Principal Investigator


Igor R. Efimov, Ph.D.
The Lucy & Stanley Lopata Distinguished Professor of Biomedical Engineering, Cell Biology and Physiology, and Radiology at Washington University in St. Louis. Our NIH-funded research laboratory studies the biophysical mechanisms of cardiac conduction and arrhythmia, and has developed novel anti-arrhythmia therapies, including low-energy defibrillation therapy. The lab works on future treatments for the heart rhythm disorders and on engineering the pacemaker and conduction system of the heart, using electrical engineering, molecular biology, and multimodal imaging techniques. Dr Efimov co-founded a company, Cardialen, Inc. in 2008. The company goal is to develop pain-free cardioversion therapy, with a primary focus on atrial fibrillation. It is commercializing WU technology to develop implantable low-energy (low voltage) pain-free atrial cardioverters. Dr. Efimov serves as a Director, Chief Scientific Advisor and Chair of the Cardialen Scientific Advisory Board. Bio: Ph.D. from Moscow Institute of Physics and Technology (1992), Postdoc (1992-1994) University of Pittsburgh, Faculty Appointments at the Cleveland Clinic (1994-2000), Case Western Reserve University (2000-2004), Washington University in St. Louis (2004-present)
Bas Boukens, Ph.D.
I am a research scientist interested in the relation between cardiac molecular biology and electrophysiology. The main goal of my research is to understand the molecular mechanism underlying electrophysiological remodeling during disease.
Megan Flake
I am the laboratory manager in the Efimov Lab. I am involved in assisting with the daily operation of our lab, training and supervising undergraduate and graduate students, managing ordering and supplies, and molecular biology experiments.
Graduate Students

Matt Sulkin
I am currently a 5th year graduate student and graduated from the University of Rochester in 2008. My research is focused on developing new tools for studying cardiac metabolism in the whole heart. I am interested in the role of cardiac mitochondria and metabolic substrates in the genesis of arrhythmias. Link to Open Source 3D Printing Technology:
Katherine Holzem
I am a graduate student in the Washington University MD/PhD program and am currently pursuing my PhD in biomedical engineering. I am very interested in understanding the mechanisms of arrhythmogenesis in human heart failure, so I participate in the collection and analysis of human heart tissue in the Efimov lab.
Sarah Gutbrod
I am a fourth year graduate student focusing on improving the way we study the spatiotemporal dynamics of atrial and ventricular arrhythmias and applying this to understanding the biophysical mechanisms of novel anti-arrhythmia strategies.
Chris Gloschat
I am a third year graduate student and will be spend my fall rotation working on refining a wireless mouse pacemaker design. I received my B.S. in Biomedical Engineering from the University of Utah.
Chaoyi Kang
I am a third year PhD student. My research focuses on investigating cardiac mechanics such as Excitation-Contraction coupling, Mechano-Electrical feedback, and pharmacological/mechanical stress induced remodeling using novel fluorescent imaging systems. I received my bachelors from University of California, Davis in 2011.
Undergraduate Students
Connie Shao
I am currently a fourth year undergraduate student majoring in Biomedical Engineering. My research focuses on creating a miniature implantable mouse pacemaker. 
Megan Tetlow
I am currently a fourth year undergraduate student studying Biomedical and Electrical Engineering. I am working on creating a system to control our experimental setup in LabVIEW and designing a new tissue chamber.
Joseph Marmerstein
I am a second year undergraduate student majoring in Biomedical Engineering. My research focuses primarily on the obesity paradox in heart failure, and the possible mechanism for arrhythmogenesis. My work includes histological analysis of mouse hearts and analysis of in-vivo mouse electrocardiograms.
Eli Madden
I am a third year undergraduate student majoring in Anthropology. I investigate arrhythmogenesis in the transition from non-failing to failing human hearts with a focus on ion channel remodeling. Additionally I will be studying the obesity paradox as it relates to this remodeling. My work involves Western blot analysis of protein expression changes as well as mRNA RT-PCR analysis of gene expression changes.


Jacob Laughner
My main research focus was developing novel tools for systems physiology studies of heart failure. I worked on three projects in the lab: 1) a miniature pacemaker to create a pacing-induced model of heart failure in mice, 2) a combined structured light/optical mapping system for studies of excitation-contraction coupling, 3) a HIFU ablation and optical mapping system for treatment of atrial and ventricular arrhythmias.
Aili Cai, M.D.
I was the laboratory manager in the Efimov Lab for 3 years. My work was to assist with the daily operation of our lab, training and supervising undergraduate and graduate students, managing ordering and supplies, and routine electrophysiology and molecular biology experiments.


