• Opening June 2021 •

Meet The PASE Team

Meet the PASE Team

We are committed to providing exceptional specialty & emergency veterinary care throughout Philadelphia and beyond!

Dr. Al Staab

Brett Harling, DVM

Practice Limited to Internal Medicine
Department Head of Specialty Services

Brett Harling, DVM, is an internist, managing partner, and head of the specialty services at Philadelphia Animal Specialty and Emergency (PASE).

Dr. Harling is a Florida native and completed his Bachelor of Animal Sciences as a gator at the University of Florida. He obtained his Doctor of Veterinary Medicine at St. George’s University, completing three years in Grenada and a clinical year at Ohio State University. After graduation, he completed a small animal rotating medicine and surgery internship at The Animal Medical Center (AMC) in New York City, a specialty internal medicine internship at Animal Specialty Group in LA, a one-year program specializing in minimally invasive diagnostic and therapeutic procedures with the AMC Interventional Radiology and Endoscopy service, and three-year Internal Medicine residency at AMC. Following residency, Dr. Harling worked at MedVet Chicago, practicing internal medicine and establishing an interventional radiology and endoscopy service prior to moving back to the northeast to dedicate his focus towards creating PASE.

In understanding the rapidly changing and advancing veterinary field, he advocates for life-long learning with integration of innovative technology and novel treatment options to practice the highest quality of medicine. Throughout his teaching, Dr. Harling feels lucky to have had many strong influences, often guided by those considered to be leading minds within their respective specialties. Keeping an open ear and open mind has allowed him to gain unique insight, and he has a strong desire to inspire the same passion he has for learning in those around him.

Dr. Harling's professional interests include endoscopy, interventional radiology (minimally invasive diagnostics and treatments for complicated disease processes), management of critically ill patients, and treatment of endocrine diseases (such as diabetes, Cushing's disease, hyperthyroidism, etc.) while developing strong relationships with patients and clients. When not in the hospital, Dr. Harling enjoys playing tennis, exercising with his wife (sometimes), and exploring new areas on runs and hikes. His family includes a spicy Torti cat named Petry and two rescue Frenchies, Kobe and Tofu.

Emily Dozeman, DVM, DACVECC

Co-department Head of Emergency & Critical Care​​​​​​​

Emily Dozeman, DVM, DACVECC is a board-certified emergency and critical care doctor. She is one of the managing partners and co-department chair of the emergency and critical care service at Philadelphia Animal Specialty and Emergency.

Dr. Dozeman attended the Ohio State University where she earned a Bachelor of Animal Science and a Doctor of Veterinary Medicine degree. Following veterinary school, Dr. Dozeman completed a small animal rotating medicine and surgery internship at VCA SouthPaws in Fairfax, VA. She then worked as an emergency doctor in Chicago before deciding to pursue a residency. Dr. Dozeman completed a three-year residency at The Animal Medical Center in NYC.

Dr. Dozeman is experienced in all aspects of emergency medicine and critical care with a particular interest in the management of polytrauma patients, sepsis, and transfusion medicine. She has published multiple articles in The Journal of Veterinary Emergency and Critical Care on whole-body computed tomography in the polytrauma patient. Dr. Dozeman also has a special interest in brachycephalic syndrome and airway management for respiratory crisis (not to mention she owns two french bulldogs herself).

While the excitement of the emergency room and dynamic, challenging cases are the reason Dr. Dozeman has pursued this specialty she also feels that the human-animal bond is one of the main reasons she became a veterinarian. She enjoys being able to make a difference and help families make the best decisions for their pets. Dr. Dozeman also has a special interest inhumane law enforcement and being involved with local rescue groups.

When not treating patients, Dr. Dozeman enjoys being outdoors, spending time with her husband, Brett, and being active. She has two rescue French bulldogs and a cat named Petry.

Erik Zager, DVM, DACVECC

Co-department Head of Emergency & Critical Care

Erik Zager, DVM, DACVECC is a board-certified Emergency and Critical Care specialist, managing partner, and co-department head of the Emergency and Critical Care services at Philadelphia Animal Specialty and Emergency (PASE).

