The most common type of heart blood clot in cats is aortic thromboembolism. Aortic thromboembolisms are blood clots located within the cat's aorta. When the clot breaks loose and inhibits blood flow to other vessels and tissues in the body, symptoms occur. 

Cats can develop heart conditions that lead to serious complications, such as the formation of blood clots. Blood clots that develop can break loose and travel to other parts of the body. Certain types of heart conditions associated with heart blood clots are hereditary or breed specific. In addition, male cats are more likely to have trouble with blood clots than females. 

The symptoms associated with cardiac blood clots in cats can vary, depending on the cause of the condition. The following is a list of the most common symptoms reported in cats with this condition:

There are several conditions that can cause heart blood clots in cats. Some include:

Additionally, some factors can increase a cat’s risk of developing clots, such as breed and sex. Males, mixed breeds, and certain breeds such as Ragdoll and Birman, are more likely to be affected by the condition than other cats.

Veterinarians must gain information from the cat's owner to help them make a diagnosis. A medical history is taken before examination. Doctors must know if there were any problems at birth or pre-existing medical conditions and how long symptoms have been present. After taking a full and detailed medical history, doctors take vital signs to determine the cat’s overall stability. This includes heart rate, temperature, weight, and respiration rate. In addition, the doctor may take a urine sample to determine if any infection or abnormality is present. Blood tests are typically ordered, including a CBC, or complete blood count, and a chemical profile. High levels of glucose in the bloodstream is an indication the cat is under cardiac stress. Doctors also listen to the heart for unusual sounds.

Doctors also use a variety of diagnostic tests to help them diagnose blood clots and heart conditions. X-rays of the chest often show an enlargement of the heart associated with these conditions. If an aortic thromboembolism is suspected, an ultrasound of the abdomen may be used to confirm it. 

The treatment for cats with blood clots in the heart depends on the cause of the condition. Cats diagnosed with aortic thromboembolism are typically admitted to the hospital. This is because cats with this condition are at an increased risk of going into heart failure suddenly and dying. Doctors may treat these cats with oxygen to enrich levels in the blood and restore free breathing. There are medications that are designed to dissolve heart blood clots in cats. These are known as thrombolytics and are used soon after diagnosis. Cats that do not respond to these medications may need surgery to remove the clot. Doctors admit these cats into the hospital following surgery to administer pain medications and continue monitoring.

The recovery time needed after treating a heart blood clot depends on the severity of the condition and the treatment used. Cats that receive medication and undergo surgery will be monitored in the hospital for a period of time. This surgery is stressful and cats should be placed in a controlled environment after surgery. Other household pets and children should be kept away from the cat until he recovers fully. Many cats find it difficult to eat when being treated for blood clots. For this reason he may need to be placed on a special diet to avoid serious weight loss. After going home, it is important to monitor the cat for bleeding, which can be a side effect of thrombolytic drugs. 

The doctor will continue to monitor the cat's progress every two weeks or so. It is important for the cat's owner and the doctor to work together during this time to prevent relapse. 

Since heart blood clots in cats are serious, the overall outlook is not good. Cats with this condition often have difficulty urinating and breathing. Doctors may recommend euthanasia as the most humane form of treatment if all other methods fail or if the cat is suffering greatly.