Ki H. Chon, PhD

Krenicki Professor

Biomedical Engineering Department

---

Research Overview

My recent research work is focused on the development of wireless, wearable, and low-cost monitoring devices for detection of cardiac malignant arrhythmias. In particular my lab has recently developed a smartphone application for atrial fibrillation (AF) detection without any external electrocardiogram hardware. We are able to accurately detect AF by applying our patented signal processing algorithms on fingertip pulsatile signals which are derived from the smartphone camera. A grant application on this work to NIH has received a perfect impact score of 10, and will be funded ($400K). In addition, we can use the pulsatile signals from the fingertip to extract heart rate, respiratory rate, oxygen saturation and autonomic nervous function which we have recently shown can be used to detect the onset and progression of cardiovascular diabetic autonomic neuropathy. Extending our approach to extracting the aforementioned vital signs from a smartphone, we are also working on developing a wearable and wireless pulse oximeter sensor for early diagnosis and quantification of hypovolemia at levels of blood loss earlier than can be identified by changes in vital signs or physician estimation. This area of work was recently funded ($1.9M) by the Department of the Army for 3 years.

I am also currently funded by a three year grant ($614K) from the Office of Naval Research for early detection of decompression sickness. We have shown that our patent-pending algorithm is effective in separating the dynamics of the sympathetic and parasympathetic nervous systems from heart rate fluctuations. Using our algorithm we have recently shown significant depression of the ANS dynamics in both neurological (injures of the spinal cord) and non-neurological (cardiopulmonary) decompression sickness (DCS) in swine. More importantly, we are able to predict the onset of non-neurological DCS approximately 30 minutes prior to trained human observers. Further validation and eventual extension of our DCS detection to humans is needed in order to help Navy divers cope with or prevent DCS. To implement this capability, however, a hydrophobic ECG electrode that is functional in a fully submersed and salt-water environment must be developed. Towards the goal of developing such an electrode, we have recently successfully developed prototypes using carbon black powder and polydimethylsiloxane (PDMS). A patent on this technology has been filed by our institution. Our carbon-based electrodes are able to provide all morphological waves (PQRST) of ECG signals in both dry and wet environments. Further, in dry environments, unlike most ECG electrodes, our carbon-based electrodes do not require wetting of the electrodes to function properly. This means that they do not require hydrogel, and thus do not expire or dry out. Our carbon electrodes are re-usable, flexible and appear not to degrade with repeated usage, hence, they could maybe be incorporated directly into a wetsuit so that vital sign information can be obtained without replacing electrodes for repetitive dive scenarios. We have received a two-year grant ($330K) from the Office of Naval Research for further development and testing of hydrophobic electrodes for Navy divers.

Education

University of Connecticut B.Sc. 1981-1986 Electrical Engineering

University of Iowa M.S. 1987-1988 Biomedical Engineering

University of Southern California M.S. 1989-1991 Electrical Engineering

University of Southern California Ph.D. 1989-1993 Biomedical Engineering

Massachusetts Institute of Technology Post-doc 1994-1997 Cardiovas Physiology

Recent/Selected Publications

Google Scholar