Heights Hospital For Animals

1865 Commerce St
Yorktown Heights, NY 10598



Our Team


Dr. Mark Sebetic:

Dr. Mark Sebetic grew up on Long Island in NY. He started working at the Port Washington Animal Hospital when he was a junior in High school. He began as a volunteer and worked his way through the different jobs at an animal hospital. He attended undergraduate school at Muhlenberg College and graduated from The University of Florida with a degree in Microbiology and Cell Science. He went to Veterinary School at The University of Tennessee where he met Drs. Delaney and Groblewski. The 3 graduated in 1988.

After graduating he worked on Long Island for 6 years and in 1994 he bought Harlem Valley Animal Clinic. He remained in contact with Drs. Delaney and Groblewski and in 2003 they became partners and purchased Heights Hospital For Animals. In 2008 he opened Kent Animal Clinic. His special interests include surgery and dermatology. He remains deeply committed to a compassionate and common sense approach to his patients and clients.

Together with his wife Cathy and son Michael he lives in Kent, CT. They have 3 dogs, 2 Labradors and 1 King Charles Spaniel, and 3 cats. He serves as the treasurer of The Kent Memorial Library and is the vice chairman of the Kent Board of Finance. He is an avid golfer and plays regularly.

Dr. Dave Groblewski:

Dr. Dave Groblewski is a native of Northeastern Pennsylvania. He and Dr. Delaney met in high school and then both got their undergraduate degree in biology at Wilkes University. Although his father and uncles were renowned physicians in the community, Dr. Dave decided to pursue a career in veterinary medicine. He attended the University of Tennessee Veterinary school, and together with Drs. Delaney and Sebetic graduated in 1988. Dr. Dave worked at an emergency practice in Tennessee before moving to the New York area. In 2003 the three doctors became partners at Heights Hospital for Animals in Yorktown Heights, NY and Harlem Valley Animal Clinic in Dover Plains, NY.
Dr. Dave’s special interest is internal medicine where he relies on his experience and expertise in solving complex medical issues.
In his spare time he enjoys many outdoor activities including golf, fishing for steelhead trout at the Salmon River in upstate New York, and hiking with his wife and favorite dog, Scout.

Dr. Nancy Delaney 

Dr. Nancy Delaney was born in Northeastern Pennsylvania. After meeting Dr. Dave in High School, they both studied biology at Wilkes University then went on to veterinary school at the University of Tennessee. Together with Dr. Sebetic they graduated in 1988. After completing an internship at the Animal Medical Center in New York City, Nancy settled in the Hudson Valley with her husband Dr. Dave.

In 2003 the three doctors became partners at Heights Hospital for Animals in Yorktown Heights and Harlem Valley Animal Clinic in Dover Plains, New York.
Dr. Delaney was blessed to have a loving and supportive family who encouraged her to pursue a lifelong dream of becoming a veterinarian. She uses genuine compassion and empathy in helping both her patients and clients. Her special interests are internal medicine and dentistry.
Her favorite activity is hiking in the mountains with Dr. Dave and their beagle, Scout!


Jean Chutka-Gazzoli 

Jean Chutka-Gazzoli was originally a client of Dr. Sebetic for 5 years with her 2 Labradors Sam and TJ. Then in 2000 she started working as the receptionist at Harlem Valley Animal Clinic. She took a brief hiatus when her daughter Annika was born in 2001. She returned shortly thereafter and has been with us since. She started working in the Kent office when it opened in 2008 as well as continuing at Harlem Valley Animal Clinic.

Jean together with her husband Todd live in Dover Plains with their daughter Annika. In addition they have 2 dogs, a Doberman named Nick and a Labrador named Jonas. They also have 2 cats Ceasar and Suzy.


Kathy Klein 

Kathy is a long time resident of the Hudson Valley. She graduated from Delhi University with a degree in Veterinary Science Technology. She then became a Licensed Veterinary Technician. She has worked at a number of Veterinary Hospitals gaining a wide range of knowledge and expertise in the care and nursing of animals. Her relationship with Drs. Delaney and Groblewski has spanned over 20 years. She promotes the highest standard of care for her patients as she continues to educate herself.

She has a cat named Blackie and her interests away from work include horseback riding and kayaking.


Cortney Lakowitz

Cortney grew up in New Jersey and moved to New York in 2004 when she began working at the Harlem Valley Animal Clinic. Previously she had worked for 5 years in a pet store. Her amiable personality makes her a key figure in keeping our hospital organized and running smoothly. She has a special way of making our patients and their owners feel comfortable and at home.

She lives in Dover Plains with her Pit Bull mix Khai and her cat Toretto. In her free time she enjoys traveling and taking spiritualistic classes. She has received her attunements in Reiki healing.


Donna Christiansen

Donna grew up in Dover Plains and married her husband Mark, who grew up in Wassaic. They were long time clients of Dr. Sebetic’s before Donna began working at Harlem Valley Animal Clinic in 2007. She is in charge of caring for the hospitalized and boarding animals. She has a very caring and empathetic way of making sure that each animals’ needs are being met.

She lives in Dover Plains with her husband Mark and their 2 sons, 9 cats and 1 dog. She enjoys gardening, sewing and dancing.


Kimber Hadden

Kimber grew up in Poughkeepsie NY. She worked in a pet store caring for small and exotic animals for 4 ½ years prior to joining us at Harlem Valley Animal Clinic in 2011.

As well as assisting the doctors and technicians, she is one of the employees in charge of the kennel, thus she plays a vital role in the well-being of all our patients.
Her fur babies include rabbits, ferrets, hedgehogs, and a German Shepherd. She enjoys being outside playing with her animals and reading.