BME PhD Prospectus Defense - Oliver Bates

12:00 pm on Wednesday, July 10, 2013
44 Cummington, Room 705
Committee members:
Peter Spector, M.D.* (Advisor)
Bela Suki, Ph.D.** (Co-Advisor)
Solomon Eisenberg, Ph.D.**
Jason Ritt, Ph.D.**
* Fletcher Allen Health Care & University of Vermont College of Medicine
** Department of Biomedical Engineering, Boston University College of Engineering

Title: Characterizing and Constraining the Emergence of Multi-Wavelet Reentry in a Computational Model of Excitable Media

Atrial fibrillation (AF) is the most commonly seen arrhythmia in clinical practice with an estimated 6.7 million cases in the United States and Europe. It is diagnosed on the electrocardiogram (ECG/EKG), where it is characterized by the replacement of consistent P waves by rapid oscillations (fibrillatory waves). Symptoms can include heart palpitations, chest pain or pressure, lightheadedness and fatigue. While AF itself is generally not life-threatening, it is a severe complicating factor in other heart disease and is linked with increased risk of stroke, heart failure, and all-cause mortality. The mechanisms of AF, while still unknown, are believed to involve two processes: spontaneous depolarization at aberrant foci and reentrant propagation. Recent studies have lent compelling support to the Multiple Wavelet Hypothesis first advanced in the 1950’s in which several distinct waves of excitation meander chaotically throughout the atrial myocardium. Despite this gained insight into the drivers of AF, it remains unclear how to treat it clinically. This stems in large part from an inadequate understanding of the dynamics of multi-wavelet reentry and the rules that guide its emergence and maintenance. In this work, a computational model for propagation in excitable media will be used to elucidate the fundamental properties of chaotic reentry. The characteristics of its appearance and maintenance will be investigated relative to substrate properties. Finally, the impact of physical substrate alterations on the inducibility and sustainability of multi-wavelet reentry will be investigated as a step towards developing improved procedures for AF treatment.