Our Team

The Princeton Longevity Center Staff Brings The Highest Levels Of Expertise To Your Care

All our physicians are American-trained and board-certified.

The Princeton Longevity Center’s staff’s knowledge and experience are unmatched by any other preventive medicine center in the region.


David A Fein, MD


John Rumberger PhD, MD, FACC

Physician - Director of Cardiac Imaging

Daniel Karlsberg, MD


Sheila Chen, MD


Bonnie Richards, DO

Medical Director - Princeton, NJ

Michael B. Schwartz, DO

Physician - Shelton, CT


Alexa Essenfeld MS, RD


Stacey Milak, RDN

Registered Dietitian

Elli Kmiec, MBA, RDN, CDN


Barbara Bacal, RDN


Paige Heiden, MS, RDN


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Donna Hayek, RD


Exercise Physiologists

Dr. Harry Pino

Exercise Physiology Manager

Louis Degnan M.S, CPT, NSCA TSAC-F


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Isabella Burns, EP-C, BS, ACSM


Gianna Tapia, BS


CT Techs & Nurses

Darlene Chuva, RT (R, CT)

Senior Ct Technologist

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Denise Morano, BSN, RN

Clinical Manager

Nicole Grignoli RT (R, CT)


Clinical Staff

Jose Borja, BS

Medical Technologist

Victoria Wilcox, BS, RMA

Medical Assistant


Doug Cerminaro, MPA


Jillian Rhodes

NJ Office Manager

Milana Cantres


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Kristina DeGrandi

Office Manager CT

About David A Fein

Founder and Medical Director of the Princeton Longevity Center, Dr. David Fein has been a practicing physician with nearly 30 years of combined experience in Internal Medicine, Cardiovascular Diseases and Chronic Disease Prevention. He has traveled extensively to research the latest in medical advances, technology and wellness tools to incorporate into his nationally recognized preventive medicine center.

Dr. Fein is a Founding Member of the Society for Cardiovascular CT and remains one of the few Internists in the world that are Board Certified in Cardiac CT. He is an expert lecturer on topics such as Radiation Reduction Techniques and Coronary Artery Calcium Scoring in the clinical setting and has taught and certified hundreds of physicians to become proficient in the field of Cardiac CT.

He has also been invited nationally and internationally to speak at leading conferences on Preventive Medicine and lectures extensively on topics in preventive medicine, executive health, lifestyle management, and more. Additionally, Dr. Fein has been involved in developing health-related legislation in New Jersey.

A graduate of Franklin & Marshall College in Lancaster, PA, Dr. Fein received his medical degree from New York University School of Medicine and was elected to the Alpha Omega Alpha Medical Honor Society. Dr. Fein completed his residency training at Bellevue Hospital – New York University Medical Center and is Board Certified in Internal Medicine and Cardiac CT.

About John Rumberger

Dr. Rumberger is recognized as one of the world’s leading authorities on cardiac and vascular imaging using CT Scanning. His notable credentials make him uniquely qualified to provide interpretation of Coronary CT Angiography.

Dr. Rumberger has been Professor of Medicine and Consultant in the Department of Cardiovascular Diseases at the Mayo Clinic in Rochester, Minnesota. It was during this time that his reputation as a leader in the development and application of computed tomography of the heart was established. He has published extensively and continues to lecture and train other physicians in the United States, Europe, and Asia.

Dr. Rumberger received his doctorate in engineering from The Ohio State University in 1976 and graduated from the University Of Miami School Of Medicine in 1978. He completed his internship and residency in internal medicine at The Ohio State University Hospitals, and completed a cardiovascular diseases fellowship and early faculty development at the University of Iowa. Dr. Rumberger is currently Director of Cardiac Imaging and Lipid Management at PLC and is Board Certified in Internal Medicine and Cardiovascular Diseases.

During his over 25 year career as a clinician, educator, and researcher, Dr. Rumberger has published nearly 500 scientific papers and book chapters. He has lectured worldwide on Cardiac CT, early disease diagnosis, and wellness. He is an Established Investigator of the American Heart Association and a Founding Member of the International Society of Atherosclerosis Imaging. Dr Rumberger is an active Reviewer for the Journal of the American Medical Association, Archives of Internal Medicine, publications of both the American Heart Association and American College of Cardiology, and the New England Journal of Medicine.

About Daniel Karlsberg

Dr. Karlsberg is board certified by the American Board of Internal Medicine (ABIM) in both internal medicine and cardiovascular disease. Additionally, he holds board certifications in comprehensive echocardiography, nuclear cardiology, and cardiovascular CT. He is currently on the clinical faculty at NYU Langone Health in the Department of Medicine & Division of Cardiology.

