Causes of Heart Failure in Dogs
Heart failure, also known as congestive heart failure, is the end result of a progressively weakened heart muscle and almost always is ultimately fatal. Heart failure can be caused by a number of different things, including injury or trauma to the heart, congenital or developmental defects of the heart chambers or valves, bacterial, viral or fungal infections, ingestion of toxins, environmental stressors, breed predispositions and hereditary heart abnormalities. Heart failure occurs in dogs of both genders and of all ages and breeds, including mixed breeds. It is more common in middle-aged and older animals. Toy dogs and small breeds usually develop heart failure as a result of chronic valvular disease that is accompanied by regurgitation of blood through the mitral and/or tricuspid heart valves. The hearts of large and giant-breed dogs more frequently fail from a disorder known as dilated cardiomyopathy, or DCM, which involves abnormal enlargement of the heart.
The heart of a dog in heart failure is weak and can’t pump blood properly. This causes an abnormally large amount of blood to stay in the dog’s arteries, which carry oxygenated blood from the heart throughout the body; and veins, which return unoxygenated blood from the body back to the heart and lungs. This interferes with the mechanisms that normally regulate fluid balance and causes fluid to accumulate in the chest, creating congestion. Sometimes, the congestion associated with heart failure only causes mild discomfort with few noticeable signs. Unfortunately, in many cases, heart failure leads to life-threatening fluid overload and total heart shut-down. Regardless of the inciting cause, when a dog’s heart cannot fill with and pump blood properly, the health of other organs, including the liver, lungs, kidneys and brain, becomes compromised.
Prevention of Heart Failure
Unfortunately, there are not a lot of reliable things that can be done to reduce the risk of heart failure in companion animals. One important thing that responsible owners can do to stave off heart disease is to prevent their dogs from becoming obese. Overweight dogs, like overweight people, are predisposed to developing heart problems. Dogs that are fed a high-quality, palatable, nutritious diet and exercise regularly tend to have better heart health than portly, sedentary animals. All dogs should have free access to fresh water, safe housing, soft bedding and appropriate protection from weather extremes at all times. Heartworm infection can contribute to congestive heart failure, and dogs living in areas where heartworm is prevalent should be kept on a regular course of heartworm preventatives as directed by their veterinarian.
A number of medications are available to treat or at least manage the effects of heart failure in dogs. Drug therapy can help reduce the build-up of fluid in the dog’s chest, ease the heart’s workload and relieve the breathing difficulties that invariably accompany heart failure. Of course, the dog’s veterinarian is in the best position to advise owners about appropriate treatment options.