Christina Ambrosi, Ph.D.
My research focused on characterizing the atrial arrhythmogenic substrate in terms of both structural and molecular remodeling. More specifically, I explored the use of optical coherence tomography in identifying components of both canine and human hearts and used high-throughput gene expression analyses to explore the roles of age, gender, and disease on molecular electrophysiological targets in the human heart. Additionally, I developed and validated a technique for low voltage defibrillation in a rabbit model of atrial tachyarrhythmias. I received my BS/MS in Biomedical Engineering from Washington University in 2004. I subsequently worked for St. Jude Medical as a Technical Service Specialist in the Cardiac Rhythm Management Division and returned to Washington University in 2006 to pursue my PhD. After defending my PhD in August 2011, I will be a Postdoctoral Research Associate in the laboratory of Dr. Emilia Entcheva at Stony Brook University in New York.

Qing Lou, Ph.D.
My research focused on cardiac functional remodeling and its relation to arrhythmogenesis in a rabbit infarction model and failing human heart. I was involved in building two advanced optical imaging systems and the corresponding data analysis toolbox. Using the tools developed myself, I quantified the remodeling of conduction, repolarization, and excitation-contraction coupling, and explored the mechanisms of arrhythmias responsible for the sudden cardiac death in the heart failure patients.

Di Lang
My research focused on dysfunction of calcium related signaling pathway and proteins in cardiac pathophysioloy, especially in arrhythmogenesis. I also studied the effect of different type of beta adrenergic receptor agonist stimulation on end-stage heart failure and non-failing human hearts, which facilitated our understanding and development of the treatment for heart failure.
Wenwen Li, Ph.D.
I'm a fifth-year graduate student of Dr. Igor Efimov. My research focused on mechanisms of arrhythmias and low-voltage defibrillation of atrial and ventricular tachyarrhythmias. I worked with optical mapping system, electrode mapping system, defibrillator unit design, and large animal models like rabbits and dogs.

Deborah Janks, Ph.D.
Ph.D. from Oakland University in Medical Physics, 2006. Postdoc at Vermont School of Medicine, 2006 - 2008. Postdoc at Washington University from 2009 - present. I investigated the role of Purkinje fibers during ventricle fibrillation.
Ajit H. Janardhan, M.D., Ph.D.
Electrical cardioversion remains a widely used therapy for restoration of sinus rhythm in patients with atrial fibrillation. Meanwhile, Implantable Cardioverter Defibrillators (ICDs) have revolutionized the treatment of patients with advanced heart failure and victims of sudden cardiac arrest (SCA). Nonetheless, these therapies require large amounts of energy to successfully convert atrial fibrillation (AF) or ventricular tachyarrhythmias (VT and VF). As a result, these therapies are painful, make implantable devices and leads more prone to failure and significantly increase overall healthcare costs. Our laboratory has demonstrated that restoration of sinus rhythm from AF or VT can be achieved using low energy defibrillation strategies rather than traditional high energy shocks. These studies took place primarily in rabbit and more recently, in open chest canine models. My major interests are low energy defibrillation of AF and VT. First, I am developing, refining and testing low energy, multiple-stage defibrillation in a canine model of high rate pacing-induced AF using transvenous, implantable leads. Second, using a canine open chest acute myocardial infarction VT model, I am evaluating low energy, multiple-stage defibrillation therapies. We will translate this strategy to a closed chest canine VT model using implantable leads in the future. The eventual goal of these projects is to design and deliver low energy therapies for defibrillation of AF and VT through implantable devices in humans.

Vinod Ravikumar
I was an undergraduate student at Washington University majoring in Biomedical Engineering. My research focus in Efimov Lab was to investigate the properties and roles of various ion channels in the heart, specifically in the human ventricle. My previous work has revolved around the activity of Connexin 43 and N cadherin gap junction proteins and studying their inactivation and downregulation during heart failure. I also investigated similar ion channels to see if they exhibit similar characteristics across different animal species.


