In the third part of an ongoing study, Dr. Tony Ogg will evaluate tests to determine the effects of blood thinners used to prevent dangerous blood clots in cats. Hypertrophic cardiomyopathy (HCM) is a common disorder where a cat’s heart muscle becomes thickened and may result in a severe complication known as FATE (feline aortic thrombo-embolism), in which a blood clot forms and cuts off the blood supply to the back legs. At least half of cats with this condition die. In an effort to prevent FATE, cats are given the drugs Aspirin or Plavix used as blood thinners in humans. However, the effects of these drugs in cats are not well known and many cats treated with them still die of FATE. This study will measure the efficacy of these drugs using three blood platelet function tests.