Dr. Zager attended Bucknell University in Pennsylvania where he earned a bachelor of arts in animal behavior. He went on to Cornell University for his doctor of veterinary medicine. After earning his DVM in 2013 he completed a rotating internship in small animal medicine and surgery at the New York City Animal Medical Center. He followed his rotating internship with a specialty internship in emergency and critical care at Tufts University in Massachusetts. He returned to Cornell University for his 3-year emergency and critical care residency. Following his residency, Dr. Zager moved to Hong Kong to set up a critical care department at one of Asia’s few veterinary specialty hospitals. After 3 years in Hong Kong, Dr. Zager returned to the USA to be part of the exciting new PASE team.

Dr. Zager has presented at the International Veterinary Emergency and Critical Care Symposium and has authored and co-authored articles in veterinary journals. During his veterinary education, Dr. Zager participated in multiple community-focused veterinary endeavors, including trips to rural areas of the American Midwest to provide wellness and preventative medicine to disadvantaged communities.

Dr. Zager’s professional interests include the treatment of sepsis, endocrine emergencies, intoxications, and the use of focused ultrasound in the critically ill. Outside of work he enjoys traveling, hiking, and baking. He has two 2 rescue cats, Brando and Otto.

Patricia Mundy, VetMB, MRCVS, DACVO



Dr. Patricia Mundy is our veterinary ophthalmologist, available to perform advanced ophthalmic surgeries. Dr. Mundy earned her Doctorate in Veterinary Medicine degree from Cambridge University in 2005, followed by completing a rotating small animal internship at The Royal Veterinary College in London, England.

Dr. Mundy pursued her interest in ophthalmology by completing a prestigious Fellowship in Comparative Ophthalmic Pathology (COPLOW) at the University of Wisconsin Veterinary / Medical School in 2008. She is one of 22 people worldwide who have been awarded a COPLOW fellowship. Mundy completed a Comparative Ophthalmology Residency at Cornell University in 2012.

Dr. Mundy's interests include clinical, surgical, and comparative ophthalmology as well as ocular neoplastic and inflammatory processes. In her spare time, Mundy enjoys walking her dog Lady Charlotte, participating as an avid member of the sailing community, and enjoying her adventures as an equestrian.

Weihow Hsue, DVM

Practice limited to Cardiology

Dr. Hsue completed veterinary school at the University of California-Davis. He subsequently underwent a year-long small animal rotating medicine and surgery internship at the Ohio State University, and then returned to the University of California-Davis for his 3-year cardiology residency. In the following year, Dr. Hsue pursued a translational research fellowship at the University of Pennsylvania to explore and expand his interests in cardiac electrophysiology and arrhythmic diseases (abnormal heart rhythms).

Dr. Hsue’s professional interests include arrhythmias and the structural and molecular basis of heart disease. He enjoys immersing in other cultures and developing an inclusive and equitable community, having served in the Peace Corps in West Africa, worked on a local farm in Ecuador, and is currently functioning as the Research and Publications Committee Chair for the Multicultural Veterinary Medical Association.

In his spare time, Dr. Hsue enjoys going on backpacking trips with his dog, Diva. Despite being a rescue Chihuahua, Diva has no problems climbing over mountains and cozying up by the campfire.

Tianna Chin, VMD

Tianna Chin, VMD, is an Emergency Veterinarian at Philadelphia Animal Specialty and Emergency (PASE).

Tianna is originally from New York City, where she attended CUNY Hunter College while contracted with the United States Air Force. After receiving an Honorable Discharge in 2014, her love for people, animals, and medicine led her to the veterinary field where she found her passion. She is a recent 2021 graduate of the University of Pennsylvania School of Veterinary Medicine.

Her experience prior to veterinary school included the Bronx Zoo Veterinary Hospital, research at the Animal Medical Center, the ASPCA Shelter Veterinary Hospital, several animal rescues, and volunteering as a farmhand. During her time at PennVet Tianna was an active member of several clubs and served on her class board as a Student Liaison. Most notable memberships include partaking in the indoctrination and part of the board of a Diversity Council and organizing programs through PetSmart Charities for diversity and inclusion within the veterinary field.

Tianna ultimately decided to join PASE and enter Emergency Medicine after falling in love with the challenge and excitement of emergency medicine during her clinical year. Her other interests include Shelter Medicine and Exotic animal medicine. Her special interests include increasing quality care, no matter the circumstances, and positive experiences for both you and your animals.

On her off days, Tianna enjoys tending to her urban jungle and taking pictures of her rescue rabbit Cupid.