Daniel Karlsberg graduated from the University of California and received his doctorate with honors from Sackler School of Medicine, Tel Aviv University. He then completed residency in internal medicine at the University of Colorado, followed by fellowship in cardiology at California Pacific Medical Center in San Francisco.

Dr. Karlsberg is a fellow of the American College of Cardiology and an active member of the American Society of Preventive Cardiology. As a preventive medicine physician, he has a special interest in the early diagnosis and management of cardiovascular disease, complex lipid disorders, and advanced cardiovascular imaging. Throughout his medical training and career, Dr. Karlsberg has been deeply involved in cardiovascular CT research and currently advises and teaches with the Society of Cardiovascular Computed Tomography (SCCT). Dr. Karlsberg maintains ongoing clinical research with both the Cardiovascular Research Foundation and The Lundquist Institute & Harbor-UCLA Medical Center.

Dr. Karlsberg is deeply passionate and enthusiastic about the intersection of healthcare and technology to empower and educate for better outcomes. He is honored to be part of the team at Princeton Longevity Center as Associate Medical Director where he maintains a practice that strives to improve health via prevention, early detection, and exceptional follow up. His sole goal is to work with you to create optimal health and wellness that are tailored to your needs.

About Sheila Chen

Dr. Chen is board certified in Internal Medicine. She did her undergraduate training at MIT. She attended St. George’s University School of Medicine and completed her internship and residency at St. Barnabas Medical Center in Livingston, NJ. She has been in practice for over 10 years, and in addition to providing quality preventive care at Princeton Longevity Center, she is the founder of Dimensions Direct Primary Care.

Dr Chen’s focus is to provide quality care at all stages of life. In addition to her role in primary care, she also serves as medical director of Heartland Hospice in Northern Virginia.

For Dr. Chen, medicine is not only a career, but a passion. She believes in a personalized approach, and strives to be the kind of physician patients can feel comfortable talking to. She is committed to providing the highest quality of care and treatment to her patients, and places special emphasis on overall health and wellness, preventive care and patient education.

About Bonnie Richards

Dr. Richards is a board-certified Family Medicine physician. She completed her undergraduate training at the University of Delaware where she earned a Bachelor of Science in Nursing. After working as an ER nurse for several years, she attended the New York College of Osteopathic Medicine to obtain her medical degree. She then completed both her internship and residency at Thomas Jefferson Family Medicine Residency program (formerly Aria Health) in Philadelphia, where she also served as Chief Resident in her final year.

Dr. Richards is a member of the American College of Osteopathic Family Physicians and the American Osteopathic Association. She strives to stay updated on current best medical practices to provide her patients with the highest level of medical care. She enjoys taking the time to talk with patients to fully understand how their health is impacted by their unique situations. She places a strong emphasis on preventative health care and addressing lifestyle changes that can improve overall health in addition to medical treatments. Her main objective with each visit is to help provide patients with the education and tools that they need to achieve their goals and live healthful lives.

About Michael B. Schwartz

Dr. Schwartz received his BS in Cardiorespiratory science from The State University of New York/Stony Brook in 1986 and graduated from the New York College of Osteopathic Medicine in 1990. He completed his internship and residency in Internal Medicine at the Yale University School of Medicine/Norwalk Hospital Program in 1994. He is Board certified in Internal Medicine by the ABIM.

Dr. Schwartz has received the ‘Patient’s Choice Award’ every year since 2008 as well as the ‘Most Compassionate Doctor Award’ every year since 2010. Most recently, he was awarded the America’s Most Honored Doctors – Top 10%, and was named one of Fairfield County’s “Top Doctors” by Moffly Media both in 2022.

Dr. Schwartz emphasizes preventative care to insure that his patient’s health is the primary focus of a comprehensive health care program.

Dr. Schwartz is accomplished in sports medicine and acts as the Chief Ringside Physician for Professional Boxing and Mixed Martial Arts (MMA) for the State of Connecticut as well as at the Mohegan Sun Casino and at the Foxwoods Resort Casino. Dr. Schwartz has written many publications on fighter safety and has testified in front of congress to promote safety in these sports. In 2011, as a testimony to his commitment to improving the safety and health of the professional boxer, Dr. Schwartz was inducted into the Connecticut Boxing Hall of Fame.

About Alexa Essenfeld

Alexa Essenfeld is a Registered Dietitian with years of experience educating and encouraging others about the importance of nutrition and wellness. Alexa graduated from Rutgers University with a degree in dietetics and then went on to pursue her masters and dietetic internship at the College of Saint Elizabeth.

