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Measuring the mean cycle length (CL) of a rapidly beating heart is considered an efficient way to monitor arrhythmia such as atrial fibrillation (AF). Routinely, sequential CL mapping, using contact catheters in the atria, provides indications on the localization of regions involved in AF. In particular, this technique helps the practitioner, during ablation procedures, to identify some features of the arrhythmia, as, for instance, the driving atrium, or the fastest regions, or its complexity. In this study, we propose a non invasive mapping of CL (niCL), using phase information extracted from electrocardiographic imaging signals (ECGI). niCL mapping provides with a real time ablation planning to the bedside of patients, prior to ablation procedure. The results of this study validate the method in showing a direct correlation between endocavitory (inside the heart) measurements of CL (enCL) and niCL mapping. [ABSTRACT FROM PUBLISHER]

Atrial fibrosis is known to be a factor in the perpetuation of atrial arrhythmia. Despite the thinness of atrial tissue, the fibrosis distribution may not be homogeneous through the entire thickness of the atria. This study aims to elucidate the respective influences of a transmural and a non-transmural distribution of fibrosis, described as a slow conduction zone, on the perpetuation of an arrhythmic episode, compared to a control situation. We used a bilayer monodomain representation of the atria that included transmural heterogeneities of fibre organisation. This model allowed long simulations for a sustainable computational load. We observed that when the fibrosis was transmural, the centre of the rotor was anchored in the slow conduction zone and was stable during a 10 seconds simulation, whereas the other simulations showed meandering rotors that disappeared after a few seconds. This study provided insight into the influence of transmural fibrosis on atrial arrhythmia perpetuation. In our model framework, only a transmural fibrosis distribution had a stabilizing effect on reentrant circuits. The bilayer model proved to be a good trade-off between accuracy and speed for observing the influence of transmural heterogeneities on atrial arrhythmia over long periods. [ABSTRACT FROM PUBLISHER]