Heart Attack in Cats
A “heart attack” is the term commonly applied to people who have suffered a myocardial infarction (MI), most commonly related to coronary artery disease. The myocardium is the muscular tissue of the heart; it receives nutrients and oxygen from the coronary arteries. The coronary arteries are small blood vessels in the myocardium which bring blood from the aorta, the main artery of the body.
If the coronary arteries become narrowed or blocked, usually with hardened plaques of fats, this can interrupt blood flow to the myocardium resulting in an infarction. The “infarct” is the area of the myocardium which is sick from the lack of blood supply. This area of muscle stops functioning well and may become the source of abnormal heart rhythms (arrhythmias). Depending on the size of the infarct, the area of the heart involved and whether the blockage is partial or complete, a myocardial infarction may be mild (chest pain) or severe resulting in heart failure or even death.
It is very unusual to identify a myocardial infarction in a cat, most likely because of the differences in the way fats are processed by the body and dietary factors. This means that cats rarely, if ever, suffer from true heart attacks. Even on a fatty diet, cats are very resistant to coronary artery disease. In theory, cats with diabetes may be at higher risk for coronary artery blockage but the risk of MI is miniscule! Myocardial infarction due to coronary artery blockage has been suspected is some cats with cardiomyopathy (heart muscle disease) based on the pattern of thinning of heart muscle in certain areas of the heart. Similar patterns of thinning of the heart muscle are noted in people documented to have coronary artery disease. The cause of blockage in cats is probably related to small blood clots formed in the heart secondary to the underlying cardiomyopathy, rather than related to any dietary factors and fat clogging of the blood vessels. This theory remains to be proven.
The term “heart attack” is often misunderstood in relation to dogs and cats. The term is typically used to either define a collapsing episode (more accurately termed a syncopal spell or syncope) or to describe sudden death of an animal, neither of which are really heart attacks.
When sudden death occurs in a pet, there are many different causes. A heart attack is actually a very unlikely cause. To try to determine the cause of sudden death, your pet should be presented as soon as possible to a veterinarian for a post-mortem (autopsy) examination. This may require referral to a veterinarian who specializes in pathology.
Since a fainting or syncopal spell is often mislabeled as a heart attack, diagnostic tests and treatment are aimed at finding the underlying cause of the fainting and not specific for a “heart attack”.
Diagnosis of Heart Attack in Cats
Treatment of Heart Attack in Cats
Treatment for syncope (a fainting spell) which his often misdiagnosed as a heart attack depends on the underlying cause.
Do not attempt to deliver CPR to your pet, unless you have specifically been trained to administer pet CPR. These attempts are more likely to result in injury to the pet than improve the condition. Remember, true heart attacks are very rare in dogs and cats and is unlikely to be the cause of your pet’s collapse.
If your pet collapses, try to place a hand on his chest and determine if the heart is racing or is very slow. Time the event and make observations/notes as to what the pet is doing. Be careful, your pet may not recognize you during the spell, and could be aggressive. If the episode is not over within three or four minutes, carefully transport your pet to your veterinarian or local veterinary emergency clinic.
Your pet should be examined by your veterinary as soon as is safely possible after an episode. For an animal with repeat episodes, you should keep a log of the episodes (date, time, duration, etc) to show your veterinarian.