SlimDoggy Health Check: Cardiovascular and Circulatory Disease
We continue our SlimDoggy Health Check series, moving on to the Cardiovascular and Circulatory systems of the dog.
As in humans, the heart is the most critical organ in your dog’s body. It is responsible for pumping blood throughout their body and carrying life-giving oxygen and nutrients along with it to the other organs and tissues. The cardiovascular (or circulatory) system is made up of the heart, arteries, veins and capillaries or the blood vessels. A dog’s heart is comprised of four chambers (right-left ventricles and right-left atrium). A normal heartbeat for a dog is between 60 -120 beats per minute.
The arteries are blood vessels that carry oxygen-rich blood throughout the body to all of the dog’s organs and tissue. Veins are much thinner blood vessels and they carry blood from the other parts of the body back to the heart to re-oxygenate. It all works much the same way as it works in humans.
There are several serious heart diseases that may befall your pet. One of them, Heartworm, we covered in an earlier series, Part 1 and Part 2.
Other heart conditions include:
- Chronic valvular disease
- Dilated Cardiomyopathy
- Infective endocarditis
Chronic valvular disease: This is a common disease that affects the valves of the heart. It is usually found in breeds such as Cavalier King Charles Spaniels, Toy Poodles, Cocker Spaniels and other small breeds. It is a degenerative disease that affects the proper functioning of the valves within the heart. The valves control the flow of blood through the chambers of the heart. In the course of the disease the valves begin to thicken and do not open and close fully or correctly. When they begin to fail in this way, blood regurgitates back into the left atrium causing it to enlarge. The inefficiencies caused by the malfunctioning valves put extra stress and strain on the heart, reduces cardiac output and may eventually lead to cardiac arrest and pulmonary edema (fluid in the lungs). Symptoms of the disease may include lethargy, a cough after exercise and even fainting spells. Diagnosis is straightforward as a pronounced heart murmur is likely to be heard. An EKG and xrays may also help pinpoint the progression and exact location, as well as to rule out Heartworm. At our last vet visit, a heart murmur was detected in Maggie, so we will be keeping a close eye on her. When Chronic Valvular Disease is diagnosed, it is ‘staged’ identifying the severity. This in turn defines the treatment. Diuretics to help clear excess fluid may be diagnosed as well as other medications to help the heart pump more efficiently. Diet and exercise are also important in treatment as well as prevention.
Dilated Cardiomyopathy (DCM): DCM is a disease that causes the heart to enlarge and leads to a weakening of the heart muscle and its ability to pump blood effectively throughout the body. The disease typically affects large breed dogs including Doberman Pinschers, Irish Wolfhounds, Scottish Deerhounds, Boxers, Great Danes, Dalmatians and Newfoundlands. There is no known cause, although nutritional, infectious and genetic components are suspected. Symptoms may be dependent upon the affected chambers of the heart. They may include lethargy, weakness, weight loss or collapse due to decreased delivery of oxygenated blood to the body or coughing, increased respiratory rate or abdominal distention due to congestion of blood in the lungs. Diagnosis is typically made through history, abnormal heart sounds, blood tests and possibly xrays and an EKG. Treatment is focused on improving the functioning of the heart. Diuretics to reduce fluid build-up and Vasodilators that dilute the blood to allow more efficient flow may be prescribed by your vet. A dog with DCM will need monitoring and regular veterinary care.
Infective endocarditis: Endocarditis is an infection and inflammation of the inner lining of the heart. It is more commonly found in large breed male dogs ages four to six. It is usually caused by a bacterial infection that settles in the heart. The infection leads to thickening of the valves in the heart which reduces the efficiency and performance of the heart. These changes to the heart are irreversible. This is a serious disease which, left untreated, could lead to death. Symptoms include: fever, cough, lethargy & weakness, refusal to eat, difficulty breathing, pain and GI disturbances. Diagnosis is made with a thorough history, blood and urinalysis tests and EKG. Treating Endocarditis includes antibiotics to eliminate the infection, but this will not repair heart tissue already damaged. Prevention is critical, especially in dogs already diagnosed with a heart murmur or other similar condition. Regular veterinarian care and follow-up will be required.
Note: SlimDoggy is not providing veterinarian advice in this series, we are only describing various health issues. If you suspect your dog is sick, see your vet for professional medical care.
Cardiovascular System of the Dog
Cardiac Arrest in Dogs
Structure and Function of the Cardiovascular System in Dogs
Heart Disease in Dogs: Chronic Valvular Disease and Dilated Cardiomyopathy
Dilated Cardiomyopathy (DCM)
Endocarditis in Dogs