Valvular Heart Disease in Canines

The heart is the organ responsible for circulating oxygen rich blood through our dog’s bodies. It can be thought of as a pump. Congestive Heart Failure can be defined as when the circulatory demands of the body can no longer be maintained by the heart. It is not a disease per se, more like a “state of being”. However, CHF is caused by an underlying disease state. Fortunately, many of these cardiac diseases can be controlled with medication for at least some period of time. In the following article, I will discuss mitral and tricuspid valve disease in dogs that result in Congestive Heart Failure as well as the available treatment options available.

The most common heart disease in small dogs is valvular disease. Specifically, mitral and tricuspid valve disease. These are two small valves that separate the chambers of your dog’s heart. Dog’s have 4 chambered hearts with 2 atrium and 2 ventricles. These are separated on the left and ride side of the heart by the mitral and tricuspid valves. Damage or defects to these valves will cause blood to no longer flow smoothly and instead turbulently hit the side of the heart wall. This results in an abnormal sound referred to as a heart murmur. Over time, this results in damage to the heart, inflammation and cardiac enlargement. As the heart gets bigger, it becomes more difficult to contract fully.

When the heart can no longer push enough blood through the body circulatory demand is compromised and blood will start to back up into the organs where it last came from. In right-sided heart failure, blood will return to the liver and in left sided, the lungs. As a result, congestive heart failure will cause coughing, exercise intolerance, and fatigue.

If your Veterinarian suspects your dog is in congestive heart failure from valvular disease, they will recommend radiographs and blood work. These tests may show where the blood is backing up and assist with selecting the correct medications and dosage to improve cardiac function. Fortunately, in many cases of mitral and tricuspid valve disease, medications can be used to help your dog’s heart obtain a better contraction as well as remove excess fluid from your dog’s body. Today, three medications are commonly used, Enalapril, Lasix, and Pimobendan.

Since congestive heart failure is a state of being, these medications can improve heart function enough to return your dog to full function and without any clinical symptoms for at least some period of time. Dogs can go in and out of congestive heart failure depending on the medications, doses, and progression of underlying disease.

Veterinary Cardiologists are specialists that have extensive training and advanced equipment to help in the diagnoses and treatment of heart disease. In some cases your veterinarian may recommend a cardiology consult for an echocardiograph. An echocardiograph is an ultrasound machine specially designed to evaluate heart function. Using and echocardiograph a cardiologist can take measurements of your dog’s heart and the blood flowing through the heart. This can be used to help diagnose and stage the level of heart disease in your dog. Using this information, a customized treatment plan using additional medications or altered dosing may be recommended.

If you suspect your dog has valvular disease, it is recommended to schedule and appointment with our Veterinary Hospital for evaluation.

Jeffrey Stupine, V.M.D.