Can dogs have heart attacks? Heart attacks are often an owner’s perception when their dog suddenly dies, but a heart attack is probably not the cause of death in most cases. Heart attacks are rare in dogs.
Clinical Professor of Cardiology at the University of Florida College of Veterinary Medicine explains, “When people use the term ‘heart attack’ they are referring to myocardial infarction, which most often occurs in humans due to coronary disease. Coronary disease, and heart attacks are very rare in veterinary species. Dogs with heart disease most commonly have acquired (degenerative) valve disease (particularly the small to medium-sized dogs) or myocardial disease (large to giant sized dogs).”
Dogs can die suddenly from a heart problem, but that doesn’t mean they had a heart attack.
What Other Cardiac Conditions Can Cause Sudden Signs of Heart Failure or Sudden Death?
“Heart attacks are not usually seen or diagnosed in dogs in a typical ER situation, unlike humans,” concurs Ƶ Chief Veterinary Officer Dr. Jerry Klein, DVM, who worked as an ER veterinarian for over 30 years. “But dogs do have a high percentage of heart disease (cardiomyopathy) and heart failure present in veterinary emergency rooms and veterinary hospitals.”
The most common cause of sudden cardiac death in dogs (and in people) is ventricular fibrillation (V-fib). V-fib occurs when the lower heart chambers contract in a very rapid and uncoordinated manner, so the heart doesn’t pump blood. As a result, the heart doesn’t pump blood to the rest of the body, and the dog can die.
Another type of irregular heartbeat is atrial fibrillation (A-fib), in which the two upper heart chambers beat rapidly and chaotically, uncoordinated with the beating of the two lower chambers. It results in less blood being pumped to the rest of the body, but not to the extent that V-fib reduces it.
Neither V-fib nor A-fib are the same as a heart attack.
What Causes a Heart Attack in Dogs?
While they’re rare, heart attacks do occur in dogs. A heart attack occurs when the coronary artery, which is the large blood vessel that supplies blood to the heart, becomes blocked, depriving the heart of blood and oxygen. The blockage occurs when cholesterol covers the walls of the blood vessel, narrowing the passageway. If any of the cholesterol plaques break open, a blood clot forms at the breakage site. The clot can completely block the vessel, causing a heart attack. Fortunately, dogs don’t have the problems with cholesterol and plaque that people do.
Heart attacks occur from conditions that make blood clots more likely. These include hypothyroidism, vasculitis (inflammation of blood vessels supplying the heart), tumors of the heart or its blood vessels, bacterial infection, and a complication of kidney disease called nephrotic syndrome. However, it’s still rare for any of these to cause heart attacks.
What Are the Signs of a Heart Attack in Dogs?
We’re well-versed in the signs of a heart attack in humans: chest pain, shortness of breath, nausea, dizziness, and arm pain. A dog may have similar signs, but since the dog can’t tell us exactly what he’s feeling, they can be harder to recognize. Here are some common signs of heart attacks in dogs.
Panting
Panting can be a sign of overheating, stress, pain or illness, as well as difficulty breathing. If you see no obvious reasons for your dog panting, and cooling or letting them rest for a minute doesn’t help, this could be an extreme emergency due to a number of causes, and regardless, a reason to race to the emergency vet.
Vomiting
Vomiting can occur in response to extreme pain, stress, or dizziness. Again, this can be due to many causes. However, when your dog is vomiting in conjunction with other possible signs of heart attack, it’s time to go to the ER.
Fever
A fever of over 103 degrees F may accompany a heart attack, but again, is more often indicative of another problem.
Increased Heart Rate
It’s a good idea to practice taking your dog’s pulse in case you’re ever in a position where you need to compare what’s normal. Increased heart rate generally means over 100 beats per minute in large dogs, and 140 beats per minute in small breeds. You can either feel directly over the left chest wall, or inside the upper thigh near the groin. Count the beats in 15 seconds and multiply by four. But again, a fast heart rate can happen secondary to pain or stress.
