A common condition that occurs in a cat with CKD patients is heart disease. Giving cats with CKD high rates of intravenous fluid necessary to rid the body of kidney toxins puts these patients at risk for congestive heart failure (CHF). Anecdotally at Foster Hospital, we have observed an improvement in kidney toxin values, appetite and attitude in cats treated with pimobendan for their heart disease. We would like to assess pimobendan can be used safely in cats and if it will benefit cats in the later stages of CKD, IRIS stage 3 or 4. Further investigating our initial clinical observations with a larger study will help establish whether pimobendan could be a novel treatment for cats with CKD. . Benefits could include decreased hospitalization time, improved appetite, improved kidney function, and the ability to treat kidney disease while simultaneously protecting against CHF in patients with concurrent heart disease.