If a dog's heart rate is very rapid and they haven't just finished a long run or play session, it could be just one of the symptoms of a potential heart problem. Heart disease in dogs is not hard to diagnose but they may not get diagnosed until the condition is more advanced if pet owners don't get annual physical exams on dogs under the age of 7 and twice a year exams starting at age 7.
Be sure to get your dog regular checkups with a DVM (veterinarian) to monitor their heart health and watch for some common signs of heart disease so you can explore treatment options for your dog as soon as possible if necessary.
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Difficulty breathing and coughing in dogs
One potential symptom of a heart problem is if the dog's heart is beating fast and they're panting when they haven't been exercising. The panting may indicate that they're experiencing difficulty breathing.
When heart problems are more advanced, your dog may have more difficulty breathing when lying down. In more severe cases of heart disease, you may notice your dog stretching their neck out and standing with their elbows flared out in an effort to breathe.
A cough that persists for more than a few days or keeps recurring may also indicate a heart problem. This could be due to an enlarged heart pushing up against the dog's airway or the dog's effort to clear pulmonary fluid (fluid buildup in the lungs), which your veterinarian can assess with a chest X-ray.
Dog behavior changes due to heart problems
Dogs with heart problems often become more lethargic than they used to be. You may notice that your dog sleeps more and plays less than he used to and that they get tired more quickly during walks or play. They may isolate themselves and lose their appetite. Sometimes, people think the lack of energy implies that their dog is just getting older or that it's due to arthritis, which is common in older dogs, but it could actually be a heart problem.
Another potential sign of heart disease is if your dog suddenly begins to walk strangely and unsteadily or faints. You are most likely to see this abnormality during exercise.
Weight loss and body abnormalities in dogs
Weight loss is another common sign of heart disease. In puppies with a heart defect, such as patent ductus arteriosis, you may notice stunted growth. If a heart condition such as pericardial effusion is ongoing, heart muscle wasting may occur.
Heart problems may also cause fluid to accumulate in the body. While fluid in the lungs isn't visible, there can be visible back up in the abdomen. This fluid buildup can cause enlargement of the abdomen, and the fluid buildup can even appear in your dog's legs.
Another potential symptom of heart disease is blue or pale gums and tongue. This is caused by a lack of oxygen and circulation due to heart problems and is definitely worthy of a trip to the veterinarian or veterinary cardiologist. Dogs with heart disease may also have a loss of appetite.
Acute symptoms of heart disease in dogs
Dogs with heart problems may faint or collapse due to a lack of blood flow and oxygen to the brain. This may happen during exercise or while coughing. Heart attacks in dogs are rare, but dogs dying suddenly due to a heart condition is not rare, which is all the more reason to make sure your dog is seen by a veterinarian should you suspect a heart condition. In some cases, you may also be referred to a veterinary cardiologist.
Potential heart problems in dogs
A heart condition is often first diagnosed when your veterinarian hears a murmur while listening to your dog't heart with a stethoscope. Sometimes puppies can have an innocent heart murmur that is due to their blood being a bit thinner than an adult dog's. This is not a true heart problem and resolves on its own. Puppies can also have a murmur due to a congenital heart defect. And older dogs can develop heart murmurs due to valve disease, which is when one or more valves isn't functioning optimally anymore.
Over time with valve disease, dogs may develop congestive heart failure (CHF) because the heart can't pump blood adequately. The mitral valve, which is on the left side of the heart, is commonly affected. Chihuahuas and other small breed dogs are more prone than large breeds.
Another potential cause of CHF is dilated cardiomyopathy (DCM,) which causes an enlarged heart, thinning of the heart muscle (particularly the left ventricle,) and arrhythmias. This is common in boxers, great Danes, certain types of spaniels, and other large breed dogs. If your veterinarian suspects DCM, you can expect them to perform chest x-rays, electrocardiogram (ECG,) and an echocardiogram (heart ultrasound.) They may also refer you to a specialist to perform part of the cardiology workup.
Dogs may also contract heartworm parasites that fill the heart. Heartworm disease is preventable with heartworm medications. However, once a dog is infected, they will require extensive heartworm disease treatment with a series of injections of the drug melarsomine and complete rest.
The bottom line
Dogs can have different forms of heart disease and some may not become obvious until the heart condition has progressed. To ensure a good quality of life, be sure to get your dog regular DVM checkups to assess their heart function. Watch for common signs of heart disease to help diagnose and explore treatment options for your dog as soon as possible. Some symptoms include increased heart rate, difficulty breathing, panting without having exercised, and a persistent cough.