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Myocardial Infarction (Heart Attack) in Dogs

Occurrence: very rare
Location of illness: Chest

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

A myocardial infarction, also known as a heart attack, is a serious condition in which the blood supply to the heart is interrupted, leading to damage to the heart muscle. This condition is rare in dogs but can have serious health consequences.

BASICS/CAUSES:

The heart muscle, also called the myocardiumThe myocardium is the heart muscle itself, responsible for the heart's contraction, which enables blood circulation in the body. Diseases of the myocardium can impair the heart's pumping function., requires a continuous supply of oxygen-rich blood to function optimally. This supply is provided by the coronary arteries. If one of these arteries becomes blocked, the myocardiumThe myocardium is the heart muscle itself, responsible for the heart's contraction, which enables blood circulation in the body. Diseases of the myocardium can impair the heart's pumping function. can no longer be adequately supplied with oxygen, leading to damage or death of heart muscle tissue.

The main cause of a myocardial infarction in dogs is a blockage of the coronary arteries, often caused by thrombosisThrombosis is the formation of a blood clot in a blood vessel that can obstruct or block blood flow. Thromboses can occur in veins (venous thrombosis) or arteries (arterial thrombosis). or an embolismAn embolism is the blockage of a blood vessel by an embolus, a blood clot or other substance that travels through the bloodstream and obstructs a vessel. This can lead to tissue damage or death.. ThrombosisThrombosis is the formation of a blood clot in a blood vessel that can obstruct or block blood flow. Thromboses can occur in veins (venous thrombosis) or arteries (arterial thrombosis). occurs when a blood clot forms within an arteryAn artery is a blood vessel that carries blood away from the heart. Unlike veins, which return deoxygenated blood to the heart, arteries transport oxygen-rich blood to the body's tissues., while an embolismAn embolism is the blockage of a blood vessel by an embolus, a blood clot or other substance that travels through the bloodstream and obstructs a vessel. This can lead to tissue damage or death. occurs when such a clot migrates from another location in the body into the coronary arteries.

Other factors that can contribute to a heart attack in dogs include heart diseases, such as cardiomyopathy, as well as systemic diseases that lead to an increased tendency to clot, such as Cushing’s syndromeA syndrome is a group of symptoms that occur together and indicate a specific disease or condition. A syndrome can be caused by various factors and is often complex in its diagnosis and treatment. or diabetes mellitus. Inflammatory conditions of the blood vessels, known as vasculitisVasculitis is the inflammation of blood vessels, leading to changes in the vessel walls, including thickening, weakening, narrowing, and sometimes the formation of aneurysms or blood clots., can also increase the risk.

The most important facts at a glance

A myocardial infarction, also known as a heart attack, can be caused in dogs by thrombosisThrombosis is the formation of a blood clot in a blood vessel that can obstruct or block blood flow. Thromboses can occur in veins (venous thrombosis) or arteries (arterial thrombosis). of the coronary arteries, systemic diseases that affect blood clotting, or serious heart diseases such as cardiomyopathies. Common symptoms include weakness, respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress, vomiting, cough, and an increased heart rate. Rarer symptoms may include fever, lameness, or even collapse. DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. requires a thorough clinical examination, supported by tests such as an electrocardiogramSee ECG., echocardiographyEchocardiography is an ultrasound examination of the heart that assesses the structure and function of the heart valves and chambers. It can provide information about heart size, pumping function, and the presence of heart disease., and blood tests. These tests help to identify abnormal heart rhythms or damage to the heart muscle. Treatment aims to improve blood flow to the heart muscle and prevent further damage. This may include the administration of oxygen, antiplatelet agents, and other medications. Long-term treatment is often necessary to stabilize the dog’s condition. The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. varies depending on the severity of the disease and the speed of treatment. Some dogs may recover completely, while others require permanent treatment. Preventive measures include a balanced diet, regular exercise, and veterinary examinations. Research focuses on the genetic and environmental factors that lead to a heart attack, as well as on the development of new diagnostic and treatment methods to increase the chances of survival.