Caitlin Weiser, VMD

Dr. Caitlin Weiser grew up in Buffalo, NY where she received her B.S. in biology and ABEC (animal behavior, ecology, and conservation) from Canisius College. She then relocated to Philadelphia where she graduated with her VMD from the University of Pennsylvania in 2021. During her time there, she was an active member of the feline club and developed a love in advocating for a species sometimes considered as second-class citizens.

Caitlin deeply values educating clients to make well-informed decisions on behalf of their companions. She has specific interests in gastrointestinal medicine, toxicology, and trauma cases, and is excited for all of these aspects within emergency medicine. As a lifelong student, she is committed to always expanding her knowledge base with the most recent medical advancements and evidence.

When not working, Caitlin enjoys football season (go bills), exploring the city, and spending time with her cats, Vinci and May, and recently adopted kitten, Barry.

Stephanie Wolstenholme, VMD

Bio Coming Soon!


Mark Massaro, DVM

Operations Manager

Dr. Mark Massaro is a South Jersey native and is excited to be part of the team at PASE!

Dr. Massaro comes from a family of veterinarians. Both of his parents and his older brother are small animal general practitioners, so he spent countless hours growing up learning the ropes at the family practice.

While his passion is caring for dogs and cats, from a young age he also spent a great deal of time volunteering at the Philadelphia Zoo. Here he had the opportunity to work with a number of different species, including everything from ferrets and chinchillas, to lizards and turtles, to armadillos and birds of prey such as red-tailed hawks, great horned owls, and many more!
Dr. Massaro then attended college at the University of Richmond in VA, where he earned his Bachelor of Science with honors and graduated Summa Cum Laude. During his college years, Dr. Massaro also found incredible opportunities to study abroad and experience veterinary medicine around the world as a pre-vet student.

With this, Dr. Massaro traveled to South Africa where he was able to work with the veterinary team at the world-renowned Kruger National Park. This work included research projects involving wild lion, rhino, and elephant populations. Soon after his South Africa travels, Dr. Massaro earned a research grant to travel to Fujisawa, Japan, where he was able to work with a team at one of their veterinary schools (Nihon University College of Bioresource Sciences or NUBS) on vector-borne diseases. These included those transmitted by fleas and ticks, such as Lyme disease.
Upon completing his college career, Dr. Massaro moved on to earn his DVM degree from the Cornell University College of Veterinary Medicine in 2019. He then completed a rigorous 1-year rotating internship in small animal medicine and surgery at CARES (Center for Animal Referral and Emergency Services) in Bucks County, PA. After the internship, Dr. Massaro spent a year in general practice with his family at Village Veterinary Hospital in Medford, NJ. He then decided to try a more managerial role and found a home here at PASE as the "Operations Manager".

Through all of his previous experiences, Dr. Massaro has learned what it takes to work at and operate a successful animal hospital, and is excited to bring that experience with him to PASE! He is especially passionate about creating a positive workplace culture that then extends into exceptional client and patient care.

In his spare time, Dr. Massaro enjoys all kinds of athletics and adventure activities (especially basketball, tennis, beach volleyball, and SCUBA diving), and spending time with his family and friends. His family members certainly include the furry ones! Namely his 2 dogs, Willow and Rosie, and 2 cats, Krepki and Nova.

Stephanie Gordon

Practice Manager

Stephanie Gordon began her career working as a kennel manager while attending the University of the Sciences in Philadelphia. Originally pursuing a doctorate in physical therapy, Stephanie altered her plans realizing her appreciation for the veterinary field. She continued to focus on a degree in biology and a minor in communications. Her passion for managing has lead to her actively pursuing a certification in veterinary practice manager (CVPM). Stephanie has experience working as a technician in general practice, overnight shifts in emergency, and has spent the last 5 years in practice management. When she is not dedicated to the hospital and caring for pets, she enjoys hiking with her rescue dog, Axel, scuba diving, yoga, and numerous amount of outdoor activities.

Rebecca Butterworth

Referral Manager

A University of Delaware graduate, Rebecca has been working as a technician in the veterinary field for fourteen years.

Rebecca launched her career working in General Practice and later moved onto more specific aspects of veterinary practices, including emergency and ophthalmology - both of which she has been involved in for the past four years.

When she’s not working, Rebecca enjoys scuba diving (in open and deep water), baking and cooking, and hanging out with her two rescue pups at home — both of whom she considers to be “her everything”!

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