Stormie, a 4-year-old female Siamese cat, has had a history of heartworm disease since she was adopted at 1 year of age. She and her owner live in Los Angeles, but were visiting family in the Bay Area when she developed pelvic limb lameness. Fearing she had fallen off something or down a staircase, Stormie’s owner brought her to a local veterinary emergency room in Berkeley, where she informed them of the history of heartworm disease. After ultrasound showed a suspected heartworm in the arterial system, and a heartworm antigen test resulted in a strong positive, Stormie’s owner was advised to bring her to specialists at the UC Davis veterinary hospital.