Causes

ThrombosisThrombosis is the formation of a blood clot in a blood vessel that can obstruct or block blood flow. Thromboses can occur in veins (venous thrombosis) or arteries (arterial thrombosis). of the coronary arteries
Systemic diseases that affect blood clotting
Serious heart diseases such as cardiomyopathies

Symptoms

Very common symptoms:

Common symptoms:

Rare symptoms:

Collapse

The symptoms of a heart attack in dogs can vary and are not always easy to recognize. Often, affected dogs show signs of weakness or exhaustion, which can occur suddenly. Some dogs may show a reduced load-bearing capacity or even collapse.

Other symptoms may include respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress, unusual panting or cough, and a rapid or irregular heartbeat. In some cases, there may also be pale mucous membranes or a blue discoloration of the tongue, indicating an insufficient oxygen supply.

A dog that suffers a heart attack may also show signs of pain, such as restlessness, trembling, or whining. However, these symptoms can be subtle and easily overlooked, especially in older dogs or those already suffering from heart problems.

Diagnosis

The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of a myocardial infarction in dogs requires a thorough clinical examination and can be supported by various diagnostic tests. The veterinarian will first review the dog’s medical historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. and perform a physical examination, looking for signs of heart problems.

An electrocardiogramSee ECG. (ECG) can help identify abnormal heart rhythms that may indicate a heart attack. In addition, echocardiographyEchocardiography is an ultrasound examination of the heart that assesses the structure and function of the heart valves and chambers. It can provide information about heart size, pumping function, and the presence of heart disease., an ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. examination of the heart, can be used to assess the structure and function of the heart and detect possible damage to the heart muscle.

Blood tests can be used to measure cardiac markers such as troponin, a proteinProteins are large molecules made up of amino acids and play an essential role in almost all biological processes. They are necessary for building body tissue, the function of the immune system, and as enzymes for metabolic reactions. that is released when the heart muscle is damaged. A chest X-ray can also be useful to assess the general condition of the heart and lungs.

Therapy

The treatment of a heart attack in dogs aims to improve blood flow to the heart muscle and prevent further damage. In acuteAcute refers to a condition that occurs suddenly and is usually of short duration. In a medical context, it describes symptoms or illnesses that can quickly become serious and require immediate attention. cases, oxygen therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. may be necessary to ensure the oxygen supply to the tissue.

Medications such as antiplatelet agents or anticoagulantsAnticoagulants are medications that slow down or inhibit blood coagulation. They are used to prevent the formation of blood clots and are used in dogs and cats with certain heart conditions or coagulation disorders. can be used to prevent the formation of further blood clots. Beta-blockers or ACE inhibitors can help control blood pressure and reduce the heart’s workload.

In some cases, it may be necessary to treat the underlying cause of the coronary blockage, such as an inflammatory condition or another systemic disease. Long-term treatment and monitoring by the veterinarian is often necessary to stabilize the dog’s condition and minimize the risk of another infarction.

Prognosis and follow-up care

The prognosis for dogs with a myocardial infarction varies greatly and depends on the severity of the disease and the speed of treatment. Dogs that are treated quickly may have a better prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop., while untreated cases can often lead to serious complications.

Some dogs can recover completely after a heart attack, especially if treatment is timely and the underlying cause is addressed. In others, however, the heart disease may become chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time., requiring regular veterinary check-ups and permanent drug treatment.

Prevention

The preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. of a heart attack in dogs focuses on minimizing the risk factors for heart disease. This includes a balanced diet, regular exercise, and avoiding overweight to promote general heart health.

Regular veterinary examinations are important to detect and treat early signs of heart disease. In dogs with a known risk of heart problems, prophylactic drug treatment may be considered to reduce the risk of an infarction.

Treating underlying conditions that can increase the risk of a heart attack is also a crucial step in preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring.. This includes controlling conditions such as diabetes or Cushing’s syndromeA syndrome is a group of symptoms that occur together and indicate a specific disease or condition. A syndrome can be caused by various factors and is often complex in its diagnosis and treatment..

Outlook on current research

Research on myocardial infarctions in dogs is a growing field that focuses on understanding the causes, symptoms, and treatment options for this rare but serious condition. While heart attacks are common in humans, they are less common in dogs. This is partly because the causes are often different and the signs may be more difficult to recognize in animals. In recent years, scientists have begun to look more closely at the genetic and environmental factors that could lead to a myocardial infarction in dogs. They are investigating how certain breeds or genetic predispositions could increase the risk.

