Optimal Termination of Spiral Waves Associated with Cardiac Arrhythmias

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The objective of this award is the development of novel methodologies for treating cardiac arrhythmias associated with abnormal electrical activity in the heart. This will include the computation of energy-optimal stimuli which drive the states of myocardial cells to a region of phase space for which they become nearly synchronized, thereby terminating spiral wave activity and preventing spiral wave reentry. The algorithm used to accomplish this will involve new computational approaches for finding appropriate target regions of phase space and solving the Hamilton-Jacobi-Bellman equation in higher dimensions. Another methodology will use the action potential duration restitution curve, which is an experimentally measurable function that describes the duration of an action potential as a function of the time since the end of the preceding action potential. Given this curve, the methods of dynamic programming will be applied to determine an optimal pulse train within a family of possibilities for synchronization of myocardial activity.Cardiac arrhythmias can disrupt the coordination that is essential for the effective pumping of blood, and can lead to cardiac arrest. Survivors of cardiac arrest often receive an implantable cardioverter defibrillator (ICD), but defibrillating shocks from ICDs can lead to fibrosis in the myocardium, making it necessary to use stronger defibrillating shocks. The shocks can also cause adverse short-term side effects such as intense chest pain and post-shock dysfunction. If successful, this research will represent an early step toward the use of energy-optimal stimuli for ICDs, which would reduce the need for surgical replacement of their batteries,and might mitigate some of the deleterious side effects of defibrillation. This work will also contribute to the development of computational tools which can be used to find optimal control strategies in a wide range of applications.