Discretizing a hybrid cardiac reconstruction: A novel simulation of sustained fibrillation

Summary

Acute cardiac arrhythmias are the main cause of death in industrialized countries; despite clinical importance, the mechanisms behind the onset and dynamics of cardiac arrhythmias are poorly understood. The purpose of this work is fivefold: (1) determine how smaller blood vessel radii affect the moving wavefront velocity, virtual electrode (VE) formation, and transmembrane potential induced by a shock, (2) elucidate a minimum radius correlative to shock strengths of interest, (3) computer engineer a hybrid remodel, (4) create a new cell model based on the hybrid’s new boundary condition, and (5) simulate chaotic spiral waves for the first-time in cardiac research. Through examining the role of small blood vessels, a minimum radius was identified at which a current will propagate, 100μm. The velocity of the moving wavefront remained constant and no VEs form in the blood vessel region for all blood vessels below the size of the minimum radius. Thus, ≤ 100μm blood vessels can be excluded in the first ever vascular mathematical model of the human heart at a feasible cost. A hybrid model was created, where the heterogeneities help depolarize a fibrillating heart for a faster and more successful defibrillation. Consequently, a cell model was coded to simulate fibrillation, and a .33V low energy shock defibrillated the induced arrhythmia. Futuristically, my cell model’s ability to simulate can be used in virtual reality surgery to calculate a personalized adjustment of conductivity in the human heart as an alternative to implementing a separate pacemaker, thus curing a faulty heart.

Question / Proposal

How can we end heart attack with a cheap and easy device?

How can a $9 shock-pen replace $3000 AED machines?

How can artifical intelligence be used to cure faulty hearts?

Research

Method / Testing and Redesign

Results

Conclusion

About me

Growing up, I envisioned inventing life-saving gizmos like mechatronic suits for the elderly and biofuel generators for leftover food. My ideas are still eccentric, but research has taught me to ground my seemingly outlandish innovations in experimentation.

As the first female President of my school’s top-ranked Math Team, I draw inspiration from how Iranian-born Maryam Mirzakhani broke the highest glass ceiling for women in mathematics when she became the first women to receive the Fields Medal.

Achieving a PhD in Biomechanical Engineering, I see myself as an inventor with patents, publications, “disruptive” manufactured devices, and involvement in a plethora of other multifaceted projects. I also hope that my Journal of Computational Biomechanics will have grown to attract an international base of authors as the prospect of universally sharing information to inspire and facilitate an experiment on the other side of the world excites me.

Winning the Google Science Fair would share my invention with the world—a prospect that’d bring tears to my eyes. The prizes are life-changing experiences, but nothing could surmount the feeling of gratification and elation of having Google support my innovation. I so dearly want my hard work to benefit society, and I want to expand our understanding of medicine to implement futuristic technologies like virtual reality surgery or bionic devices to cure impaired senses; winning Google Science Fair means a company as established as Google sees promise in my ability to benefit society through scientific discovery, and I can’t think of a prize better than that.

Health & Safety

As a purely computational project, no health and safety procedures were followed nor needed. 

Mentor: James Glimm
Office: Math Tower 1-121, Stony Brook University
Phone: 631-632-8355
Email: glimm@ams.sunysb.edu

Bibliography, references, and acknowledgements

Acknowledgements:
I received significant guidance from my high school Science Research teacher, Dr. Serena McCalla in the development of my ideas. Dr. McCalla has extensively encouraged me. She has provided insightful edits, challenged my conclusions, and spent countless hours with me commenting on aspects of my verbal presentation or written report. Through one-on-one meetings, we’ve discussed weaknesses of my project and brainstormed avenues of improvement. 

My mentor, Dr. James Glimm, encouraged me to read some journal articles on fluid dynamics, which he knew would fascinate me. Sure enough, I was entranced and began compiling a research binder and thorough literature review, which sparked many ideas that I was craving the chance to explore. Noticing my exuberance, Dr. Glimm said, “I’ll throw you in with the PhD students, and you’ll either sink or swim.” I was determined to swim.

First, I sought to code time-optimized atrial fibrillation code in CHASTE cardia to determine whether the current Mahajan model of the human heart well describes the experimentally documented behavior of the fluctuating transmembrane potential. Next, frustrated by the oversimplification of the Mahajan cardiac model, I yearned to incorporate the vascular dynamics into a much more realistic and useful MeshLab geometrical model. My novel approach required elucidating a minimum radius, where the presence of a blood vessel was too insignificant to perturb a wave-front’s propagation. I sought new heterogeneous cardiac elements to engineer—intracellular clefts, fiber orientation, scarring, and fatty tissue. As the quantification of infinite geometries elucidated a focused range, I was able to target my engineering goals and complete each task in a timely manner.

Dr. McCalla, Professor Glimm, and my inquisitive years of being a mathematician have influenced my work the most.

Equipment:
I worked in a PhD candidate computer lounge at the Glimm Lab in the Math Tower of Stony Brook and was given access to Stony Brook’s computing resources and student access to MATLAB and MAPLE. I worked independently on a personal computer.

References: (attached as a separate document due to word limit)