Prior to coming to PLC, Alexa was the campus dietitian at a local university where she helped manage the dietary needs of those with food allergies. While at the university, Alexa also created unique vegan, gluten free and allergen free menus for the entire campus. Alexa also has experience counseling professional and Division 1 athletes on adopting sports performance diets. When working with clients, Alexa takes time to understand individual barriers and helps people discover how they can make improvements (big or small) to become the healthier person they aspire to be. Alexa has been affiliated with the Academy of Nutrition and Dietetics and the NJ Academy of Nutrition and Dietetics for over 8 years.

About Elli Kmiec

Elli Kmiec is a Registered Dietitian at Princeton Longevity Center’s Flagship office in Downtown Manhattan. She is a graduate from West Chester University of Pennsylvania with a Bachelor of Science in Nutrition and Dietetics degree with a concentration in Sports Nutrition. She was a research assistant in several studies, investigating proper fueling methods on the body composition of Division II NCAA athletes during her time at West Chester University of Pennsylvania. She is also earned her Master of Business Administration degree with a concentration in Entrepreneurship and Health Care Management from Dominican University while simultaneously completing her dietetic supervised practice hours across the Greater Chicago region.

Prior to joining PLC, Elli was an inpatient acute care Dietitian in Brooklyn, NY. She also started her sports dietetic practice experience as an RD with Tone House in Manhattan, NY working towards the Board-Certified Specialist in Sports Dietetics certification. Through education and professional practice Elli has gained experience counseling professional and collegiate athletes, as well as those with disordered eating patterns, and those with various chronic conditions like cardiovascular disease, diabetes, and kidney disease.

Elli’s nutrition areas of interest include cardiovascular health, mindful-based eating practices, and the brain-gut connection. Her professional goal as a Registered Dietitian is to aide our nation’s service members and veteran’s in making healthier lifestyle choices while transitioning to retirement in order to prevent early onset of cardiovascular disease.

About Barbara Bacal

Barbara Bacal is a Registered Dietitian with over 25 years of experience. She is a graduate of the University of Connecticut with a Bachelor of Science degree in Dietetics.

Prior to joining Princeton Longevity Center, Barbara worked for many years as a Clinical Dietitian at the Milford Campus of Bridgeport Hospital, assessing and instructing patients with a wide variety of medical conditions including heart disease, diabetes, and cancer. She has also worked in a medically-supervised weight loss office where she coached individuals through weight loss programs.

Barbara has taught weight loss classes on a military base and has conducted a 16 week course for people with pre-diabetes looking to prevent developing diabetes. Through community outreach programs, she has educated groups ranging from elementary school children to senior citizens about nutrition and health. Barbara has provided her expertise at health fairs and is on the Board of the Orange Visiting Nurse Association as a consultant dietitian.

Barbara loves to help people learn more about food and good nutrition. Her philosophy is that there is no such thing as a one size fits all, or “best”, diet. She focuses her instruction on each individual’s specific needs, using this information to create a meal plan tailored to their lifestyle. Her goal is to help each patient feel their best.

In her free time, Barbara is an avid baker who loves to experiment with new recipes and ingredients. She often uses her fellow PLC colleagues as tasters for her confectionary creations! When she’s not focusing on nutrition, you will find Barbara either on a spin bike or in the studio welding metal sculptures.

About Paige Heiden

Paige Heiden is our Registered Dietitian in New York City. She is a graduate of the University of Delaware with a Bachelor of Science in Nutrition and Dietetics. During her undergraduate career, Paige was a research assistant in several studies, investigating obesity in the pediatric population. Paige also earned her Master of Science in Clinical Nutrition from Rutgers University where she completed their Entry Level Master of Science in Clinical Nutrition (ELMSCN) program. Paige completed her dietetic supervised practice hours at several locations in New Jersey, including Cooperman Barnabas Medical Center, Kessler Rehabilitation and Rutgers Athletics.

Prior to joining PLC, Paige was an inpatient and outpatient Dietitian in Livingston, NJ. Paige covered all units of her inpatient facility including, but not limited to, pediatric and adult intensive care, transplant and burn units. Paige’s outpatient work took place at neurology, cardiology and weight management offices in Livingston and West Orange, NJ. Paige has also worked in the private practice space since 2021, with focuses on weight management and disordered eating. Paige loves helping her patients and clients learn the science behind nutrition, improve their relationships with food and reach their goals.

Through education and professional practice, Paige has gained experience in counseling patients across the lifespan with various chronic conditions including, but not limited to, cardiovascular disease, obesity, epilepsy and diabetes. Paige’s specific nutrition areas of interest include cardiovascular health and sustainable weight management through flexible dieting.

