Dilated Cardiomyopathy

What is dilated cardiomyopathy, and what does this diagnosis mean for your pet? Knowing about the condition and how it affects your pet goes a long way in helping your family cope with a diagnosis of heart disease, and can also help you provide your beloved pet with the best care and quality of life. Dilated cardiomyopathy, also referred to as DCM, is a disease that does not develop until your pet is an adult. The breeds most commonly affected by DCM are the Doberman and other large- to giant-breed dogs, but it can also develop in medium-sized dogs, such as the Cocker Spaniel.

If your pet is a large- or giant-breed, or is otherwise susceptible to DCM, the best thing you can do as an owner is to talk to your regular veterinariand and request a referral to a Board-Certified Cardiologist or Internist and have your pet examined. Your pet will receive the best of care, and you, as the owner, will receive the best information on the most advanced treatments and diagnostics. Our ExpertVet certified practice veterinarians can help answer your questions and offer state-of-the-art treatment options for your dog. 

Whenever your pet is showing signs of a health issue your first step is to contact your primary care veterinarian. If it is indicated that your pet may suffer from dilated cardiomyopathy or another serious condition, a veterinary specialist is available at an ExpertVet certified hospital.


The heart is a muscle that is divided into four chambers that work together to pump blood to the lungs, where it receives oxygen, and then to the rest of the body. To do this effectively and deliver nutrient-carrying blood to the body’s tissues, the heart must be strong and contraction of the chambers well-coordinated. DCM is characterized by dilated heart chambers, a thin and weak heart muscle, and a decreased ability of the heart muscle to contract. All of this results in the heart being less able to pump blood throughout the body. This condition is known in medical terms as systolic dysfunction.

Systolic dysfunction alone does not mean your dog has DCM.  It can result from a deficiency of taurine, which is an amino acid. It can be caused by the inflammation or infection of the heart muscle, which is called myocarditis. There are other causes of systolic dysfunction that are hard to diagnose so do not automatically think “DCM” if your dog’s heart is not able to pump blood throughout the body the way it should. Your Board-Certified Veterinarian will be able to explain to you what is causing your pet’s problems.

Early, asymptomatic (also called occult) DCM is the earliest stage of DCM that can be diagnosed. Occult DCM progresses slowly. Unfortunately, even once this disease has been diagnosed and treated with medications, it is still expected that your pet’s DCM will progress, and signs of heart failure will start to develop in 1 to 2 years. The good news, though, is that early detection and medical treatment can delay the onset of symptoms of DCM and prolong your pet’s survival.

DCM is a progressive disease that can be managed with medication but cannot be cured. Patients with DCM often experience increasing weakness, lethargy, and weight-loss and are at risk for congestive heart failure (fluid build-up in the lungs or in the abdomen). Sadly, it is a possibility that your pet could die suddenly as a result of abnormal heart rhythms (arrhythmias) caused by DCM.


It can be challenging to diagnose DCM because your pet may not show any abnormalities upon physical examination by the veterinarian. A heart murmur (caused by a leaky heart valve) may be noticed; however this is frequently not present. There also may be quiet, but other abnormal heart sounds, such as a gallop sound or an arrhythmia noticed.

Chest radiographs (x-rays) usually do not show a significant enlargement of the heart in the early stages of DCM, allowing it to go unnoticed. The best way to diagnose DCM is by referral to a cardiologist for an echocardiogram (ultrasound of the heart) to determine whether a heart chamber is enlarged and to see whether the heart is functioning correctly. A holter monitor (24-hour ECG) is also recommended to evaluate for intermittent arrhythmias that may not show up during your pet’s examination.

Other diagnostic measurements, such as a blood pressure readings or laboratory blood work may be recommended to further evaluate your pet for other diseases or factors that may complicate the management of DCM. If systolic dysfunction is present in a breed in which DCM is not normally seen (atypical breed), blood tests to determine taurine levels, thyroid levels, and infectious disease screening may be recommended. Tell your Board-Certified veterinarian if you are concerned that your pet might have DCM and need further testing.