How to treat dilated cardiomyopathy in dogs

Disclaimer: This article, its content, and its related references do not constitute veterinary advice and should not be considered a substitute for veterinary care. If your pet is showing any symptoms that could indicate a medical emergency, please seek immediate emergency care.

Dilated cardiomyopathy (DCM), a disease where the heart enlarges as its muscles stretch and grow weak, is one of the most common forms of heart disease in dogs. When the muscles of the heart become loose and floppy, the heart can’t pump blood efficiently, usually leading to congestive heart failure. If you have a dog, read on to learn about:

• Symptoms of dilated cardiomyopathy and heart failure
• How dilated cardiomyopathy in dogs is diagnosed and treated
• What causes dilated cardiomyopathy in dogs
• Which dog breeds are at risk for dilated cardiomyopathy

Treatment for DCM varies depending on the underlying cause, stage of the disease, and presenting symptoms. Clinical signs are often subtle or nonexistent until the affected dog is in heart failure. In some cases, sudden death may occur before the dog is diagnosed. Options for treatment may include diuretics and heart medication, exercise restriction, diet change, and symptomatic treatment. DCM is a complex, multifactorial disease that’s not fully understood in dogs. Many cases can’t be cured, so treatment often focuses on improving heart function and relieving symptoms to provide a better quality of life.

Dilated cardiomyopathy (DCM) is a progressive heart condition in which the heart enlarges as its muscles grow weak and stretch out, reducing the ability of the heart to pump blood efficiently. DCM is one of the most common heart diseases in dogs. Any or all of the four heart chambers can be affected by DCM. The majority of DCM cases in dogs are progressive and incurable, eventually leading to congestive heart failure (CHF). Diet-associated DCM is a less common form that, if caught early, can sometimes be reversed.

Clinical signs of cardiomyopathy and heart failure

Early stages of DCM in dogs can be asymptomatic or show subtle symptoms that are easily overlooked. Symptoms become more severe as the disease progresses and the heart starts to fail. Common symptoms of heart failure in dogs include:

• Coughing
• Shortness of breath or difficulty breathing
• Lethargy
• Exercise intolerance or getting tired quickly
• Loss of appetite
• Rapid breathing at rest
• Abdominal distension
• Pale or blue gums
• Weakness
• Collapse or loss of consciousness
• Sudden death

Symptoms can vary depending on which parts of the heart are affected and what stage the disease is in. Dogs often don’t show obvious symptoms until they’re in heart failure.

When a dog presents with symptoms such as difficulty breathing, exercise intolerance, coughing, or heavy breathing at rest, a vet may suspect DCM. Diagnostic testing is used to confirm or rule out DCM. Recommended diagnostic tests may include:

• Physical exam
• Heart ultrasound (echocardiogram)
• Blood tests, including a heartworm test
• Chest X-rays
• Electrocardiogram (ECG)

It’s important to seek an accurate diagnosis from a veterinarian, as other heart conditions have similar symptoms and may require different methods of treatment.

Dogs who are in respiratory distress may need emergency stabilization before thorough testing and treatment can be completed. Treatment for DCM is often complex and varies between patients depending on the underlying cause, stage of the disease, and presenting symptoms. With the exception of diet-associated dilated cardiomyopathy, DCM in dogs can’t be cured. Instead, treatment focuses on improving heart function, controlling the heart rate and arrhythmias, and relieving other symptoms for as long as possible to improve overall quality of life. Treatment may involve:

• Diuretics and various heart medications
• Exercise restriction
• Diet change or nutritional supplementation
• Manual fluid removal from the chest or abdomen
• Other symptomatic treatment

Since treatment for congestive heart failure is symptomatic and doesn't cure anything, it’s expected to eventually stop working due to the progressive nature of the disease. At this stage, compassionate euthanasia may be the most humane option.

When to seek emergency care

Symptoms associated with DCM also occur with other illnesses, so it’s important to seek care as soon as possible when a dog shows signs of heart disease. “By the time a dog with DCM shows severe symptoms, they are usually in congestive heart failure, which can be rapidly life-threatening,” explains Dr. Jo Myers, a veterinarian on the Vetster platform. “The odds for successful treatment often improve with an earlier time of diagnosis, and it’s also more likely that the medications will work for a longer period of time.”

If your dog has been diagnosed with DCM, talk to your vet about:

• What symptoms to watch for that indicate a need for emergency care
• When and how to adjust medications
• How to observe your dog’s resting respiratory rate, if necessary

Emergency symptoms associated with DCM-induced congestive heart failure include:

• Labored or difficulty breathing
• Blue or pale gums
• Collapse or loss of consciousness

It’s important to seek immediate veterinary care if any of these symptoms are observed, whether your dog has a history of heart disease or not.

Canine DCM can be caused by different issues. The development of DCM in dogs isn’t entirely understood but is likely multifactorial. Some suggested contributing factors for DCM include:

• Genetics
• Nutrition
• Infection
• Chemical exposure

Some breeds of dogs have a higher incidence of DCM, so it’s thought that some cases have a genetic factor. Several nutritional factors are also being studied as potential causes of some cases of DCM in dogs. There have been studies linking grain-free diets to DCM in some dogs; however, the evidence shows that the connection is complex, and feeding grain-free diets does not cause DCM. The relationship between diet and DCM is still being studied, and there’s still more to learn. While many articles claim the link between diet and DCM is a fully understood fact, this is not backed up by evidence. Other diets have also been associated with heart disease in dogs, and not all dogs who eat a grain-free diet develop diet-associated DCM. Finally, infections and parasites that affect the heart may also play a role in developing DCM.

What dogs are most at risk?

Certain dog breeds are predisposed to developing DCM, including:

• Doberman pinschers
• Irish wolfhounds
• Great Danes
• Boxers
• American cocker spaniels
• English bulldogs
• Golden retrievers
• Saint Bernards

Mixed breeds involving these at-risk breeds are also at a higher risk of developing DCM.

Talk to a veterinarian promptly if your dog is showing signs of heart disease. Heart disease is serious, but early detection and intervention is the best way to help an affected dog. Seek emergency care right away if your dog shows any of the following signs:

• Difficulty breathing
• Blue or pale gums
• Collapse or loss of consciousness

These emergency symptoms can be caused by a wide variety of health issues, including heart failure.

You can talk to an online veterinarian if you’re concerned about your dog’s overall risk of developing dilated cardiomyopathy as well as about what long-term treatment may look like if they’ve already been diagnosed. Nutritional consultations are also available if you want to make sure your dog’s food is healthy and not putting them at risk.

Can dilated cardiomyopathy be reversed in dogs?

Dilated cardiomyopathy (DCM) in dogs is usually progressive and incurable. In some cases of diet-associated DCM, the disease can be reversed if caught and treated early enough. Most dogs with DCM eventually develop congestive heart failure, even with aggressive treatment.

What is the best treatment for dilated cardiomyopathy in dogs?

Treatment options for dilated cardiomyopathy (DCM) in dogs vary widely depending on the underlying cause of the disease, how far the disease has progressed, which parts of the heart are affected, and what symptoms the dog has. Treatment may involve cardiac medications, restricting exercise, changing the dog’s diet, removing fluid accumulation in the chest or abdomen, and additional medications for other symptoms.

How long can a dog live with dilated cardiomyopathy?

The prognosis for dilated cardiomyopathy (DCM) in dogs varies between patients depending on the underlying cause, the severity of the disease, the dog’s response to treatment, and which parts of the heart are affected. Some dogs are critically ill by the time they’re diagnosed and succumb quickly, while others may survive weeks, months, or years after the time of diagnosis.