Heart Disease in Dogs and Cats
first thing that wears out. Like all mammals, dogs and cats have a four-chambered heart, consisting of a left and right upper chambered atrium and a left and right lower chambered ventricle. The left and right atria receive blood from the body and lungs respectively. The left ventricle is responsible for pumping oxygen-rich blood from the lungs out through the pulmonary artery to the lungs for oxygen.
The heart has 4 one-way valves to keep blood flowing in the right direction. The valve between the left atrium and ventricle is the mitral valve. The one between the right atrium and ventricle is the tricuspid valve. The one regulating blood going into the aorta is the aortic valveand the one regulating blood going to the lungs is thepulmonic valve. The mitral valve is the most fragile valve in your pet’s heart. In dogs, it is often the first one to wear out.
- Coughing is one of the 1st noticeable signs. This is because an enlarged, failing heart allows fluid to back up into the lungs and also press on the windpipe (Cats are more likely to make asthmatic-like sounds than to cough).
- Rapid breathing
- Poor appetite
- An enlarged tummy
- Pale or bluish gums
- Rapid, weak pulse
Please report these or any other unusual changes to your veterinarian immediately. If he suspects a heart problem, the first step would traditionally be to do an x-ray. If the x-ray shows an enlarged heart, your vet may be satisfied with that and begin treatment.
Effects of a Failing Heart:
In dogs, the valves are often the heart structures that are affected. Hearts disease in cats usually involves the entire heart muscle and not just the valves. While dogs let us know early on that there is a problem, we are often unaware that cats have a problem until the heart is well on the way to failing. Often the only signs in your cat are weight loss and difficulty breathing. In all cases of heart disease in dogs and cats, as the circulatory system fails, the kidneys, liver and all other organs are flooded with stagnant blood and work inefficiently because they don’t get the blood they need.
Cats with this form of heart disease don’t survive long. Signs of all forms of heart disease in cats are similar, so your vet may need several tests to make a diagnosis.
Congestive Heart Failure (CHF):
CHF is an enlarged heart that occurs when the heart is unable to meet the circulatory demands of the body. No matter what the underlying heart problem is, CHF is usually the end result. As this disease progresses, the normal triangular shape of the heart becomes rounded. This is very noticeable on an x-ray and will make a diagnosis easier.
- Medication – There are several medications available to treat CHF; medication(s) will be prescribed by your veterinarian depending on the underlying cause.
- Food – Foods rich in Omega-3 Fatty Acids, L-Carnitine and Taurine, such as Hills™ H/D and KD, have been shown to help pets suffering from CHF.
- Other things to do – Keeping your pet’s weight optimal is a key factor in helping them with CHF. While exercising your pet, keep activity to a level short of what it would take to cause them to breathe heavily, pant, or elevate their heart rate. Dogs and cats can benefit physically and mentally from activity.
Valvular Disease of Dogs and Cats:
This is the most common form of heart disease in dogs and the rarest in cats. 60% of dogs over 8 years old have some degree of this problem. Less than half of these dogs show noticeable symptoms. Age-related scarring of the mitral valve is quite common in all older dogs. Many veterinarians have noticed that small breeds of dogs that eat soft food and table scraps eventually develop chronic mouth infections and periodontal disease. It is very common for these pets to also have a heart murmur related to their mitral valve.We think that bacteria move from the infected gums through the blood and attach to the heart valves to cause a condition called endocarditis that eventually scars the heart valves.
These are less common heart problems that affect both dogs and cats. For these your veterinarian may refer you to a pet cardiac specialist for testing.