About Donna Hayek

Donna Hayek, RD brings over 20 years of experience as a registered dietitian to our Princeton office.

Prior to joining Princeton Longevity Center, Donna worked in various hospitals, long-term care facilities, gyms, and clinics. She received her BS in Food & Nutrition and Certificate in Sports Nutrition & Wellness from The College of St. Elizabeth in nearby Morristown, NJ. Donna is also certified as an Exercise Physiologist through the American College of Sports Medicine (ACSM.)

Throughout her career, Donna has worked with a wide range of patients, including pediatric, obstetric, adult, and elderly. In her spare time, she enjoys working out, shopping, and spending time with her puppy.

About Harry Pino

Dr. Pino joins Princeton Longevity Center as the Manager for Exercise Physiology and is board certified in Exercise Physiology with the American Society of Exercise Physiology and the American College of Sports Medicine. As a graduate of Indiana and Pacific Western University with post graduate training at Florida Hospital, Dr. Pino is also the founder of the sports performance lab VO2max Medical, LLC and is an adjunct assistant clinical professor at Tufts University, School of Medicine.

Dr. Pino is regarded as one of the leading authorities on sports performance testing, health and fitness and healthy weight loss in the United States. He is has consulted for both the Puerto Rican and Japanese Olympic Team and is the immediate past president for the Massachusetts Association of Clinical Exercise Physiologists. Dr. Pino is a former Director of the Clinical Exercise Physiology Program at Tufts Medical Center and has also served as the Senior Clinical Exercise Physiologist for the Center for Musculoskeletal Care Sports Performance Center at NYU Medical Center Langone, as the Medical Director for the Center for Preventive Medicine in NYC, as a Consultant for Next Level Physio Sports Performance and Physical Therapy Center, as a Clinical Integration Director for Celebration Health at Florida Hospital, and as a member on the Board of Directors for the Greater New York American College of Sports Medicine Chapter.

In addition to these accomplishments, Dr. Pino’s work has been featured on The Today Show, Good Morning America, PBS, CBS and CNN and in a variety of print media including the New York Times, New York Times Magazine, LA Times, Wall Street Journal, Shape, Men’s Health and more. Dr. Pino contributes to Sirius XM Doctor Radio and lectures on topics including exercise prescription for sports performance and chronic diseases. He was named one of the 100 Most Influential People in Central Florida for his work at the Rippe Health Assessment at Celebration.

About Louis Degnan

Louis Degnan, M.S., is a National Strength & Conditioning Association Certified Personal Trainer and a National Strength & Conditioning Association Tactical Strength & Conditioning Facilitator

Prior to joining The Princeton Longevity Center, Louis was a Wellness Coordinator at a United Methodist Homes in his hometown of Wilkes-Barre, Pennsylvania. He also worked as a Personal Trainer, EKG/Telemetry Technician, and Physical Therapy Aide both during and upon completion of his graduate coursework.

Louis received his Bachelor’s from East Stroudsburg University and his Master’s Degree from Bloomsburg University, both in Exercise Science. With his education and experience, Louis’ career goal is to make himself and expert in preventive medicine throughout the lifespan. Louis has experience in working with adults of all ages and recreationally active populations in physical therapy clinics, hospitals, commercial gyms, and group settings.

In his spare time, Louis is a self-proclaimed “comic book nerd”. He attends various comic book conventions annually and passionately incorporates healthy lifestyle and fitness habits to look the super-hero part in costume.

About Gianna Tapia

Gianna graduated from TCNJ with a B.S. in Health and Exercise Science. She has experience with different populations and trained people on how to achieve muscular strength and mobility that is best suited for them. Gianna has experience as a physical therapist/ chiropractic aide, as well as an intern at Health Quest Fitness Center. She participated and helped coach an metabolic/ strength training class, aqua aerobics class for older women and designed a wellness screening assessment for oncoming new clients to understand where there may be discrepancies in their biomechanics. Gianna has a certificate in assisted stretching and proprioceptive neuromuscular facilitation. In her free time, she loves to travel, try new foods, listen to podcasts, and dedicate one day a week on self-care!

About Denise Morano

Denise is originally from Staten Island, NY. She received her nursing degree at the College of Staten Island. Denise started her 35-year healthcare career as a certified nursing assistant. During that job, she realized how much she liked caring for and interacting with patients, as well as assisting them in their healthcare journey and helping them make changes towards a healthier lifestyle. She has critical care, assisted living, and long-term care nursing experience as a staff nurse, director of nursing, and administrator. Denise is also a certified yoga instructor and enjoys spending time with her husband, and twin boys in Manalapan.