Help! My Cat Appears to Faint

A loss of consciousness is always an emergency

Q. My one-year-old domestic shorthair spayed female cat seems perfectly normal and then, without warning, she’s passed out on the floor. She’s not out for long, but I don’t think this is normal. What would cause such a thing?

A. Fainting, which your veterinarian will call “syncope,” is a temporary loss of consciousness followed by a spontaneous rapid recovery. It’s usually a symptom of illness caused by a lack of sufficient blood flow to the brain.

Cats with cardiac or central nervous system diseases, which occur more often in cats as we grow older, can cause fainting. Among the common causes are:

-Heart-muscle diseases, like cardiomyopathy


-Irregular heartbeat (arrhythmia)

-Liver disease

-Low blood sugar (hypoglycemia), more common in kittens

-Nervous system disorders

-Neurologic problems, like epileptic seizures

-Sudden drop in blood pressure

If your cat faints, write down the time, how long she was unconscious, what she was doing at the time, and other symptoms. If you can get a video, that’s even more helpful to your veterinarian.

“Your veterinarian will review your cat’s health history and perform a thorough physical examination with baseline blood work, including serum biochimestry and glucose levels,” says cardiologist Bruce Kornreich, DVM, Associate Director of the Feline Health Center at Cornell.

Because arrhythmias may be a cause of fainting, your veterinarian may suggest your cat wear a Holter monitor to obtain a 24-hours cardiogram to check the heart’s electrical function. “Inappropraitely rapid rates can be treated with drugs, while slow heart rates can be corrected with pacemakers,” says Dr. Kornreich.

If your cat has fainted, avoid stressing his heart by restricting activity and keep him as quiet as possible until your veterinarian has determined the cause of the fainting, says Dr. Kornreich.