“Low energy stimuli for spiral wave dynamics control”

JORGE CASTRO A, MATÍAS RAFTI B, ALBERTO ALBESA ,B, JORGE CARBALLIDO-LANDEIRA A, FLAVIO H. FENTON C AND ALBERTO P. MUÑUZURI A

Leon

Conferencia; 5th International Scientific Conference on Physics and Control; 2011

Universidad de Leon

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia worldwide affecting 2.2 million people in the United States alone. Complications associated with chronic AF include increased risk for both thromboembolism and stroke. Left untreated, paroxysmal AF often progresses to permanent AF, which is resistant to therapy. Although underlying anatomic or pathophysiological factors may fuel this progression, AF itself may lead to its own perpetuation through electric, structural, and metabolic remodeling of atrial tissue. The realization that AFbegets AF has led to management strategies that are designed to avoid the progression of AF by reducingthe frequency and duration of AF episodes [1].Among these strategies, a new method to terminate fast atrial tachycardias and AF has been recently developed within the context of animal experimentation [2]. In this method, electrodes located at a small distance from the heart deliver a train of low-voltage shocks at a rapid rate. The idea underlying is that during the low-energy shocks, small intrinsic conductivity discontinuities behave as internal virtual electrodes that actually serve as activation sites (or secondary sources) if the field strength depolarizes the tissue beyond the excitation threshold. This method presents many advantages comparing with previous methods.Although the method has been successfully tested in laboratory animals, a deep understanding of the mechanisms underlying is still to be done. In such a sense, we will presentin this contribution results aiming to understand the previous mechanism in a completely different system although equivalent in many senses [3]. We will analyze the same problem within the context of chemical pattern forming chemical reactions (Belousov-Zhabotinsky reaction). Effectively, BZ reaction is considered to be a paradigm for pattern formation research as the mechanisms here studied can be easily extrapolated to more complex systems such as the cardiac tissue. Spiral waves are believe to be responsible of Atrial Fibrilation in the heart and can be easily observed in BZ reaction. In this system, we apply low-energy stimuli and demonstrate the effectiveness of the method. The presence of conductivity discontinuities in the system will also be modeled and the results agree with the experiments in cardiology.Experimental results and numerical simulations will present clearly the deep mechanism underlying.Refs:Waktare JE. Cardiology patient page: atrial fibrillation. Circulation. 2002;106:14 16. Heart disease and stroke statistics: 2007 update.Circulation. 2007;115: e69 e171. Nattel S, Opie LH. Controversies in atrial fibrillation. Lancet. 2006;367: 262 272. Wijffels M, Kirchhof C, Dorland R, Allessie MA. Atrial fibrillation begets atrial fibrillation: a study in awake chronically instrumented goats. Circulation. 1995;92:1954 1968.Fenton FH, Luther S, Otani NF, Cherry EM, Pumir A, Bodenschatz E, Krinsky V, Gilmour RF Jr. ermination of atrial fibrillation using pulsed low-energyfar field stimulation Circulation 120, 467-476: 2009Matias Rafti, Alberto Albesa, Flavio H. Fenton and Alberto P. Muñuzuri, in preparation