CONGENITAL HEART DEFECTS
By Larry Tilley, D.V.M.
What is a congenital heart defect or congenital heart disease?
The word “congenital” means inborn or existing at birth. The terms congenital heart defect and congenital heart disease are often used to mean the same thing, but the word “defect” is more accurate. The heart ailment is a defect or abnormality, not a disease. A defect results when the heart or blood vessels near the heart do not develop normally before birth.
How do congenital heart defects develop?
Congenital heart defects are rather uncommon. In most cases, we do not know what causes them. Heredity sometimes plays a role in congenital heart disease. More than one puppy or kitten in a litter may have a congenital heart defect, but this rarely occurs. Other factors that affect the heart’s development are presently being studied. The truth is that we still don’t know what causes most congenital heart defects.
How do we confirm that your pet has a congenital heart defect?
The first action that a veterinary cardiologist usually takes is to give a physical exam. The doctor also may want an x-ray, electrocardiogram (EKG or ECG), echocardiography, or blood test. The EKG is recorded from a machine that receives tiny electrical impulses from the beating heart and records them in a zig-zag pattern on a moving strip of paper. This graph of the heart is called an electrocardiogram. The chest x-ray gives the cardiologist information about your pet’s lungs and the heart size and shape. An echocardiogram uses high frequency sound waves to create an image of the heart’s internal parts. A Doppler test uses sound waves to measure blood flow. By combining these studies, the doctor learns about the heart structure and work.
How do we treat congenital defects?
Most animals with heart and blood vessel defects do not need surgery. Many medical treatments are available to help the heart work properly. With congestive heart failure, the heart is not able to pump blood well enough for the body to get the nourishment it needs for normal work and activity. When the heart cannot work as it should, fluid can build up in the lungs, causing labored breathing. Fluid also may build up in the rest of the body, causing swelling. Animals with congestive heart failure usually become easily tired, have rapid or labored breathing, build up fluid, or have more than one of these symptoms. Diuretics are used to help get rid of the extra fluid. Other medical treatment usually includes digoxin and vasodilators that can cause the heart to contract with more force. If your animal needs heart surgery, the operation is usually done in the same hospital where the diagnostic tests were done or in some situations the animal is referred to a veterinary school. The goal of surgery is to repair the defect as completely as possible and make the circulation as normal as it can be.
Dr. Larry Tilley is a veterinarian and the owner of VetMed, a veterinary specialty consulting service based in Santa Fe.
This article first appeared in the Spring/Summer 1997 issue.
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