Our Practice

We are a full-service animal hospital providing comprehensive pet healthcare services in the heart of downtown Portland, OR. Our veterinarians offer a wide variety of medical, surgical and dental services. Our hospital has advanced equipment and technologies, including comprehensive in-house testing for accurate diagnosis, digital x-ray, surgical suite, dental suite, and a pharmacy. We are committed to providing quality care at every stage of your pet's life. From routine preventive care to early detection and treatment of a wide range of conditions and diseases, we have the expertise to provide the highest standard of care for your pet. We also serve clients from Vancouver, WA.

  • Rebecca Sullivan – DVM/Associate Veterinarian


    Dr. Rebecca Sullivan was born and raised in Portland, where she developed an early interest in the well-being of animals. Throughout her life, Dr. Sullivan has volunteered for a number of animal welfare organizations including the Oregon Humane Society, and she continues to volunteer for Portland Animal Welfare Team on her time off. Dr. Sullivan was inspired to pursue an education in veterinary medicine at Oregon State University after she adopted her dog Elephant, who was very ill with pneumonia at the time. Elephant made a full recovery and this friendly little pup now accompanies Dr. Sullivan all around the city and on all her outdoor adventures. Dr. Sullivan is certified in veterinary acupuncture and enjoys keeping up on current veterinary research in order to offer a multi-modal approach to canine and feline wellness. When not practicing veterinary medicine Dr. Sullivan enjoys rock climbing, backpacking, home improvement projects and gardening.

  • Thomas Mackowiak – DVM/Practice Owner


    As a charter member of the new breed of veterinarians, Dr. Mackowiak brings something to the table that few vets can match. From his attention to detail to his thoughts behind an individualized approach to pet care, he has started changing the standard of care by opening Heartfelt Veterinary Hospital.

    A true man of the world, Dr. Mackowiak is at home in multiple languages, multiple cultures, and multiple disciplines. Having grown up in Germany, Thomas studied law in Chile, switched careers mid-stream, emigrated to Oregon to work on a veterinary research project, completed his studies at Oregon State University.

    Thomas’ familiarity with so many varied cultures has given him an uncommon level of “emotional intelligence”, which allows him to see and sense things most other veterinarians miss. Combined with his professional expertise, Dr. Mackowiak combines these intangible skills to bring a multiplier effect to veterinary medicine, leading to a wonderfully constructive relationship between the Heartfelt team, your pet — and you.

    A 2010 graduate of the College of Veterinary Medicine, Oregon State University, Dr. Mackowiak maintains veterinary licenses in Washington and California as well as Oregon.