An in-depth look at the causes of DCM in dogs, along with diagnostic and treatment approaches that include proper nutrition, supplements, and detoxification.  Dilated cardiomyopathy (DCM) is a serious heart condition that affects dogs and cats. This article will focus on DCM in dogs. The disease is typically characterized by the progressive loss of myocyte numbers and/or function, along with a decrease in cardiac contractility.   DCM primarily affects large and giant breeds that are middle-aged or older (but has been observed in other breeds under specific circumstances, such as taurine deficiency, consumption of unbalanced diets, underlying metabolic or endocrine disorders, chronic myocarditis, or exposure to cardiotoxic substances).     This article explores the causes of DCM, along with diagnostic and treatment approaches, and its controversial connection to grain-free diets (see sidebar on page xx). Preventing or managing DCM in dogs requires assessing risk factors, conducting screenings, and optimizing lifestyle with proper nutrition, supplements, and detoxification.   

Causes of dilated cardiomyopathy in dogs  

Nutritional deficiencies 

Taurine and carnitine deficiencies have been linked to DCM, particularly in breeds such as Golden Retrievers and Cocker Spaniels. These amino acids are critical for healthy cardiac muscle function. Under normal circumstances, dogs efficiently convert methionine and cysteine into taurine. Because dogs can make taurine, it is considered a non-essential amino acid. Essential amino acids are those the body cannot manufacture in sufficient quantities and must be consumed in the diet.  

 Genetic predispositions

DCM often has a genetic basis, with breeds such as Doberman Pinschers, Boxers, Great Danes, and Irish Wolfhounds being predisposed. Genetic mutations can impair cardiac muscle function, resulting in ventricular dilation and compromised contractility.   It is important to recognize that epigenetic factors, such as environmental influences, diet, stress, and toxin exposure, are critical in the development of “dis-ease.” These factors can also influence gene expression, potentially triggering or mitigating the development of DCM in genetically predisposed dogs.  

Low taurine levels 

The ability to synthesize taurine relies on adequate dietary intake of the precursor amino acids methionine (an essential amino acid) and cysteine. However, several factors can disrupt this balance:1   

• Low levels of methionine and cysteine in the diet: Some grain-free diets, particularly those high in legumes and tubers, may lack sufficient amounts of these amino acids.2 

• Reduced bioavailability: High dietary fiber can interfere with the absorption of amino acids, diminishing the precursors available for taurine synthesis.  

• Increased fecal loss of taurine: Certain dietary components such as high-fiber ingredients (especially from legumes like peas and lentils), poorly digestible proteins, and diets low in sulfur-containing amino acids, alter the gut microbiota or interfere with bile acid recycling. This leads to greater excretion of taurine and can contribute to deficiency, even in dogs consuming adequate dietary protein.3 

• Breed-specific metabolic differences: Some breeds, like Golden Retrievers, may have inherently lower taurine synthesis rates, making them more susceptible to deficiencies.4 

Environmental and secondary factors contributing to DCM 

Toxins, infections, and several systemic diseases can contribute to dilated cardiomyopathy in dogs by causing chronic stress on the heart or impairing its function. Key contributors include:   

• Endocrine disorders: Hypothyroidism and diabetes mellitus can reduce cardiac output, leading to stress on the heart and inflammation, which may contribute to DCM. 

• Infectious or inflammatory diseases: Myocarditis, caused by viral or bacterial infections, can damage the heart muscle and worsen the progression of DCM. 

• Autoimmune diseases: Conditions like lupus and polymyositis can lead to heart inflammation, placing additional strain on the heart and potentially exacerbating DCM. 

• Nutritional deficiencies: Inadequate intake of essential nutrients like protein, vitamin E, and selenium can weaken heart function and contribute to DCM. 

• Respiratory issues: Chronic respiratory diseases and hypoxia (lack of oxygen) increase the burden on the heart, potentially accelerating the development of DCM. 

• Kidney and liver diseases: Chronic kidney and liver insufficiency can cause metabolic imbalances, which may negatively impact cardiac health and contribute to DCM. 

• Chronic inflammation: Conditions like periodontal disease or obesity-related inflammation can lead to systemic stress, potentially worsening DCM.  

Managing these underlying systemic conditions is crucial for the prevention or management of DCM in dogs.   

Diagnosing DCM in dogs 

  Early detection is crucial for effective management. Predisposed breeds should have a cardiac workup (including X-rays, ECHO, ECG) starting at three years of age, and be monitored yearly.    Clinical signs Early symptoms may go undetected because as cardiac contractility begins to fail, leading to decreased cardiac output, the Renin-Angiotensin-Aldosterone System (RAAS) activates to create homeostasis with blood pressure and fluid balance, ensuring proper blood volume and electrolyte levels.     Over time, this excessive activation of the RAAS causes continued retention of sodium and water even in the face of edema or effusion. Once symptoms become evident, they can include lethargy, coughing, difficulty breathing, fainting, and exercise intolerance.    Imaging and testing 

• Echocardiography (ultrasound of the heart): The gold standard for diagnosing DCM. It reveals ventricular dilation and impaired contraction. 

• Electrocardiography (ECG): Detects arrhythmias, which are common in DCM cases. 

• Radiographs (X-rays): Assess heart size and detect fluid buildup in the lungs. 

• Blood tests: NT-proBNP levels (a cardiac biomarker) and taurine levels can support diagnosis and guide treatment. 

Standard Western approach to DCM 

  Medications 

• ACE Inhibitors (e.g. enalapril, benazepril): Reduce workload on the heart by lowering blood pressure. Common side effects: Lethargy or weakness, low blood pressure (hypotension) and kidney dysfunction (elevated BUN/creatinine) 

• Diuretics (e.g. furosemide): Manage fluid accumulation associated with heart failure. Common side effects: Increased urination, electrolyte imbalances (e.g., low potassium) and dehydration. 

• Beta-blockers (e.g. carvedilol): Help regulate heart rhythm and reduce strain on the heart. Common side effects: Slowed heart rate (bradycardia), fatigue or weakness and low blood pressure. 

  Nutritional support Supplementing taurine and carnitine, even in cases where deficiencies are not confirmed, is a standard approach for nutritional management.   Lifestyle adjustments Exercise restriction is often recommended to reduce cardiac workload.   

Integrative approach to DCM 

  Integrative medicine combines conventional treatments with holistic approaches (whole body) to optimize outcomes for dogs with DCM.     Dietary improvements   

• A species-appropriate grass fed/finished, free range or wild caught diet provides high biological value. Focus on high-quality, bioavailable proteins and healthy fats to support overall health, including heart health. These provide the building blocks for muscle function, including the heart muscle. 

• Digestive enzymes, including pancreatic enzymes, assist in the breakdown of proteins to enhance nutrient absorption and digestion. 

• Supporting gut health facilitates the uptake of amino acids by healing the gut and promoting a balanced microbiome. 

• Supplementing with essential vitamins, minerals, fatty acids, and amino acids ensures adequate intake of these nutrients to support overall body function, including heart health. 

• Reducing inflammation includes limiting inflammatory foods like processed grains and high-carb diets to reduce stress on the cardiovascular system and improve heart function. Omega-3 fatty acids (EPA and DHA) offer cardioprotective and anti-inflammatory benefits.  

  Targeted supplementation   

• Taurine and carnitine: Taurine is an essential amino acid critical for heart health. In some dogs, taurine deficiency can contribute to the development of DCM. Supplementing with taurine, along with carnitine (another amino acid that supports fat metabolism), can help improve cardiac function and prevent further damage.  

• Coenzyme Q10 (CoQ10): Also called ubiquinol, CoQ10 refers to the same antioxidant compound, but they exist in two different forms. CoQ10 is the oxidized version, while ubiquinol is the reduced form. 

• CoQ10 is a naturally occurring antioxidant found throughout the body, particularly in the mitochondria, where it plays a key role in energy production. CoQ10 supports cellular processes that generate energy, especially in high-energy organs like the heart. 

• Ubiquinol is the reduced form of CoQ10, meaning it has gained electrons and is in a more active state, making it a potent antioxidant. Ubiquinol is crucial for neutralizing free radicals and protecting cells from oxidative damage. 

  The key structural difference is that CoQ10 has a double bond, making it oxidized, while ubiquinol has an additional hydrogen atom, making it reduced. In the body, CoQ10 can be converted into ubiquinol, and vice versa, depending on the body’s needs for antioxidant protection or energy production. For example, when the body needs more antioxidants, CoQ10 is converted into ubiquinol to provide that support.    CoQ10 and ubiquinol are vital for mitochondrial function, which is essential for energy production, especially in heart cells. Supplementing with CoQ10 or ubiquinol can improve heart muscle function and overall vitality by ensuring the heart’s cells have the energy they need to operate efficiently.   

• Magnesium and potassium testing: It’s important to regularly test magnesium and potassium levels, as these minerals play a critical role in heart health. Magnesium is essential for the proper function of the heart muscle and helps regulate electrical impulses that control heart rhythm.  

  Potassium is equally vital for maintaining cellular function and fluid balance within the heart. Deficiencies in either of these minerals can significantly contribute to arrhythmia or exacerbate heart failure. Ensuring optimal levels through testing and appropriate supplementation is an important part of supporting overall cardiac health.    Alternative therapies to complement an integrative approach to DCM     

• Acupuncture stimulates specific points along the body’s energy pathways, supporting circulation, reducing inflammation, and promoting balance within the body. This therapy can improve heart function by increasing blood flow, supporting the nervous system, and reducing stress, which is beneficial for a dog with heart disease. 

