Heart Attack in Cats

Coronary artery disease and blockage are atypical in cats due to the way that a cat's body processes consumed fats. Because of this, heart attacks in cats are extremely rare. When a heart attack does occur, however, it can be fatal.

The myocardium is the muscular tissue that makes up the heart muscle. When a heart attack, or myocardial infarction, occurs the myocardium is cut off from receiving vital oxygen and nutrients from the coronary arteries. This typically happens due to a blood clot. Without this oxygen, parts of the heart die prematurely, which causes the heart to become weak and lose its regular function.

Symptoms of a heart attack typically appear suddenly. These symptoms include:

• Extreme weakness
• Lethargy
• Fainting or collapse
• Loss of appetite
• Vomiting
• Increased or slowed heart rate
• Heart palpitations or skipped beats
• Low-grade fever
• Inability to walk (lameness)
• Seizures
• Hyperactivity
• Sudden death

A heart attack occurs when the blood flow is cut off from the myocardium. This will either occur due to a blood clot (thromboembolism) or heart muscle disease (cardiomyopathy).

The veterinarian will need the cat's complete health history, which will include any history of heart disease, a detailed list of symptoms and an approximate date and time when the symptoms first began. The veterinarian will then physically examine the cat, listening to its heart and breathing with a stethoscope, taking its pulse and blood pressure and looking for gait abnormalities that could signal a blood clot. The veterinarian will pay close attention for any signs of heart murmurs or muffled heart sounds that are indicative of fluid in the pericardium, which is the sac that surrounds the heart muscle. 

A biochemical profile, complete blood count, and a urinalysis will be done. These labs can help the veterinarian identify systemic conditions that could have caused the heart attack or help the veterinarian rule out other conditions that have similar cardiac symptoms, such as hyperthyroidism. These lab tests may show a high white blood cell count as a result of an infection or high liver enzymes that are indicative of a liver problem.

An electrocardiogram (EKG) and an echocardiogram (ECG) will be performed on the cat. An EKG looks at the heart's electrical activity and can help identify blockages and abnormal heart rhythms. An ECG is an ultrasound of the heart muscle. The ECG will look for abnormalities of the heart valves, the pericardium, and any heart muscle diseases. The veterinarian may also take a chest X-ray of the cat in order to view any abnormalities in the lung cavity.

If the hospital tests are inconclusive as to the condition that caused the heart attack to occur, the veterinarian may want the cat's heart rate monitored for a longer period of time. In this case, the cat may be fitted for a Holter monitor, which will record all heart activity for a 24 hour period, or an event monitor, which will record the heart activity during events such as collapsing.

Medication

The cat might be given medication in the hospital to try and dissolve a blood clot and restore blood flow to the heart. The veterinarian may prescribe medications in order to treat the cat's underlying condition that caused the heart attack to occur. Antiarrhythmic drugs, such as beta-blockers or digitalis, can help slow the cat's heart rate down to an appropriate level. 

Oxygen Therapy

Cat's who have had a heart attack will need to receive oxygen therapy in the hospital in order to ensure that enough oxygen is being delivered to the body. The oxygen will be given to the cat via a nasal cannula or a face mask. Oxygen therapy will continue until the heart is able to function properly and deliver oxygen to the body in its own.

Pacemaker Implantation

Cats who have a slow heart rate as a result of the lost tissue during the heart attack may need to have a pacemaker installed. The pacemaker will be placed into the cat's abdomen during surgery. The lead will then be surgically attached to the outside of the heart via a small incision in the diaphragm. The pacemaker works by sending a small electrical signal to the heart, which will keep it beating at a normal pace.

The cat's prognosis will depend on the severity and length of the heart attack as well as the successful treatment of the underlying condition that caused the heart attack to occur. The cat will need to regularly follow up with the veterinarian to monitor the heart rate through EKG tests. If the veterinarian sent the cat home with a Holter or event monitor, instructions will need to be followed in order for the condition to be properly diagnosed. The cat will need to rest while it recovers after a heart attack in order to recover properly.

If a cat collapses at home, it's important to never administer CPR unless specifically trained in pet CPR as this could cause additional injury to the cat. If a cat does collapse, it's important to gently feel the cat's chest and note any heart irregularities, such as a fast or slow heartbeat, and report this to the veterinarian.