Our Team
Sung H. Chun, MD
Dr. Chun went to Stanford University for undergraduate studies and went to the George Washington School of Medicine. He did his cardiovascular and cardiac electrophysiology fellowship training at Stanford. He was a faculty member at Stanford School of Medicine and served as the director of cardiac electrophysiology fellowship training program before joining PAMF. He has extensive research experience in basic science, animal studies, and clinical studies, especially in atrial fibrillation management. Combining this experience along with 30 years of treating patients with different rhythm disorders, he strives to deliver exceptional patient care. In addition, because rhythm disorder is often intertwined with other aspects of health and lifestyle, he approaches each rhythm disorder patient in a comprehensive manner, considering other psychological and physical influences.
Dr. Chun has been involved with medical missions to various countries for over ten years and serves as a board member for a non-profit organization focusing on medical missions and disaster relief.
Dr. Chun loves dogs, has a talking parrot that’s been with him for 27 years, loves driving, and has been trying to learn golf for over twenty years. He is fluent in English and Korean.
Shaun Cho, MD
Dr Cho is a cardiac specialist treating cardiac rhythm disorders, performing a variety of ablation procedures (including atrial fibrillation, atrial flutter, SVT ablations) as well as device implantation and management including pacemakers, defibrillators and cardiac resynchronization devices.
Dr. Cho received his medical degree from Cornell Medical College and his medical residency at the Hospital of the University of Pennsylvania. He completed his cardiology and cardiac electrophysiology fellowship training at Stanford Medical Center. He has practiced at Palo Alto Medical Foundation since 2010, and sees patients at both the Palo Alto and Mountain View Centers. He serves as the Cardiac Electrophysiology Medical Director at El Camino Hospital.
EunJeong Kim, MD
Dr. Eunjeong Kim is a cardiologist and electrophysiologist who specializes in diagnosing and treating arrhythmias. She has expertise in treating a variety of heart rhythm disorders such as atrial fibrillation, atrial flutter, supraventricular, and ventricular arrhythmias with antiarrhythmic medications and catheter ablations. She is also skilled in complex management of cardiac pacemakers and defibrillators including subcutaneous defibrillators, cardiac resynchronization therapy, physiologic pacing, and leadless pacemakers.
Dr. Kim earned an undergrad degree at Washington University in St. Louis, Missouri. She received a medical degree and completed a residency in Internal Medicine at Boston University School of Medicine. After working as a hospitalist and teaching medical students and residents at Massachusetts General Hospital in Boston, she pursued further training in cardiology fellowship at Vanderbilt University Medical Center in Nashville, TN. Then, she moved to San Francisco for her family and completed cardiac electrophysiology fellowship at UCSF.
Dr. Kim is looking forward to building a lifelong relationship with her patients. She values the importance of shared decision-making and personalized treatment plans for individual patients. Outside work, she enjoys exploring the beautiful nature in California, playing keyboard, cooking, and traveling. Dr. Kim is fluent in English and Korean.
Girish Narayan, MD
Dr. Narayan is a compassionate heart specialist who believes that understanding your health is the first step to taking great care of it. He listens closely to your personal story and works with you to create a care plan that feels right for you.
With over 20 years of experience with ablation procedures, Dr. Narayan is an expert in treating conditions such as atrial fibrillation and caring for patients with pacemakers and defibrillators. His advanced training in cardiac MRI lets him use state-of-the-art imaging to guide complex heart care.
Dr. Narayan earned his MD from the Harvard Medical School, completed his Internal Medicine residency at Columbia Presbyterian Hospital, and specialized in cardiology and cardiac electrophysiology at Stanford. He is a proud Fellow of both the Heart Rhythm Society and the Society for Cardiovascular Magnetic Resonance.
Throughout his career, he has served as chief clinical advisor to several companies to develop several innovative cardiac devices now in everyday clinical use. Today, he serves as the Executive Medical Director of the Cardiovascular Service Line for the Palo Alto Medical Foundation Group, where he leads efforts to improve patient care and outcomes. He also founded the Cardiac Prevention Program at Encina Cardiology , underscoring his passion for proactive heart health.
When he’s not caring for patients, Dr. Narayan loves spending time with his family, painting, playing with his dog Milo, and watching his kids compete in volleyball. His warm, personal approach and deep expertise make him a trusted partner in your journey toward better heart health.
Michelle Gould, NP
Michelle Gould is a nurse practitioner specializing in cardiac devices and arrhythmias.
Michelle grew up in New England, received her Bachelor’s Degree from Saint Anselm College and her Master’s Degree from UCSF. She worked at Stanford for ten years in cardiology before coming to Palo Alto Medical Foundation over twenty years ago. When she isn’t at El Camino Hospital or Palo Alto Medical Foundation, she enjoys snowboarding, swimming, trail running, playing ice hockey and spending time with her family.
