Dilated Cardiomyopathy in Dogs

Dilated cardiomyopathy (DCM) is a condition characterised by the degeneration of the heart muscle, leading to thinning and weakening of the muscle walls, particularly in the left ventricle. This weakening impairs the heart's ability to effectively pump blood, resulting in congestion within the heart and subsequent dilation of its chambers. As the disease progresses, dogs may develop murmurs due to stretched heart valves and abnormal heart rhythms. While DCM can affect various breeds, it is most commonly observed in larger breeds such as boxers, doberman pinschers, Great Danes, and Saint Bernards, with male dogs being more frequently affected than females.

Signs and Symptoms of DCM

Signs of DCM can manifest suddenly or gradually over time. Monitoring your dog for the following symptoms can help detect the condition early:

• Rapid breathing, especially when resting or sleeping (more than 30-35 breaths per minute)

• Increased effort associated with breathing

• Restless sleeping, frequent position changes

• Coughing or gagging

• Weakness and reduced ability to exercise

• Collapse or fainting episodes

• Decreased appetite and weight loss

• Abdominal swelling

• Depressed demeanor or decreased interaction

• Sudden death in severe cases

If you notice any of these signs in your dog, it is essential to seek veterinary attention promptly for a thorough evaluation.

Diagnosis and Treatment

Diagnosing DCM involves a combination of tests to assess heart function comprehensively:

• Auscultation: Listening to heart sounds and assessing murmurs

• Blood and urine tests: Evaluating liver and kidney function

• Cardiac biomarkers: Measuring specific proteins indicating heart disease

• Chest radiographs (X-rays): Examining heart size and lung condition

• Electrocardiogram (ECG): Assessing heart rhythm and rate

• Ultrasound examination (echocardiogram): Imaging the heart chambers and walls

Once diagnosed, treatment aims to manage symptoms and improve heart function. This typically involves a combination of medications, including:

• Pimobendan: Improves heart muscle strength and blood flow

• Diuretics: Remove excess fluid from the body

• ACE inhibitors: Lower blood pressure and reduce heart workload

• Cardiac glycosides: Enhance heart function and regulate heart rate

• Anti-arrhythmic drugs: Control abnormal heart rhythms

Dietary adjustments and nutritional supplements may also be recommended, especially in breeds with specific dietary considerations.

Diet-Associated Dilated Cardiomyopathy

In recent years, there has been a rise in cases of diet-associated dilated cardiomyopathy (DCM) in dogs, with concerns about certain dietary factors contributing to the condition. Previously, diets containing lamb and rice, low protein, and high fiber were linked to DCM, primarily affecting specific breeds. However, atypical breeds are now being diagnosed.

While some cases are associated with taurine deficiency, others with normal taurine levels have been noted, especially in dogs fed diets rich in lentils, peas, or grain-free formulations.

Ongoing research explores various factors, including ingredient bioavailability and breed-specific predispositions. Given the challenges of diagnosing DCM, veterinarians must remain vigilant, using thoracic radiographs and echocardiograms for evaluation. Pet owners are advised to discuss dietary choices with their veterinarians, considering the risks and benefits, while professionals stay updated on emerging research.

You can find more information here.

Prognosis and Monitoring

The prognosis for dogs with DCM varies depending on factors such as breed, disease stage at diagnosis, and response to treatment. While some dogs may respond well to therapy and enjoy an improved quality of life, others may experience a more rapid decline. Regular follow-up appointments with your veterinarian are crucial for monitoring your dog's condition and adjusting treatment as needed.

When to See Your Veterinarian

If you observe any concerning signs or symptoms suggestive of heart disease in your dog, such as coughing, laboured breathing, or exercise intolerance, it is essential to schedule a veterinary examination promptly. Early detection and intervention can significantly impact the outcome and quality of life for dogs with DCM.

By staying vigilant and proactive about your dog's health, you can help identify potential issues early and provide the necessary support to ensure their well-being.

Medically reviewed by Dr. Kirra Balmanno

If you suspect that your dog may have DCM or if they’ve been diagnosed and you have questions or concerns, you can book an appointment online with one of our veterinarians, here to answer any questions you have.