Heart Disease and Treatment in Your Dog and Cat
Friday, October 01, 2004
Joshua Gidlewski, DVM
Diplomate ACVIM (Cardiology)
Garden State Veterinary Specialists
You may know that heart disease is the leading cause of death for men and women in the United States. But did you know that heart disease also occurs commonly in pets all across our country? Heart disease affects an estimated one in every ten dogs and cats. Our pets can be born with heart disease, which is called congenital cardiac disease, or they can be born with normal hearts and then develop heart disease later on in life, this is call acquired cardiac disease.
Acquired cardiac disease is more common in dogs and cats than congenital cardiac disease. In dogs the two most common types of acquired heart disease are chronic valvular disease (CVD) and dilated cardiomyopathy (DCM). CVD is a slowly progressive degeneration of the valves in the heart. Although it can occur in any breed at almost any age, it occurs most commonly in middle aged to older small breed dogs and is slightly more common in males than females. Some breeds predisposed to the development of CVD include the Cavalier King Charles Spaniel, Chihuahua, Miniature/Toy Poodle, Daschund and Maltese among others. DCM is the second most common acquired cardiac disease in dogs. It is a condition where the heart dilates, the walls become thinner and the heart dramatically weakens. DCM is most common in middle aged to older large breed male dogs. Doberman Pinchers, Irish Wolfhounds and Great Danes are among the more commonly affected breeds.
The most common type of acquired cardiac disease in the cat is hypertrophic cardiomyopathy (HCM). In contrast to DCM, HCM is characterized by a very thick heart that is strong and contracts well, but is stiff and does not relax well. Maine Coons, American Shorthairs and Persians are particularly predisposed to HCM.
Congenital heart disease in both dogs and cats is a result of malformations of the heart which occur when the heart is developing in the fetus. The possible types of congenital heart disease are nearly endless, but the most common congenital defects are patent ductus arteriosus (PDA), sub-aortic stenosis (SAS), pulmonic stenosis (PS) and ventricular septal defects (VSD). PDA and VSD are inappropriate and abnormal communications between different chambers of the heart, while SAS and PS are two abnormal obstructions to blood flow throughout the heart.
Because our pets cannot talk to us, it is often difficult to appreciate the clinical consequences associated with heart disease. In fact, it is often not until the disease is severe that owners are able to recognize that their pet has a problem. The most common signs that owners recognize in patients with heart disease include difficulty breathing, coughing, exercise intolerance and intermittent weakness or collapse. These symptoms that owners often recognize are typically come on suddenly and are progressive. These pets will often continue deteriorate over the next several hours and days unless a veterinarian is given the chance to intervene and alter the course of the disease.
Fortunately, there are often abnormalities on the physical exam that may cause your primary veterinarian to suspect that heart disease is present in your pet and by utilizing different diagnostic tests, some basic and some advanced, a complete understanding of the heart disease that is present can be achieved. Diagnostic tests which often prove helpful in defining the exact type and extent of the heart disease present in your dog and cat include: electrocardiogram – which record short periods of electrical activity in the heart; chest radiograph (X-ray) – which reveal the information about the size and shape of the heart as well as giving us information about the health status of the lungs; Holter monitor/event recorder – which record long periods, usually 24 hours to several days, of electrical activity in the heart; echocardiogram – which is an ultrasound of the heart which provides vital information about the structure and function of the heart, angiocardiography – which can provide additional information about the structure and function of the heart and even occasionally an MRI can be give us beneficial information about the heart and it’s surrounding structures.
Once heart disease has been identified and the extent fully defined a decision must be made about whether medical or surgical intervention will help to improve the quality and duration of your pet’s life. Fortunately veterinary medicine is continuing to make progress in the recognition and treatment of heart disease. Many conditions such as congestive heart failure, which would result in a rapid untimely death if not treated, can now be treated with medications that prolong your pet’s life and return them to a near normal quality of life. Other conditions, such as life threatening heart block (which causes a dangerously slow heart rate) can be controlled by implanting a pacemaker. Still other diseases, such as PDA and PS can be treated by using cardiac catheterizations to give a puppy with a severe congenital defect a normal life expectancy and quality of life.
Most owners would shudder at the thought of their beloved four-legged companion being diagnosed with heart disease but, over the past 20 years there have been remarkable advances in the field of veterinary cardiology that permit earlier, more reliable, detection and intervention with animals suffering from heart disease. With each passing year primary veterinarians working in conjunction with board certified cardiologists are helping more and more pets to live, and live well, with heart disease. Veterinarians and owners are mending one heart at a time………
This article is for informational purposes only and should not be used as a substitute for the professional advice of your veterinarian.
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