Heart disease in dogs and cats is caused by either a genetic predisposition or a physical trigger, such as enzyme deficiencies or hyperthyroidism. Genetic heart disease is called congenital and non-genetic heart disease is called acquired heart disease.
There are some breeds of dog that are very prone to heart disease, such as Newfoundlands, Dobermans, and Great Danes. Some breeds, such as the Cavalier King Charles Spaniel, are genetically likely to develop a heart murmur, which leads to heart disease.
Causes of Congenital Heart Disease
- Patent Ductus Arteriosis - Dogs Dogs are often diagnosed with patent ductus arteriosus (PDA) which occurs when the connecting blood vessel between the aorta and the pulmonary artery does not close properly after birth.
- Aortic Stenosis - Dogs Large breed dogs are the most likely candidates for aortic stenosis, which is a narrow or partially blocked aorta.
- Pulmonic Stenosis – Dogs Some dogs suffer from heart disease caused by pulmonic stenosis, which is a narrowing of the pulmonary artery. This artery carries blood to the lungs to be oxygenated, so this form of heart disease forces the heart to work harder to pump blood to the lungs.
- Ventricular or Atrial Septal Defect – Dogs and Cats Your dog or cat’s heart (and yours) is separated into areas called ventricles and atria. A ventricular septal defect is a hole in the heart wall between the right and left ventricle of the heart, while an atrial septal defect is a hole between the left and right atria.
- Persistent Right Aortic Arch - Dogs When puppies are born, they have an aortic arch which is supposed to deteriorate after birth, but if that arch does not go away, it can become wrapped around the esophagus.
- Dysplasia – Cats Dysplasia is a malformation of the heart valves.
Causes of Acquired Heart Disease
- Dietary Deficiency – Dogs and Cats Dogs and cats need a healthy balanced diet to keep their heart strong and efficient. If they do not get enough of the enzymes taurine and L-carnitine, the strength of the heart may diminish, resulting in cardiomyopathy (an enlarged heart) and heart disease. It is important to investigate your choice of pet food, because if it is not providing your pet with enough taurine and carnitine, a supplement should be given.
- Pericardial Disease – Dogs The pericardium is the sac that surrounds the heart, and when diseased, it can restrict the heart and prevent consistent strong heart beats.
- Heartworm Infection – Dogs and Cats If a dog or cat becomes infected with heartworm, and it goes untreated, it can lead to heart disease.
- Endocardiosis - Dogs The most common form of heart disease in dogs is a valvular problem called endocardiosis, while in cats it is the least common. Endiocardiosis is usually found in older dogs, because the valve has been working for so long it now fails to close and open all the way. This causes the valve to become leaky, and allows some blood to leak back into the atrium or ventricle from which it came. This form of leak can do a lot of damage after a while. The heart becomes enlarged and can push up against the windpipe, causing a cough. The overflow of blood can also get pushed into the lungs. These leaky valves are also called heart murmurs, which are rated on a scale from one to six, with six being the most damaging.
- Hypertrophic Cardiomyopathy – Cats When something happens that causes the heart to struggle to do its job, the heart can become enlarged, which is called cardiomyopathy. Hypertrophic cardiomyopathy occurs when the heart muscle thickens, resulting in abnormal heart function.
- Dilated Cardiomyopathy - Dogs Dilated cardiomyopathy is a result of a taurine deficiency in the diet. This is no longer as common is it used to be due to increased taurine in most cat foods available today.
- Restrictive Cardiomyopathy - Cats Restrictive cardiomyopathy results in stiffness in the ventricles of the heart, with a currently unknown cause.
- Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) - Dogs and Cats Arrhythmogenic right ventricular cardiomyopathy is an arrhythmia, or an irregular heartbeat, in the right side of the heart.
- Hyperthyroidism – Cats Hyperthyroidism causes the blood to have a high level of hormones, which is very hard on the heart, resulting in heart disease. It's often the cause of hypertrophic cardiomyopathy in cats.
The symptoms and treatments for heart disease may vary based on what’s causing the disease in your pet.
This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.