Understanding cardiac disease in dogs

Cardiac disease can afflict dogs of all breeds and sizes. Find out what the signs are, and how these conditions can be diagnosed and treated using an integrative approach.

George is a nine-year-old poodle. During a routine checkup six months ago, his veterinarian heard a heart murmur. More recently, his family noticed he was “not his normal spunky self”, and was panting and restless. Radiographs of George’s chest showed a large heart and fluid in his lungs. An echocardiogram revealed a leaky mitral valve. The diagnosis was congestive cardiac disease. George was given emergency treatment with a diuretic to reduce the fluid in his lungs. His family was presented with several long term treatment options, including drugs, herbs and nutritional therapy. Because George was in heart failure, his people opted to take an integrative approach and use every possible treatment, both conventional and alternative. So he was started on an ACE inhibitor along with Hawthorne extract and a Chinese herbal formula called Wu Ling San. His family also started adding vegetables to his diet.

Whether you have a Chihuahua or a Great Dane, your dog is at risk of developing cardiac disease at some point in his life. Unlike humans, dogs rarely have heart attacks or develop heart problems from a buildup of cholesterol in their blood vessels. Most canine cardiac disease arises from normal wear and tear on the heart structures. types of canine heart disease There are two main categories of cardiac disease – congenital and acquired. Congenital heart diseases are problems a dog is born with, such as a hole in the wall between heart chambers (known as a ventricular septal defect). These diseases are rare and tend to be very severe, limiting the dog’s lifespan. Acquired heart diseases are more common and develop over time. They are frequently associated with aging or physical injury to the heart from trauma (such as getting hit by a car) or certain infections (like heartworm disease).

The location of the problem and the specific tissues involved determines the type of acquired cardiac disease.
• Valvular disease occurs when the valves between heart chambers leak. This leads to abnormal bloodflow in the heart and can result in hypertension and fluid collection outside the blood vessels, commonly in the lungs and belly. The most frequently involved valve is the mitral valve. Older small breed dogs, such as Chihuahuas, miniature and toy poodles, Pomeranians and miniature Schnauzers, are predisposed to this condition.
• Myocardial disease involves the heart muscle. It can occur if the heart muscle becomes too thick (hypertrophic), too thin and stretched (dilated), or has been damaged from injury or infection.
• An arrhythmia is a general term describing abnormal electrical signals in the heart that cause individual cells in the muscle tissue to contract at different times or at an incorrect rate. This can lead to a heartbeat that’s too fast or too slow, or to a lack of coordination between the different parts of the heart. In any of these situations, the muscle is unable to pump blood effectively.

Signs of a heart problem

The symptoms of cardiac disease in dogs depend on the type of disease and its location in the heart. In general, the signs include:

• Weight loss
• Decreased appetite
• Weakness (gets tired easily when playing or with mild exercise)
• Coughing
• Breathing heavily
• Swelling in limbs (edema)
• Bloated abdomen

The most common reason for a trip to the veterinarian is coughing. It can be a soft, quiet cough that occurs at night or when the dog is lying down, or a loud, hacking cough that occurs randomly. Dogs with arrhythmias can have no signs of disease other than “fainting” episodes. The dog is completely normal, then suddenly collapses for several seconds to minutes. Unlike a seizure, the dog does not twitch or recover completely within minutes of an episode.

Diagnostic tools and techniques

Diagnosis always begins with a thorough examination. The veterinarian will ask about any abnormalities you’ve noticed and check the dog for any telltale signs of heart disease. These may include any of the above signs along with a heart murmur (abnormal heartbeat sound), abnormal sounds in the lungs, weak pulse strength or lack of regularity, and signs of fluid collection in the legs or belly. The next step is imaging. Chest radiographs look at all the organs in the chest, including the heart and lungs. Changes in the shape or size of the heart, and fluid in the lungs (pulmonary edema) can both readily be seen. An echocardiogram is an ultrasound of the heart that provides more detailed information about the thickness and function of the heart muscle. It can also show abnormal bloodflow through valves and find small
abnormalities not visible in radiographs. Further testing may involve electrocardiography, which measures electrical activity in the heart. This is important for diagnosing arrhythmias.

The NT pro-BNP is a blood test that measures the level of a protein released when the heart muscle is stretched beyond normal capacity. This test can be useful when it’snot certain whether symptoms are related to the heart or lungs. While it is a useful screening tool, its results cannot be used to make a definitive diagnosis of cardiac disease.

Treatment options

Conventional options include drug therapy and procedures to manage fluid accumulations. Drug therapy is aimed at managing symptoms, such as slowing the heart rate, as well as helping the heart function more effectively. Different types of medication (ACE inhibitors, betablockers, anti-arrhythmic drugs, diuretics) are chosen depending on which type of heart disease is present. Alternative therapies can be effective on their own or used in combination with conventional treatments. Just remember that when herbs are combined with some cardiac drugs, unwanted side effects or contraindications might occur. Always discuss any herbs or other supplements with an integrative veterinarian before giving them to your dog, especially if he’s already on heart medication.
• Chinese herbal formulas can be very helpful for treating cardiac disease as well as other problems that may accompany it. Xue Fu Zhu Yu Tang is traditionally used for blood deficiency and stagnation. Wu Ling San has diuretic properties, so can help resolve fluid accumulations.
• Western herbs can also be effective:
• Hawthorne (Crataegus oxyacantha) increases heart muscle contractility and reduces the resistance of bloodflow in small vessels. It may, however, enhance the effects of digitalis, so these two treatments should not be combined.
• Ginkgo (Ginkgo biloba) relaxes blood vessels to enhance circulation.
• Salvia miltiorrhiza increases bloodflow to the vessels of the heart.
• Dandelion (Taraxacum officinalis) is another effective diuretic that helps resolve fluid accumulations.
• Nutritional therapy is important. The omega 3 fatty acids in fish oil reduce the potential for arrhythmias and are anti-inflammatory. Carnitine improves metabolism in heart muscle cells. The combination of selenium and vitamin E scavenges free radicals that promote heart muscle cell injury. Supplementation with these nutrients will help decrease further injury to muscle cells and, hopefully,
slow disease progression. For more information on alternative treatments for cardiac disease, check out The Manual of Natural Veterinary Medicine by Drs. Susan Wynn and Steve Marsden.

Can cardiac disease be prevented?

While there is no specific research on how to prevent heart disease in dogs, there is some evidence that reducing inflammation can improve heart function. The best recommendation is to give your dog a lifestyle that does not encourage inflammation in the body. Do not allow him to get overweight and give him plenty of exercise. Good dental hygiene and a diet rich in antioxidants will also help keep systemic inflammation to a minimum, so brush your dog’s teeth and feed him plenty of fruits and vegetables.

Cardiac disease can be scary, but with the right combination of treatments it can be managed. Ginkgo (Ginkgo biloba) relaxes blood vessels to enhance circulation.