Causes and symptoms of heart attack in dogs

Myocardial infarction in dogs - necrosis (ischemic necrosis) of the myocardium (of the heart muscle) as a result of a mismatch of coronal blood flow (ischemia).

Causes of heart attack in dogs

In dogs, the most common cause of myocardial infarction are hormonal disorders associated with age. Much less common metabolic disorders, due to which the walls of blood vessels thicken due to fat deposits. That is, myocardial infarction in dogs is a rare diagnosis. It is confirmed, as a rule, only at an autopsy after death.

A dog's heart attack can also be triggered by blockage of the coronary artery with an embolus (a substrate circulating in the blood) or a thrombus. Also, a heart attack can cause vasculitis (inflammation of the blood vessels) caused by congenital vascular anomalies or bacterial endocarditis.


Signs of a heart attack are not specific and can occur in many other diseases. Among these symptoms are:

  • cyanosis (cyanosis) of mucous membranes,
  • dyspnea,
  • wobbly sluggish gait,
  • failure to get up and reluctance to move
  • the dog has pain in the chest, but the nature of these pains is not always possible to determine
  • in the most acute period the left elbow area is severely sore for the animal. The pain can last up to several days and cannot be stopped with nitroglycerin. The dog is agitated with fear
  • You can notice arrhythmia and tachycardia, and with the development of heart failure - a decrease in blood pressure

A myocardial infarction can be suggested by a cardiologist during a physical examination with the help of a special examination on an electro- and echocardiograph. However, you first need to exclude heart disease, which are more common and are accompanied by similar clinical signs.

These are dilated or hypertrophic cardiomyopathy, various arrhythmias (extrasystoles and blockades), diseases caused by malfunctioning of the heart valves and other heart pathologies.

The best way to diagnose myocardial infarction is angiography. However, it requires the introduction of an animal in anesthesia, and this is dangerous for a sick dog.

At the first signs of acute heart failure, you should contact a veterinarian, but rather a specialist - a cardiologist. Delay can cost a pet life. The correct diagnosis can be made only on the basis of the necessary examinations of the heart (ECG, ECHO), pressure measurements, blood tests.

Periods of myocardial infarction

In veterinary medicine, five periods of myocardial infarction are clinically distinguished:

  1. preinfarction or prodromal lasts from several hours to a month, although it may be absent;
  2. the most acute period begins with the onset of severe myocardial ischemia and lasts until the appearance of signs of necrosis;
  3. acute period is characterized by the formation of necrosis and the course of from two to fourteen days;
  4. the subacute period is the completion of scar formation, the replacement with necrotic granulation tissue. It can last up to eight weeks from the onset of the disease;
  5. the postinfarction period is characterized by a rumen induration, and the myocardium maximally adapts to the new working conditions within six months from the onset of the infarction


Self-treatment in such a situation is dangerous for the life of the animal. It is necessary to urgently call the vet at home or take the dog to the 24-hour veterinary clinic. Before that, the animal is left in peace and quiet.

In most cases, the dog quickly copes with a myocardial infarction, because its heart has many collateral vessels. Instead of damaged areas, they quickly take over the load.



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