• Massage therapy can improve blood flow, reduce muscle tension, promote relaxation, and help decrease stress. For dogs with DCM, massage helps improve circulation, supports lymphatic drainage, and reduces the overall strain on the cardiovascular system.5 

• Assisted lymphatic therapy promotes the efficient drainage of lymphatic fluid, which helps detoxify the body and reduce fluid buildup. For dogs with heart disease, lymphatic drainage can be particularly useful in managing fluid retention, which is a common symptom of heart failure. Caution must be used to not overburden the blood stream with extra lymphatic input. Assisted lymphatic therapy also supports immune function and helps alleviate congestion in the lymphatic system.  

• Fascia decompression therapy targets the connective tissues surrounding muscles and organs, helping to release tension, reduce tightness, improve energy flow and improve mobility. This can be particularly beneficial for dogs with DCM, as it helps relieve strain in the body that may exacerbate cardiovascular stress. By promoting relaxation and improved tissue flexibility, fascia release helps support the immune system, overall physical comfort and heart health.  

• Hyperbaric oxygen therapy (HBOT) increases the oxygen supply to the body’s tissues, including the heart. It enhances healing, reduces inflammation, and promotes tissue repair. For dogs with DCM, HBOT can help improve oxygen delivery to the heart and other vital organs, supporting recovery and potentially slowing disease progression. 

   The alarming rise in chronic degenerative “dis-eases” affecting pets (and humans) is sending a clear message: what we are doing is not working! As Einstein said, we cannot solve problems with the same mindset that created them. Our fast, cheap and convenient lifestyle filled with processed foods and toxins must change to a sustainable model for people, pets and the planet.     By embracing a holistic, integrative approach, we have the opportunity to not only treat conditions like DCM more effectively but also to enhance the overall well-being of our pets. This shift allows us to move towards a more proactive, mindful way of supporting health and emphasizing prevention, nourishment, and healing in ways that honor the natural processes of the body. Let’s take this opportunity to explore all available options, from conventional to integrative, to offer the best possible care for our patients.  Potential connection between DCM and grain-free diets  Recent attention has focused on the potential role of grain-free diets in DCM. These diets often substitute grains with legumes (such as peas and lentils) and tubers (like potatoes). While these ingredients can meet basic nutritional requirements, they may inadvertently contribute to taurine deficiency through the mechanisms mentioned in the article.   Studies have documented cases where dogs on grain-free diets developed DCM linked to taurine deficiency. Notably, many of these dogs showed improvement in cardiac function after dietary adjustments and taurine supplementation.   The role of grain-free diets in DCM has sparked widespread debate. The FDA and veterinary researchers have investigated reports of dogs developing DCM while consuming diets high in legumes, peas, and lentils. While the exact mechanisms remain under investigation, some evidence suggests these ingredients may interfere with taurine absorption or synthesis. Proposed mechanisms include:   

1. Reduced taurine bioavailability

Legumes may alter gut microbiota or bind taurine precursors, leading to reduced absorption or synthesis.   

2. Dilution of essential nutrients

Diets heavy in plant-based ingredients lack sufficient meat-based protein, a critical taurine source.    Detoxification and removal of toxins    To develop a targeted treatment plan, testing for nutritional deficiencies and toxicities is crucial. Blood tests, hair analysis, and urine samples can be used to assess these levels. Once deficiencies or toxicities are identified, supplementation and detox strategies can be employed to correct imbalances. 

References 

  atlantaskinvet.com    Freeman LM, et al. “Diet-associated dilated cardiomyopathy in dogs: what do we know?” Journal of the American Veterinary Medical Association (2021).    Lionscourt Leonbergers. “DCM and the Leonberger.” lionscourt.org.    Martin MWS, et al. “Canine dilated cardiomyopathy: a retrospective study of prognostic findings in 367 clinical cases.” Journal of Small Animal Practice (2010).  merckvetmanual.com/circulatory-system/cardiomyopathy-in-dogs-and-cats/dilated-cardiomyopathy-in-dogs-and-cats.    Pion PD, et al. “Taurine deficiency and dilated cardiomyopathy in dogs.” Journal of the American Veterinary Medical Association (1998).    PubMed Central (PMC), National Institutes of Health. Relevant peer-reviewed studies on DCM and taurine metabolism. ncbi.nlm.nih.gov/pmc.    U.S. Food & Drug Administration. “FDA Investigation into Potential Link between Certain Diets and Canine Dilated Cardiomyopathy.” Retrieved from FDA.gov.    University of California. “Dogs on some popular grain-free diets could be at risk of heart disease.” universityofcalifornia.edu/news/dogs-some-popular-grain-free-diets-could-be-risk-heart-disease.