The cat in this case had restrictive cardiomyopathy that was revealed from a gallop heart sound, which was noted on a physical exam 6 months before presenting to the Cornell University Hospital for Animals (CUHA). This caused an arterial thromboembolism that lodged in the terminal aorta. Over the next few days, the cat succumbed to hyperkalemia associated with reperfusion injury from lysis of the clot, and sudden return of blood flow to the hind limbs.