Health Matters
Heart Health Going to the Dogs

by Lori Drourr, DVM

Many pet owners are surprised to find out that, just like humans, pets can have heart disease. In fact, the American Veterinary Medical Association estimates that approximately 3.2 million of the dogs examined annually by veterinarians in the United States have some form of acquired heart disease. Read on to find out what you need to know about your dog’s heart.

Canine Heart Disease: The Basics

Heart disease in dogs often is classified into two broad categories: congenital and acquired. Let’s take a quick look at the two.
Congenital heart defects are present at birth. Puppies can be born with small or large defects (holes) in their heart walls or malformation of their heart valves. The most common congenital defect is failure of a blood vessel called the ductus to close at birth, which results in abnormal blood flow. Your veterinarian can hear this abnormal blood flow (a heart murmur) during routine physical examination. Although this defect, if left untreated, can result in heart failure, there are surgical and non-surgical procedures that can resolve this defect, allowing your new puppy to live a normal, heart-healthy life. These types of defects usually are diagnosed when the dog is very young; they are relatively rare compared with the second category: acquired heart defects.
Acquired heart defects are absent at birth; they can occur due to genetic or environmental factors and develop at some point in the pet’s lifetime. Chronic degenerative valve disease is the most common heart disease in dogs. It typically affects small to medium older dogs. Degeneration or thickening of the heart’s mitral and/or tricuspid valves results in a valvular leak allowing some blood to flow backward instead of forward to the rest of the body. A less common type of acquired heart disease, cardiomyopathy, affects the ability of the heart muscle to contract or pump blood. Cardiomyopathies typically occur in large breed dogs, with Doberman Pinschers and Boxers having a likely genetic basis for this acquired disease.  

Diagnosing and Treating Canine Heart Disease

When it comes to heart disease and your pet, regular visits to your veterinarian can make all the difference. During an examination, a veterinarian may detect signs pointing to heart disease, such as an irregular heart rhythm or a heart murmur. Early detection is key to learning about long-term prognosis and management. If your dog is a breed that is more likely to have heart problems, your veterinarian may refer you to a veterinary cardiologist for breed screening at an early age.
If heart disease is suspected, your veterinarian will want to learn about the symptoms and behaviors you’ve seen at home, and he or she will perform a thorough physical examination. There are a number of diagnostic tools your veterinarian can use to confirm whether a heart condition is present, including x-rays, an electrocardiogram (ECG), blood pressure monitoring, and even blood tests. X-rays of the chest are used to look at the relative heart size and evaluate the lungs. An ECG looks at the electrical activity of the heart. If electrical rhythm disturbances are noted or suspected, you may be referred to a veterinary cardiologist for a holter monitor. A holter monitor (worn by the patient while he or she is at home) allows for the 24-hour evaluation of the electrical activity of your pet’s heart. Results are evaluated to determine if arrhythmias (abnormal electrical beats) are the cause of symptoms, such as exercise intolerance or collapsing episodes, and to determine if anti-arrhythmic medication would be beneficial for your pet.  
Echocardiography (heart ultrasound) remains the gold standard for evaluating cardiac structure and function. Your veterinarian will likely refer you to a veterinary cardiologist who has extensive training in echocardiography.
If your pet is diagnosed with heart disease, your veterinarian can work with a veterinary cardiologist to ensure your companion continues to enjoy a good quality of life. Just as some people have heart disease that does not impact their quality or quantity of life, some animals can continue to live a long and healthy life despite certain underlying heart diseases. As with most medical conditions, new treatments for heart disease are always becoming available. Depending on the specific case, heart disease may be successfully managed with early detection and treatment.  
Similar to human heart patients, there are many medications available for companion animals with failing hearts. Medications include drugs to decrease the workload of the heart, to strengthen the heart’s contractions, to minimize arrhythmias, and to eliminate breathing difficulties or coughing. Surgery or cardiac catheterization procedures have improved the long-term prognosis of many congenital defects in animals. New medications have been approved for use in dogs that have been shown to improve the quality and quantity of their lives with acquired cardiac diseases. Your veterinary cardiologist will individualize a treatment plan that fits best with your pets’ needs.

Keeping Your Pup Heart-Healthy

A balanced diet, regular exercise and regular veterinary care are important for the overall health of your canine friend. It’s rare for dogs to acquire heart disease secondary to high cholesterol (such as seen in humans). However, maintaining a balanced diet for weight control is part of a healthy lifestyle – and beneficial for reducing the workload on the heart of a patient with heart disease. Additionally, low thyroid levels, anemia and high blood pressure can significantly affect the heart’s function. Annual check-ups with your canine companion’s veterinarian are the most important step in assessing heart health.
With veterinary care, canine companions with heart disease can lead happy, good-quality lives and continue to warm our hearts every day.

About the Author
Lori Drourr, DVM, a graduate of the University of Florida College of Veterinary Medicine, completed her cardiology residency training at Texas A&M University. She sees patients at San Francisco Veterinary Specialists on Mondays and Tuesdays. See www.sfvs.net for more information.