Front Leg Pain
Just as people may have arm pain during a heart attack, dogs may have front leg pain. Signs of front leg pain in dogs include limping, holding up one leg, or whining when walking.
Physical Weakness
Dogs with a heart attack may seem lethargic, or have difficulty standing or walking. They may even become completely immobilized.
Rigid Posture
Holding the body in a rigid position may accompany a heart attack in dogs.
Confusion
They may seem confused or disoriented, perhaps not recognizing familiar people.
Anxiety
Anxiety: They may be restless, and may pace and whine.
Head Tilt
Holding the head in a tilted position may accompany a heart attack in dogs.
Seizure
Seizures may occur due to the physical stress.
Sudden Death
As with people, sometimes a heart attack causes sudden death. Though it is rare and shocking, it’s unfortunately possible.
Heart attacks are rare in dogs, so more often that not, any of these signs are more likely due to another cause. But especially if several occur together, they could signal a heart attack.
What Should You Do if You Suspect Your Dog Is Having a Heart Attack?
“Little can be done at home, so it is of the utmost importance to receive prompt veterinary attention,” advises Klein.
Keep your dog as calm as possible as you transport them to the closest emergency vet. Call first or have a passenger call as you’re driving. Don’t attempt CPR unless you’re trained in it, as it’s not always advisable and can do more harm than good.
Don’t encourage your dog to eat or drink, as they could vomit and aspirate if they’re having problems with consciousness.
How Is a Heart Attack Diagnosed and Treated in Dogs?
Diagnosis will require listening to the heart and lungs, plus several tests to decide if it’s a heart problem at all, and then to rule out other more likely causes. “The measurement of cardiac troponin test can be used to assist in diagnosing any damage to the heart muscle,” explains Klein. This test can indicate whether the heart is involved, but can’t determine why.
These tests often include:
- Blood tests to check for infections or possibly thyroid deficiency
- Radiographs to determine if the heart is enlarged, has fluid around it, or masses attached to it
- An electrocardiogram to determine if the heart’s electrical impulses or normal and detect any arrhythmias
- An echocardiogram to detect fluid around the heart, masses, heart valve function, heart muscle function, and possibly even clots
Even before your vet can run any tests, your dog may need emergency treatment to be resuscitated and regain normal heart activity. The veterinarian may also give your dog blood thinners to make it easier for their heart to pump blood. Other treatments will depend on which causes your veterinarian identifies.
Treatment may include thyroid replacement therapy for thyroid-deficient dogs, surgery to remove masses when possible, medications to lessen the impact of kidney disease, antibiotics to fight infections, anti-arrhythmic medications to correct arrhythmias, and medications to help the heart pump. In some cases, your veterinarian may advise implanting a pacemaker.
The dog may need to stay at the veterinary hospital until they’re stabilized. Even after they go home, your dog may need to wear a Holter monitor, which records heart rhythms throughout the day for 24 hours. The recording is then analyzed to see how the heart responds during rest and activity.
Treatment most often includes blood thinners to dissolve the clot. Generally, the dog will need to continue to take blood thinners for the rest of its life.
Can a Heart Attack in Dogs Be Prevented?
In humans, we’re taught to monitor our cholesterol, eat heart-healthy foods, and get plenty of exercise, along with having our arteries checked to ensure they’re clear of plaques. Dogs should also eat a healthy diet and get plenty of exercise, but cholesterol doesn’t seem to be the problem for them that it is for us.
“The most important thing owners can do is have their dogs evaluated by a boarded veterinary cardiologist if there are symptoms suggestive of heart disease that arise in their pet (a heart murmur, an irregular heart rhythm, for example), feed a nutritious diet and stay up to date on preventative care (such as heart worm and ectoparasite preventatives),” advises Dr. Sleeper.
It’s essential for your dog to be regularly checked by their veterinarian, and certainly if the dog shows any signs suggestive of heart disease.
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