Seminario promosso dall'Unità di Fisica non lineare e modelli matematici

Programma:

ore 11.00-11.40 – Modeling and Visualization of the Complex Wave Dynamics in the Heart 
                             Prof. Flavio H. Fenton, School of Physics, Georgia Institute of Technology

Abstract 
The heart is an electro-mechanical system in which, under normal conditions, electrical waves propagate in a coordinated manner to initiate an efficient contraction. In pathologic states, single and multiple rapidly rotating spiral and scroll waves of electrical activity can appear and generate complex spatiotemporal patterns of activation that inhibit contraction and can be lethal if untreated.

In this talk we will show several dynamics of these waves experimentally and then describe how we use mathematical models to simulate and study these waves. This talk will serve as a bridge to the next two talks that deal on different methods to terminate these deadly arrhythmias.

ore 11.45-12.20 – Low-Energy Control of Cardiac Arrhythmias
                              Prof. Stefan Luther, Max Planck Institute for Dynamics and Self-Organization, Goettingen, Germany

Abstract 
Cardiac fibrillation is driven by rotating electrical waves (vortices) that interact with each other and with the heterogeneous anatomical substrate. Current defibrillation techniques use high-energy electric shocks to end cardiac fibrillation by terminating all excitation waves in the heart at once. Although defibrillators are used routinely, treatments are often associated with severe side effects, including tissue damage and traumatic pain. In contrast, low-energy control of fibrillation aims to reduce the energy required to terminate arrhythmias by efficiently controlling the vortex dynamics underlying fibrillation.

In general, the advancement of low-energy control approaches encounters two scientific challenges, i.e. (i) the visualization of intramural vortex dynamics during cardiac arrhythmias and (ii) the control of multiple vortices simultaneously using pulsed electric fields.

Regarding these challenges, we report on experimental and numerical data on the role of electric field geometry and pacing protocols on the termination efficacy, e.g. field geometry and pacing protocols that control multiple vortices simultaneously, resulting in efficient tissue synchronization and termination of arrhythmias.

ore 12.20-13.00 – Advanced computational modelling in the design of new cardiac radiofrequency ablation strategies
                             Prof. Luca Gerardo-Giorda, Basque Center for Applied Mathematics, Bilbao, Spain

Abstract 
Radiofrequency ablation (RFA) is a common procedure in cardiac catheterization for the treatment of arrhythmias. Although globally a pretty safe procedure, it may present some risk. Thrombus formation can occur during RFA at the electrode-tissue interface when the temperature exceeds 80°C. Steam pops are caused by tissue overheating at 100°C, and may trigger explosive ruptures of myocardium. If the steam pop occurs sufficiently deep in the tissue, or if the RFA procedure is performed on atria, whose walls are thinner than the ones of the ventricles, such explosive rupture may result in a perforation of the cardiac chamber wall, and in dramatic hemorrhagic events.

We will discuss the role of advanced computational modelling in designing safer and more efficient ablation strategies to be applied in the clinical environment, and present the strategy we developed in collaboration with the hospital de la Santa Creu i San Pau in Barcelona.