Another focus of current research is the development of improved diagnostic techniques to detect heart attacks in dogs earlier and more accurately. Researchers are working to refine imaging techniques such as echocardiographyEchocardiography is an ultrasound examination of the heart that assesses the structure and function of the heart valves and chambers. It can provide information about heart size, pumping function, and the presence of heart disease. and magnetic resonance imaging (MRI)Magnetic resonance imaging is an imaging technique that uses strong magnetic fields and radio waves to create detailed images of the inside of the body. It is used in veterinary medicine to diagnose diseases of the brain, spine, and other organs., as well as to identify specific biomarkers in the blood that could indicate a heart attack. These advances could enable veterinarians to act more quickly and effectively, which would increase the chances of survival for affected animals.

In terms of treatment, researchers are also investigating new drugs and therapeutic approaches specifically tailored to the needs of dogs. This could include adapting treatments that are successful in humans, as well as developing completely new approaches. Particular attention is paid to the safety and effectiveness of such treatments to ensure that they are suitable for dogs.

PreventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. is also an important aspect of research. Scientists are investigating how dietary changes, exercise programs, and other lifestyle-related factors can reduce the risk of myocardial infarction in dogs. By promoting a healthy lifestyle, many cases could potentially be prevented before they occur.

Finally, research into the genetic component of heart attacks in dogs is of great importance. By identifying genetic markers that increase the risk, breeders and veterinarians could make better informed decisions to minimize the occurrence of this disease in certain dog breeds. Advances in geneticsGenetics is the science of genes, heredity, and the variation of organisms. It studies how genetic information is passed from generation to generation and how it influences the development, appearance, and behavior of living things. could lead to a significant reduction in the incidenceIncidence refers to the number of new cases of a disease or condition that occur within a specific time period in a specific population group. It provides information about the risk of contracting the disease. of heart attacks in dogs in the long term.

Frequently asked questions (FAQs)

What is a myocardial infarction in dogs? A myocardial infarction in dogs, colloquially known as a heart attack, is a condition in which blood flow to a part of the heart muscle is interrupted, leading to tissue damage or death. This can be caused by blood clots, constrictions, or blockages in the coronary arteries.
How common is a heart attack in dogs? Heart attacks are relatively rare in dogs compared to humans. The causes and risk factors differ and are often less well researched, which makes diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. more difficult.
What symptoms do dogs show during a heart attack? The symptoms of a heart attack in dogs can be difficult to recognize and include respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress, weakness, collapse, irregular heartbeat, and in some cases sudden death. Due to the non-specific symptoms, a veterinary examination is crucial.
Can all dog breeds suffer a heart attack? Yes, in principle all dog breeds can suffer a heart attack, although certain breeds may have a higher risk due to genetic predispositions. Larger breeds and those with known heart problems may be more susceptible.
What tests do veterinarians perform to diagnose a heart attack in dogs? To diagnose a heart attack in dogs, veterinarians can perform a number of tests, including blood tests, electrocardiograms (ECG), X-rays, echocardiograms, and in some cases MRI scans to assess the condition of the heart.
How is a heart attack treated in dogs? Treatment for a heart attack in dogs may include medications to improve blood flow and stabilize heart rhythm. In some cases, surgical interventions may be necessary to remove blockages or repair the heart.
Can heart attacks be prevented in dogs? While not all heart attacks can be prevented, the risk can be reduced through a healthy diet, regular exercise, and regular veterinary check-ups. Avoiding overweight and controlling pre-existing conditions can also be helpful.
Are genetic factors important in the development of heart attacks in dogs? Yes, genetic factors can play a role. Certain breeds with a genetic predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases. to heart disease may have a higher risk of heart attacks. Research in this area is ongoing and aims to better understand these genetic predispositions.
How does age affect the risk of a heart attack in dogs? Older dogs generally have a higher risk of heart problems, including heart attacks. This is because heart function can decline with age and age-related conditions can increase the risk.
What should I do if I think my dog is having a heart attack? If you suspect that your dog is having a heart attack, you should see a veterinarian immediately. Quick action can be crucial to saving your dog’s life and ensuring the best possible prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop..