Andrew C. Ahn, MD, MPH

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Home Institution: Beth Israel Deaconess Medical Center, Massachusetts General Hospital

Field: Computational Medicine

Current Positions:

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    Assistant Professor of Radiology, Harvard Medical School 
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    Hospitalist, Department of Medicine, Beth Israel Deaconess Medical Center 
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    Assistant in Neuroscience, Department of Radiology, Massachusetts General Hospital

Can computational analyses of biomedical signals—such as heart rate and blood pressure—lead to personalized treatments and better understanding of human health?

Fellow Project

Despite substantial advances in diagnostic tools and therapeutics, modern biomedicine continues to struggle with defining terms such as “health” and “wellness”—concepts connoting a holistic characteristic that cannot be readily quantified or measured.

The challenge originates from the simple fact that measurable, meaningful variables become increasingly difficult to identify as the perspective is broadened toward the system as a whole. With advances in complexity and systems-based sciences, however, we are auspiciously poised to overcome these challenges and to use complexity-derived, objective measures that capture the overall state of human health in a way not previously deemed possible. 

Although promising in principle,  systems-based medicine in practice  is attached with many unanswered questions: How should these systems-level measures be reliably derived in a clinical setting? Which measures are most informative about one’s clinical condition? How should the results be interpreted and be related to other more conventional parameters? And can they be practically implemented to generate meaningful improvements in clinical care?

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To identify possible answers to these questions, Dr. Ahn is employing a large, intensive care database called the MIMIC II (Multiparameter Intelligent Monitoring in Intensive Care) Database to investigate the utility of systems-level measures in clinical care. This database is ideal because of its size (N=23,000), incorporation of continuous waveforms (N=4,800 with EKG, arterial pressures, respiration, and plethysmography), comprehensiveness (demographics, vitals, lab tests, medications, care notes, and imaging reports), and diversity (data from medical, cardiac, and surgical units).

These analyses will provide not only the preliminary data on the usefulness of systems-approach to the ICU setting, but also the necessary framework to deal with large, complex databases such as MIMIC II, which contains heterogeneous population with varying clinical conditions, stages of disease, ICU settings, and provide teams.


 

Biography

Dr. Ahn is a junior faculty member of both the Massachusetts General Hospital Martinos Center and the Beth Israel Deaconess Medical Center Division of General Medicine and Primary Care, as a hospitalist in the Hospital Medicine Program. He dedicates half his time to research while spending the remaining one-half time to clinical work. His research interest is in computational medicine and in large-scale electrophysiological process within the human body. These interests stemmed from his initial interests in acupuncture.

In 2002, Dr. Ahn joined the three-year combined General Medicine and Complementary Alternative Medicine Fellowship at Harvard Medical School directed by Dr. Russell Phillips. As part of this fellowship, he became credentialed in acupuncture by completing a 300-hour acupuncture course for physicians at Harvard Medical School. He also earned a Master in Public Health degree at the Harvard School of Public Health with a concentration in Clinical Effectiveness. 

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Much of Dr. Ahn's fellowship was focused on studying the mechanisms underlying acupuncture treatments. During the fellowship, he evaluated the mechanistic significance of the elusive “acupuncture meridian” by working with Dr. Helene Langevin, a well-established acupuncture and connective tissue researcher at the University of Vermont. They measured the electrical impedance along connective tissue planes associated with meridians compared to parallel control muscle tissue. They found that electrical impedance along the pericardium meridian was significantly lower compared to controls.

To further elaborate the electrical properties of meridian-associated connective tissue, he applied for and received a five-year NIH K23 career development award. This award provided support for pilot research projects, mentorship, and coursework, and it took place at Harvard Medical School, Beth Israel Deaconess Medical Center and MIT. His mentors were Ted Kaptchuk, Helene Langevin, Alan Grodzinsky, and Russell Phillips, who collectively provided expertise in Asian medicine, acupuncture, connective tissue, bioengineering and clinical research.

Dr. Ahn also joined the MIT Advanced Study Fellowship, through which he took graduate courses in physics and engineering and completed coursework equivalent to those required for a PhD in biological engineering. During this time, he published a systematic review on the electrical properties of acupuncture points and meridians and a review on the relevance of collagen piezoelectricity in bone deposition.

He also published a study showing that electrodermal measurements at acupuncture points may be associated with clinical measure in women with chronic pelvic pain. In addition, he collaborated with various engineering and physics experts to study the electrical potential and impedance of loose connective tissue using state-of-the-art devices such as bio-Kelvin probe, impedance gain phase analyzer, and biopotential amplifiers.

Due to these early interests in bioelectricity, his research interests have evolved towards investigating large-scale bioelectrical effects within the human body that may play important physiological roles: specifically, the importance of electrical properties of fibrillar collagen in musculoskeletal physiology, the role of streaming potential and electroosmosis in fluid/circulatory regulation, and the influence of large scale electrical potential gradients on nerve activity.

In March 2010, he joined the MGH Martinos Center for Biomedical Imaging where he has access to a state-of-the-art high-frequency VisualSonics ultrasound to collaborate with
Dr. Vitaly Napadow to further evaluate these large-scale electrophysiological processes and to study neurological mechanisms of acupuncture.

Dr. Ahn has also developed an interest in applying systems/complexity theory to medicine and has written about the applications of complexity/systems theory to clinical practice. He published a widely-cited two-part series in PLOS Medicine discussing the limitations of reductionism in medicine and exploring the role for a systems approach in clinical medicine. He also co-authored a NIH-NCCAM sponsored position paper on the applications of complexity theory to CAM research.

Education & Training

Fellowship, General Medicine/CAM, Harvard Medical School

Graduate Courses, Biological Engineering, MIT

MPH, Clinical Effectiveness, Harvard School of Public Health

Residency, Internal Medicine, University of Michigan Medical Center

MD, New York University

BA, Biophysics, University of California Berkeley


 

Selected Honors

Patient-Oriented Career Development Award (K23), National Center for Complementary and Alternative Medicine


 

Selected Publications 

Electrical impedance along connective tissue planes associated with acupuncture meridians.
BMC Complementary and Alternative Medicine, May 2005 

The limits of reductionism in medicine: could systems biology offer an alternative?
PLOS Medicine, May 2006

The clinical applications of a systems approach.
PLOS Medicine, May 2006

Electrical characterization of acupuncture points: technical issues and challenges.
Journal of Alternative and Complementary Medicine November 2007

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