs. Echocardiogram (ultrasound of the heart) is required to definitively diagnose DCM. Blood tests may be done to identify underlying problems with nutrition or infection. From there, an electrocardiogram (EKG) or a 24-hour EKG (Holter monitor) may be indicated.

Treatment may be complex, involving several types of medications used to increase the heart’s ability to pump blood effectively and treat any arrhythmias. Nutritional supplementation and/or diet change may be indicated. To relieve discomfort, fluid removal procedures may be used on the chest or abdomen.

DCM is a progressive disease, so the prognosis depends on the stage of disease when identified.

Prognosis for diet-associated DCM cases is fair to good, as nutritional changes may reverse the disease process. DCM is more often progressive and incurable, and by the time signs of heart failure are evident, the long-term prognosis is poor and survival time is 6-24 months on average. Left-sided heart failure, which is more common with DCM, carries a worse prognosis than right-sided.

There is no specific prevention for DCM. Ensuring complete and balanced nutrition may be helpful and is recommended in any case. In addition, screening is available to pet parents and breeders of dogs that are predisposed to DCM. Neutering dogs with DCM prevents genetic transmission.

DCM is the second most common heart disease of dogs. Large and giant breed dogs are predisposed, as are certain specific breeds.

Depending on the case, treatment may include: Medications

• Inotropes
• Antiarrhythmics
• Diuretics
• Vasodilators
• ACE inhibitors
• Palliative care
• Diet change
• Nutritional supplementation