Understanding and Properly Treating Heart Problems in Dogs

The heart plays a vital role in our dogs' organisms. Similar to humans, dogs can also be susceptible to heart diseases. These can either be congenital or develop over the course of a dog's life. It is therefore important for dog owners to know the possible signs of heart disease and to take necessary precautions to maintain the heart health of their loyal companions and help them lead long and happy lives.

How Does the Heart Work?

The heart is a large muscle that functions as a pump, ensuring that blood is transported throughout the body. It consists of a left and right atrium and a left and right ventricle. In the lungs, the blood is enriched with oxygen. From there, it flows into the left atrium and then into the left ventricle, which pumps the oxygen-rich blood throughout the body, supplying all organs, muscles, and the brain with oxygen. From the body, the now oxygen-poor blood enters the right atrium, from there into the right ventricle, which in turn pumps the blood to the lungs, where it is again enriched with oxygen. In this circulatory system, heart valves ensure that blood flows in only one direction. They function like valves that open when the heart contracts and close when the heart relaxes, thereby preventing blood from flowing backward.  

What are the Most Common Heart Diseases?

Among the many different heart diseases that can affect dogs, the two most common are dilated cardiomyopathy and mitral valve insufficiency.

In dilated cardiomyopathy, the heart muscle, also called the myocardium, loses its ability to pump blood efficiently due to degeneration. This leads to an enlargement of the heart chambers, reduced effectiveness of contractions, and rhythm disturbances, thereby impairing overall heart function. This disease often progresses relatively quickly and can, under certain circumstances, lead to sudden cardiac death without prior symptoms of heart failure being visible.

Mitral valve insufficiency (also called degenerative endocardiosis of the mitral valves) is the most common heart disease in dogs. It involves deformities and thickening of the valve between the left atrium and the left ventricle. As a result, it can no longer close properly, leading to a backflow of blood in the wrong direction. Over time, the atrium and ventricle enlarge, and the pumping capacity of the heart decreases.  In the long term, this leads to an overload of the heart and thus to heart failure.

What are the Risk Factors for Heart Failure?

Although the risk factors associated with heart diseases in dogs vary depending on the dog, it is important to know and understand them to better monitor your four-legged friend's cardiovascular health. Age often plays a role, as older dogs are more susceptible to heart problems. Furthermore, certain breeds are predisposed to specific heart problems, which underscores the importance of knowing your dog's genetic predisposition.

Dilated cardiomyopathy occurs particularly frequently in large breeds such as Doberman, Boxer, Great Dane, St. Bernard, German Shepherd, and Cane Corso, but smaller breeds like Cocker Spaniels or Portuguese Water Dogs can also be affected. It primarily occurs in adult dogs aged 5 to 10 years, but there are also juvenile forms that appear as early as 1 to 2 years of age. Males are more frequently affected and usually suffer more severely. There are primary causes, which include hereditary genetic changes in the heart muscle, as well as secondary causes, which can include viruses, inflammations, or toxic influences.

Mitral valve insufficiency is a common disease, especially in small breed dogs such as Chihuahuas, Poodles, Dachshunds, or Yorkshire Terriers. In Cavalier King Charles Spaniels, it is particularly common and often occurs at a young age, whereas in dogs of other breeds, it is usually diagnosed only from the age of 6 years. Overweight can increase the risk of mitral valve insufficiency, as it puts additional strain on the heart. Furthermore, certain underlying diseases, such as hypothyroidism, can contribute to the development of heart problems in dogs.

A balanced, nutrient-rich, and high-quality diet is crucial for dogs' heart health, as nutrient deficiencies (Mangel) such as taurine, carnitine, vitamin E, and omega-3 fatty acids can be linked to heart problems.

What are the Signs and Symptoms of Heart Disease in Dogs?

The symptoms of heart disease in dogs vary greatly depending on the stage of the illness and the underlying condition. The first signs are often subtle and not easy to recognize. Sometimes, the disease remains unnoticed for years and causes no discomfort. For example, a heart murmur is often discovered by chance during a routine visit to the vet. It is therefore difficult to diagnose heart disease based on external signs alone, and an accurate diagnosis always requires an examination by a veterinarian.

The most common signs of heart disease include:

• Coughing, especially after exertion or at rest
• More or less pronounced fatigue
• Intolerance to exertion and heat
• Faster breathing, leading to shortness of breath
• Loss of appetite
• Weight loss
• Weakness or sudden collapse

If your dog shows any of these signs, you should consult your veterinarian. They will carefully examine the heart and the entire respiratory system and recommend further tests to make a diagnosis. Early detection allows for earlier treatment of the disease, which can improve your dog's prognosis and quality of life.

Treatment and Care for Dogs with Heart Disease

The medicinal treatment of heart diseases in dogs is highly individual and depends on the specific type of heart damage. Therefore, a precise diagnosis, usually made by a veterinary cardiologist, is essential. Treatment may include administering medications to improve heart function, lower blood pressure, and reduce fluid accumulation in the body. It is important that medications are given regularly and exactly according to the veterinarian's instructions.

Some dogs also benefit from a tailored diet aimed at maintaining optimal weight, reducing strain on the heart, and protecting the heart muscle.

It is equally important to adapt the dog's environment to its needs by ensuring a calm and stress-free atmosphere, avoiding overexertion, while also allowing for moderate physical activities. Especially in summer, it is crucial to avoid heat by offering the dog cool and shady spots, ensuring it always has access to fresh water, and taking walks only in the early morning or late evening hours.

When treating heart diseases in dogs, the focus is usually on improving the quality of life rather than a complete cure. Open communication with your veterinarian, regular check-ups, careful monitoring of medication intake, and attentive observation of your dog contribute to providing your heart-diseased dog with the best possible comfort of life.