Similar to that of humans, a primary cause of mortality in dogs is heart disease. With a number of different heart diseases commonly found in dogs, on top of a number of possible contributing factors, severe heart trauma is relatively common. However, that does not mean we should think of canine heart attacks as identical to human myocardial infarctions. Instead, canine heart attack often manifests in different ways. In a human heart attack, the flow of blood is interrupted suddenly, blocking blood flow to a certain segment of the heart, killing heart cells. While similar trauma can happen in a dog, canine "heart attacks" often take very different paths.
Existing Conditions
Severe heart trauma in dogs is usually related to a pre-existing condition. Often, dogs can be screened for one of these conditions early in life. The most common conditions are an enlarged heart, heart murmur and cardiomyopathy, which is a weakness in the heart muscles. All of these conditions are more common in large dogs than small.
Disease
While an enlarged heart, heart murmur and cardiomyopathy can all be contributing factors in a dog's heart disease, the actual manifestations of trauma often have different causes and labels. Heart failure in dogs is most often directly precipitated by heartworm, inflammation and degeneration of heart valves. Because dogs are rarely subject to the cholesterol build-up, which is at the root of most human heart disease, canine heart trauma is often harder to diagnose, involving a combination of pre-existing issues, degeneration and outside infection.
Symptoms
Except in movies and comics, dogs cannot talk. As such, it is up to their owner to spot the behavior that could indicate a catastrophic heart trauma. Evidence of a heart problem in your pet can include sharp, difficult breathing, evident pain in forelimbs and increased drowsiness. The pain in a dog's chest will often cause him to stretch repeatedly, leaning forward and back on its limb while craning the neck about. Occasionally, a dog will even collapse when under the throes of heart trauma.
Diagnosis
Once you suspect your dog is undergoing heart trauma, it is important to visit the veterinarian right away. Vets can run X-rays or echocardiograms of the chest, which will enable the vet to spot tumors and weaknesses in the heart valve.
Treatment
After a dog heart incident, veterinarians will often prescribe a series of preventative drugs. Anti-arrhythmic drugs are the most common prescription. These pills will steady an abnormal heart beat and may return some normalcy to your dog's life. Treatment for heartworm is another common step taken. Blood pressure medication, similar to that for humans, can help lessen the tension on your pet.
Death
Unfortunately, many pet owners do not receive a warning. Rather than repeated trauma, many dogs are much more likely to have their hearts fail suddenly. Species particularly susceptible to this include sheep dogs, great danes, dobermans and boxers. Analyzing the cause of death after the fact typically involves lab testing of your pet's heart, a procedure that may be prohibitively expensive. Often pet owners must find solace in the fact that their dog's heart failure was sudden and likely due to a congenital problem.