Cristina Cuellar, B.S., RT(R)(CI) Manager, Cardiology & Nephrology
Cristina Cuellar is an accomplished healthcare leader with extensive clinical and operational expertise across Cardiology, Electrophysiology, Structural Heart, Interventional Radiology, and Echocardiography. With a proven track record of driving innovation, Cristina has successfully led high-performing cardiovascular teams and spearheaded the development of advanced cardiac programs, including Electrophysiology, Structural Heart, and Mechanical device systems.
Her leadership has been instrumental in implementing system-wide improvements such as CUPID and GE MAC LAB, enhancing both patient care and operational efficiency. Cristina also led a strategic expansion of echocardiography services, resulting in a nearly 300% increase in volume while maintaining top-tier national quality metrics in Cath PCI, A-Fib, and EPDI registries.
At Sutter Santa Rosa Regional Hospital, Cristina played a key role in launching the Electrophysiology and Structural Heart Programs, reviving the NICU Echo program, and guiding staff through critical events such as wildfire evacuations and COVID-19 response efforts. Her commitment to excellence, innovation, and compassionate care continues to make a lasting impact on the communities she serves.
She currently serves as Manager for the Imaging, Cardiology and Nephrology departments in Palo Alto and San Carlos, where she oversees multidisciplinary teams and drives operational excellence.
Adrian Moreno, Surgery Scheduler
Adrian enjoys hiking, playing basketball and going to the movies. He also enjoys traveling and always tries to catch a live sporting event whenever he’s in a new place. Adrian has been with Palo Alto Medical Foundation since 2021 and has a previous background in nutritional science and sales.
Isabelle Barlaan, Project Coordinator
Isabelle Barlaan earned her Bachelor of Science in Health Science, where she focused on research in healthcare. During her studies, she volunteered at RotaCare Marin as a medical scribe and at Marin General Hospital in the ICU on weekends, gaining firsthand experience in patient care. She later interned at Seton Medical Center with an Internal Medicine practitioner and with a physician assistant at UCSF’s Cardiothoracic ICU and step-down unit. Before joining PAMF, Isabelle worked at Invitae, a genetic testing company, where she was part of the data processing team and collaborated closely with both the accessioning and client services departments.
In her current role as Project Coordinator at the Arrhythmia Center, Isabelle serves as a liaison for the physicians and team, ensuring effective communication and smooth coordination across projects. She helps oversee clinic initiatives and collaborates with the PAMF Research Institute to support innovative ideas and ensure successful project execution. Isabelle believes that exceptional patient care begins with a strong, cohesive team, and she strives to foster that unity in her daily work.
Outside of the clinic, Isabelle leads an active lifestyle and enjoys spending time at the gym. She’s currently training with the goal of competing in a bodybuilding competition in the near future.
Sarah Contreras, RN New Patient Coordinator
Sarah is a registered nurse with experience in healthcare for over ten years. Degrees and certifications include a Bachelor of Science in Nursing, Associate Degree in Nursing, licensed California RN, licensed California Public Health RN, Board-Certified Cardiovascular RN, Certified Progressive Critical Care Nurse. Her career began volunteering and assisting with research in a post-acute setting in high school. This progressed into experiences in social services, skilled nursing, post-acute care, long term acute care, acute care, trauma/neuroscience, progressive critical care, and ancillary teaching at her alma mater of Ohlone College before transitioning to outpatient cardiac care.
Sarah has worked through the continuum of care and believes in a holistic approach to health and creates care plans tailored to each individual. Her goal is to make patients and their loved ones feel knowledgeable and empowered as they begin a new health journey with our electrophysiology practice.
When not working, Sarah enjoys doing puzzles, knitting, and yoga in addition to spending time with her spouse and three cats.
Gloria Medina, New Patient Navigator
Gloria Medina has worked in cardiology for eight years as a dedicated medical assistant, providing compassionate care and support to patients. She is deeply committed to helping others and takes pride in her role within the medical field. Outside of work, Gloria loves spending quality time with her family, and going on outdoor runs. Her warm personality and active lifestyle reflect her passion for both health and happiness.
Leslie Lukash, RN
Leslie is a registered nurse with over 30 years of experience caring for patients in many roles, in both inpatient and outpatient settings. As a member of the team, her focus is on guiding, educating and supporting patients through their healthcare journey. When not at work, Leslie enjoys spending time with her family, traveling, taking walks and reading.
Jamie Lajara, RN
Jamie is a registered nurse with a Bachelor of Science in Nursing (BSN) from San Jose State University, earned in 2018. She has been with Palo Alto Medical Foundation since 2007 and joined the cardiology dept in 2013. She brings extensive experience and a strong commitment to patient centered cardiovascular care.
Caroline Milford, RN
Caroline is a registered nurse originally from the East Coast. She completed her undergraduate nursing degree at Saint Louis University and earned her master’s in nursing at the University of Missouri. She came out to the Bay Area originally as a travel nurse and has enjoyed building her career here.