A dog's heart attack is a life-threatening condition that can affect animals of any age and breed, sometimes without warning.
It is an absolute veterinary emergency, with a poor prognosis even if treated quickly. Nevertheless, it is still possible to save a dog suffering from a heart attack by adopting the right actions at the right time, which implies knowing how to detect the symptoms of this condition as soon as possible.
What is a heart attack in dogs?
As in humans, a dog's heart attack is a dysfunction of the blood circulation caused by a myocardial infarction. The myocardium is the muscular part of the dog's heart, and an infarction is an injury caused by the blockage of an artery.
Thus, a myocardial infarction occurs when an artery becomes blocked, depriving the heart of its blood supply, and thus of its oxygenation. It should be noted that all of the dog's organs can be affected by a heart attack. Nevertheless, myocardial infarction is rare in dogs - and cats.
In fact, myocardial infarction in dogs is rarely referred to as a heart attack, but is more commonly used to describe various phenomena that cause sudden cardiac dysfunction, particularly heart failure.
Stress and heart attacks in dogs
A dog under severe stress can suffer a heart attack, especially if it is predisposed to or already has heart disease. Thunderstorms, fireworks, airplane rides - or even car rides - are all events that can cause intense stress, resulting in an increased heart rate, sometimes to the point of fainting.
Excessive effort is also a potential cause of cardiac arrest, especially in hot weather, in dogs who do not know how to stop and do not hesitate to exceed their limits with great enthusiasm, until they feel sick.
We point the finger here at tenacious terriers, and in particular Fox Terriers, Jack Russels and Staffies, champions in their category, capable of chasing a ball until they are completely exhausted.
Aging heart and heart attack in dogs
The heart, like all of the dog's organs, ages with time and tends to become more fragile with age. The heart muscle may tend to contract less well (cardiomyopathies), the heart valves become less tight (endocardiosis) and the arteries tend to narrow (stenosis).
Although older dogs rarely die of spontaneous cardiac arrest, they may be predisposed to heart attacks during stress, strenuous exercise or hot weather.
Older dogs with other predispositions, such as genetic heart defects, are particularly at risk.
Genetic abnormalities and heart attacks in dogs
Hereditary heart defects are relatively common in dogs, especially in purebred animals. In order to detect them in time and to be able to take care of your pet taking into account its possible predispositions, it is advisable to always carry out a health check-up at the time of its adoption, whether it is young or old.
Some genetic cardiac pathologies have no consequences (pulmonary stenosis), but others deserve a special follow-up to reduce the risk of a heart attack. The most common anomalies are stenosis (narrowing of the arteries), defects in the connections between the atria or ventricles, valve dysplasia (malformation), and persistence of embryonic vessels that are supposed to disappear at birth.
These different disorders can also be combined with each other (tetralogy of Fallot), which does not necessarily mean an increased risk of a heart attack. Most often, young dogs with genetic heart defects do not show any symptoms, and the defect is discovered incidentally during a routine consultation, usually as a result of the detection of a heart murmur with the stethoscope.
When heart diseases in dogs are not due to genetic abnormalities, they are called "acquired". These can be just as insidious as hereditary disorders and may not cause any symptoms. Degenerative Valve Disease (DVM) is the most common heart disease in dogs, especially in the Cavalier King Charles, which is prone to it. Small dogs under 10kg are the most affected by this disorder.
MVD consists of a degeneration of the valves that evolves slowly (over years). The valves gradually deform, becoming less airtight, causing blood to flow back to the left atrium. Under the pressure, the atrium will also deform. As the pressure in the circulatory system increases, blood plasma will flow through the vessel walls to flood the lungs. This leads to pulmonary edema, which most often results in cardiac arrest.
Dilated cardiomyopathy (DCM) is almost as common as MVD, but this time it is more common in large breed dogs, with canine patients with this condition averaging 38kg. The Boxer, Doberman and Cocker Spaniel are predisposed to the development of particular forms of this disease. CMD consists of a thinning of the walls of the heart resulting in dilatation of its different chambers and a loss of power of contractions.
As a result, the blood flow decreases and the organs are poorly oxygenated. This can lead to discomfort and, as with MVD, the outcome is pulmonary edema, which can lead to cardiac arrest. Other cardiac, metabolic or bacterial diseases (pericardial effusions, tumors, endocarditis, etc.) can cause dysfunction leading to a heart attack.
Parasites and heart attacks in dogs
If there is a heart disease that can give nightmares, it is undoubtedly the Dirofilariosis, or heartworm disease, caused by the infestation of Dirofilaria Immitis. Dirofilaria Immitis is a roundworm transmitted by mosquito bites that colonizes the dog's arteries before infesting its heart muscle. The mosquitoes responsible for these contaminations live mainly in hot areas, along the Mediterranean and in the French overseas departments and territories.
In case of massive infestation, the veins of the dog can be obstructed by the worms (measuring up to 30cm long), which generates a severe anemia and a state of shock, which can result in a heart attack.
Symptoms of a heart attack in dogs. A heart attack in dogs is often difficult to detect, which leads to late treatment and a poor prognosis for the animal. The animal is usually a victim of a sudden malaise, often preceded by breathing difficulties. However, there are symptoms that may indicate heart disease (e.g., MVD or CMD) that predisposes the dog to a heart attack.
