Meet Our Team

Karen "Kate" Isselbacher M.D.

FOUNDER & CEO

Karen T. Isselbacher, M.D., is the founder and CEO of Exceptional Health. With a strong lineage of physicians in her family, medicine is an inherent part of her life. Dr. Isselbacher’s unwavering dedication to patient care has earned her a reputation for establishing profound personal connections with those she treats. Many of her patients speak of the comfort, security, and trust they feel under her compassionate care.

Dr. Isselbacher graduated with honors from Harvard University, earning an A.B. Degree in 1981. Subsequently, she obtained her Medical Degree from Boston University School of Medicine in 1985. She completed her medical internship and residency at Mount Auburn Hospital, a prestigious Harvard teaching hospital in Cambridge, MA, in 1989. Additionally, she holds the esteemed title of diplomate of the American Board of Internal Medicine.

From 1991 to 2001, Dr. Isselbacher served as an active member of the medical staff at Mount Auburn Hospital, where she practiced primary care medicine. In 2001, she joined the Department of General Internal Medicine at Brigham and Women’s Hospital in Boston, continuing to provide exceptional primary care until 2006 in a bustling group practice situated in Newton Corner.

Throughout her tenure from 1991 to 2012, Dr. Isselbacher also served as a respected faculty member at Harvard Medical School. She took great pleasure in mentoring students and resident doctors, offering her expertise and guidance. While she has a particular interest in women’s health, Dr. Isselbacher wholeheartedly cares for both men and women.

With over 30 years of experience in primary care, Dr. Isselbacher’s commitment to improving & maintaining health of each patient remains unparalleled. The quality of medical care she provides continues to surpass expectations, establishing her as a true leader in the field.

Li Tso M.D.

ASSISTANT PROFESSOR OF MEDICINE HARVARD MEDICAL SCHOOL

Dr. Li Tso graduated magna cum laude from Harvard University with a degree in chemistry. He went on to earn his medical degree from SUNY Stony Brook School of Medicine, where he graduated first in his class and was recognized as a member of Alpha Omega Alpha, the National Medical Honor Society.

Dr. Tso completed his internal medicine residency and fellowship training in nephrology at Massachusetts General Hospital, where he practiced as a physician for almost 30 years. His dedication to excellence and commitment to patient care have earned him The Partners in Excellence Award from Mass General Brigham, a prestigious accolade that honors individuals who consistently go above and beyond to support the healthcare system’s mission. In addition to his clinical practice, Dr. Tso holds the position of Assistant Professor of Medicine at Harvard Medical School, where he imparts his knowledge and expertise to future physicians. Since 2010, he has also served as a team physician and internist for the New England Patriots, demonstrating his proficiency in sports medicine.

Dr. Tso possesses a wide range of clinical interests, including preventive medicine, renal disease, cardiology, and sports medicine. His extensive experience and expertise in these areas make him an invaluable asset to our patients and our practice. We are confident that under Dr. Tso’s care, our patients will receive exceptional medical attention and compassionate support.

Christine Harrington M.D.

INTERNAL MEDICINE SPECIALIST

Dr. Christine Harrington graduated Magna Cum Laude from Brown University with a B.A. in Cognitive Science. She earned her medical degree from the Perelman School of Medicine at the University of Pennsylvania. After earning her degree, she completed her residency in internal medicine at the University of Pennsylvania Hospital.

Dr. Harrington worked at Beth Israel Deaconess Medical Center for 16 years. There, she served as a Harvard University Instructor, educating and mentoring medical students in primary care. She worked passionately to improve high-quality healthcare delivery. She served on the Affiliated Physicians Group (APG) Provider Advisory Board and the Clinical IT Leadership Committee. In these roles, she played a pivotal role in implementing a new electronic medical record system for APG.

Following three years spent establishing a new primary care practice at Atrius Health, Dr. Harrington joined Newton Wellesley Hospital in 2019. Since then, she has remained a committed member of the Department of Internal Medicine.

Dr. Harrington’s clinical interests include preventive medicine, women’s health and the long-term care of cancer survivors. She is also certified in Lifestyle Medicine. This field focuses on evidence-based methods like diet, exercise, sleep, and stress reduction. These methods help prevent, treat, and reverse chronic diseases.

Outside of medicine, Dr. Harrington lives by her advice. An avid runner, biker, swimmer, skier, and hiker, Dr. Harrington loves spending time outdoors with her dogs. In addition to her active lifestyle, she is a passionate cook and an even better baker. Confident in her balanced approach to nutrition, she enjoys tofu and chickpeas. However, she will never give up her home-baked M&M cookies.

Dr. Christine Harrington is passionate about helping her patients not only live longer but also healthier lives. She looks forward to working with each patient in a concierge setting. Together, they will create a personalized plan. This plan will address both current and future health care needs.