Alain Karma
Physics Department and Center for Interdisciplinary Research on Complex Systems
All of us routinely experience fluid turbulence when watching swirling leaves in Fall, swirling cream in steaming coffee all year around, or when fastening our seat belts on a rough airplane ride. Fortunately, most of us have not experienced wave turbulence in the heart. This more lethal form of turbulence produces a chaotic hearth rhythm that stops the heart from pumping blood and causes sudden cardiac arrest, a leading cause of death among industrialized nations. Medical doctors routinely defibrillate patients on the show ER and in real life. Some high risk patients can carry implantable defibrillators. However, reducing mortality in the wider population of patients who die suddenly and unpredictably from ventricular fibrillation has remained a major challenge. At the heart of this challenge is a quest for a fundamental understanding of electrical waves that propagate contraction through the main chambers of the heart. These highly nonlinear waves behave quite differently from the linear waves taught in freshman physics that propagate sound or light. Plane waves annihilate when they collide and can break up into rapidly rotating spiral-shaped waves seemingly analogous to swirling leaves, albeit lethal. Furthermore, wave propagation is governed by an electrical circuitry of bewieldering complexity at molecular, cellular, and organ scales. In this lecture, I will review the rich scientific history spanning four centuries that has lead to modern conceptualizations of fibrillation. I will also discuss how mathematical theories and computations have helped to provide insights into wave dynamics from a physics perspective that offers new prospects to tame cardiac chaos beyond the limitations of current therapies.