A heart murmur, imperceptible to the owner but detectable by a veterinarian during a routine visit, is typical of a genetic, parasitic, bacterial or acquired heart condition. A dog that is coughing, short of breath rapidly, appears tired, or has difficulty breathing should be taken promptly to a veterinarian to investigate cardiac pathology.
Nervous symptoms (sudden paralysis of the hind limbs) may also be associated with cardiac abnormalities affecting oxygenation of the brain, as may abdominal effusions (ascites).
What to do if your dog has a heart attack. If your dog has a heart attack, the best thing to do is to take him to a veterinarian as soon as possible so he can be treated. Hospitalization as soon as possible is the only way to save your dog. Quickly check if your regular veterinarian is open: he is the best professional to take care of your dog. If your veterinarian is not available, go immediately to the nearest veterinary emergency room.
Throughout the trip, try to reassure your dog so that his heart rate does not increase further due to stress. Do not attempt to get him to eat or drink, but wrap him in a blanket to keep him warm - unless the heart attack appears to have been caused by heat stroke.
Note that human resuscitation techniques are not appropriate for dogs. There are first aid techniques specifically designed for our four-legged friends, but these are not improvised: unless you have mastered them, it's best not to attempt them. Also, unless you are very far from any veterinary structure, it is better to take your dog to a veterinarian instead of trying to do canine first aid.
Treatment and prognosis of heart attacks in dogs. Unfortunately, heart attacks are often fatal, especially when the animal has already lost consciousness. Nevertheless, some dogs can be resuscitated and manage to pull through. However, when you detect symptoms of a heart attack (coughing, fatigue, shortness of breath, difficulty breathing, etc.) it is not too late, and the animal has a good chance of surviving if it is quickly taken care of by a veterinarian.
When heart disease is diagnosed early, the prognosis of the animal is often good in the short and medium term, allowing the dog to live for years in normal conditions. Medication can be used to reduce the pressure on the heart to reduce the risk of pulmonary edema, myocardial fibrosis and heart attack, as well as to strengthen heart function.
There are also surgical procedures that can be used to treat conditions in dogs (such as valve repair), but these are still not widely performed and can only be performed in facilities with state-of-the-art equipment.
Prevention of heart attack in dogs. The best way to prevent a heart attack in dogs is to have annual check-ups, during which the veterinarian will make sure that there are no genetic or acquired heart defects. If such abnormalities are detected, early treatment will be implemented to give your dog a good prognosis.
In the absence of such pathologies, when the dog comes out of his check-up with all the lights in the green, the risk of a heart attack is extremely low. However, it is important not to expose your dog to stressful environments or conditions that can lead to heart attacks, whether he is predisposed to them or not.
To that end, never leave your dog alone in a car, even for a few minutes, even when the temperature seems reasonable or the vehicle is parked in the shade. Owners of anxious or fearful dogs should also ensure that they provide a safe environment for their four-legged friends, especially when fireworks, thunderstorms or other stressful events are forecast.
For dogs that can't stand transportation, it may be a good idea to take a small painkiller prescribed by a veterinarian before leaving on vacation, so that the trip can be made in a calm environment. Finally, it is important to deworm your dog and protect him from mosquitoes to avoid him being contaminated by parasites that can cause heart damage, especially when you live or stay in high-risk geographical areas.
How do I know if my dog is having a heart attack?
The symptoms of a heart attack are equivocal: the dog suddenly feels faint, usually preceded by breathing difficulties, often resulting in a loss of consciousness. It is especially useful to know the warning signs of a heart attack. Unexplained coughing, exacerbated and/or long-lasting fatigue, lack of energy and breathing difficulties can indicate heart problems that could lead to a heart attack.
My dog has a heart murmur, can it have a heart attack?
A heart murmur can be a symptom of a heart condition that predisposes the dog to heart failure. However, in most cases, the heart murmur does not reveal anything serious and the dog can live his whole life with this abnormality without suffering from it. The dog will still require increased monitoring to ensure that the condition does not progress.
What is a dog heart attack?
A heart attack is an infarction (blocked vessel) of the myocardium (heart muscle). The blood does not circulate properly and the heart is deprived of oxygen. A myocardial infarction is rare in dogs, but a heart attack can occur when other blood circulation problems cause the heart to malfunction or even stop completely.
What should I do if my dog has a heart attack?
If your dog has a heart attack or shows symptoms that indicate a heart condition (shortness of breath, coughing, fatigue, effusion, etc.), it is necessary to take him to a veterinarian urgently. A heart attack is an absolute emergency, and only the fastest possible treatment can give your dog a favorable prognosis.
Can you give a dog CPR?
There are specific resuscitation methods to try to revive the heart of a dog in cardiac arrest. However, they are different from those used in humans, not always effective and difficult to perform. In fact, it is not advisable to try to resuscitate your dog yourself, especially if you are not familiar with emergency procedures, unless you have no way of getting him to a veterinarian.
Seeing your dog have a heart attack is a traumatic experience for the owner, but fortunately it is an extremely rare phenomenon that can be avoided in most cases. Dogs that suffer a heart attack are usually dogs with heart problems that can be detected early and managed with the right veterinary treatment.
In fact, by giving your pooch an annual veterinary checkup and keeping him safe from heatstroke, you can drastically reduce the already low risk of a heart attack.