A deficiency of taurine, an essential amino acid, will cause dilated CM in the cat. The restrictive form is associated with an unidentified inflammatory process within the heart muscle. However, many cases of CM are not caused by any of these processes, and we do not understand their origin. Cardiomyopathy is a disease that usually takes several weeks to months to progress to a serious stage. During the early weeks of the disease, the cat will probably look normal.
Cats have the ability to hide serious illness until it reaches a crisis stage.
Therefore, most cats that develop clinical signs of cardiomyopathy will appear to have been ill for only a few days. A few days of inactivity and poor appetite occur first. Just prior to the state of heart failure and death, the cat may become very inactive and exhibit labored breathing. The heart will have an abnormal shape and fluid in or around the lungs may be detected. If a large amount of fluid is present around the lungs, it may be necessary to remove it and take more X-rays because the presence of this fluid interferes with evaluation of the heart.