Xinyuan Sophia Cui
I graduated from Washington University in St. Louis in May 2012. During my time in Dr. Efimov's lab, I built and tested pacemaker for mice. Successfully halved the size of original Medtronic design and composed detailed technical user manual for the construction, utilization and alteration of the device. In addition, I assisted in creating a MATLAB graphical user interface (GUI) to translate raw optical mapping data into meaningful graphic representations. Dr. Efimov was also my mentor on my senior design project on the topic of implantable flexible and stretchable devices for cardiac therapy. My design group came up with a 3D model for a defibrillator composed of finger-like extensions that span from the apex to the base of the heart. The extensions contain sensing and stimulating electrodes to detect arrhythmias and locally defibrillate active foci, respectively. Currently, I am pursuing a PhD degree in biomedical engineering at the University of Virginia. My research focus is on cardiac imaging.

Olga Neyman
I was an undergraduate student majoring in Biomedical Engineering. I researched the conduction properties of the accessory pathway seen in dogs with Wolff-Parkinson-White syndrome and spent most of my time on histological studies related to this. I have also constructed 3D models of the heart that show the accessory pathway.
Colleen Rhoades
I was an undergraduate student at Washington University studying Biomedical Engineering. I researched the structure and function of Pky2 and Pannexin gap junction remodeling in the heart using molecular biology techniques to quantify their expression. Also, I helped with optical mapping and analyzing the resulting data with MatLab.

Xinpei Wang
I am a fourth-year Ph. D. student in Biomedical Engineering, and currently a visiting student in the Efimov lab. My research focus in Efimov lab is to build a platform for wireless electrophysiology monitoring and pacing.
Alexey Dvornikov, Ph.D.
I am a visitor from Russia, Nizhny Novgorod State University. My PhD thesis was focused on autonomic heart regulation. My current field of research is calcium dynamics in cardiac muscle. I am studying the force-frequency relationships and strongly interested in electro-mechanical coupling in the heart. Another research project includes the investigation of automaticity and heart rate variability during adrenergic and cholinergic stimulation of heart and modeling of SAN. Now, I am learning an optical mapping in the Efimov Lab to investigate heart arrhythmia mechanisms then.
Birce Onal
I graduated from Washington University in St. Louis in May 2012 with a Bachelor's in Biomedical Engineering and a minor in Computer Science. While I worked in Dr. Efimov's lab, I extracted mRNA samples from human heart tissue for statistical analysis of gene expression among male and female hearts. I also contributed to a continually evolving program and user manual for analyzing optical mapping data, and built a graphical user interface for sensitivity analysis of a cardiac action potential model. Dr. Efimov was my senior design mentor for my group's project, "A Portable Electrocardiographic Impedance Tomography Imaging Device." I am now at Ohio State University working towards a Ph.D in Biomedical Engineering with a focus on cardiac cell excitability.
Fu Siong Ng, M.D., Ph.D.
I was a Clinical Research Fellow at Washington University in St. Louis, and also a Clinical Lecturer in Cardiology and Clinical Cardiology Fellow at Imperial College London. I obtained my MD from the University of London and my PhD from Imperial College London. I am on a clinician scientist path and the focus of both my clinical work and research are in the field of cardiac electrophysiology. My research interests included investigating the determinants of ventricular arrhythmogenesis in a number of pathological settings, including acute ischemia, reperfusion and chronic post-myocardial infarction. I conducted functional studies investigating the electrophysiological changes in intact human myocardium during acute ischemia-reperfusion and gap junction uncoupling.
Hye Jin Hwang
I am a clinical electrophysiologist and visited Washington University for 1 year. Remarkable advances of diverse therapeutic modalities in fields of electrophysiology have been made over the past decade. Various arrhythmic diseases including Atrial Fibrillation, Paroxysmal Supraventricular Tachycardia, Ventricular Tachycardia and Ventricular Fibrillation are now treatable with catheter ablation or implantable devices, rather than pharmacological agents. Currently, our clinical electrophysiologists are making multiple ablation lines on the heart with new technology until the arrhythmia disappears. Aren’t we simultaneously creating substrate of another arrhythmia? The electrical shocks that devices deliver stop arrhythmias, yet simultaneously often bring unintended hazardous consequences, such as heart failure aggravation and increased mortality, in addition to infection. Ironically, our struggle to conquer arrhythmias often gives another new assignment to us. Our attempts to maximize omnipotent-like device/ablation technology are now threatening ourselves. What therapeutic strategy should we head to? One possible solution would be to head to the “minimization” strategy. Will minimal pacing (already tried), minimal ablation, minimal shock, invisible wire, and minimal device be new solution to release from our distress? My research focused on the relationship of sinus exit pathways and sinus node, and the new minimized treatment for sinus node-related diseases.