A bilayer representation of the human atria

Abstract

Abstract-Atrial fibrillation is the most commonly encountered clinical arrhythmia. Despite recent advances in treatment by catheter ablation, its origin is still incompletely understood and it may be difficult to treat. Computer modelling offers an attractive complement to experiment. Simulations of fibrillation, however, are computationally demanding since the phenomenon requires long periods of observation. Because the atria are thin walled structures, they are often modelled as surfaces. However, this may not always be appropriate as the crista terminalis and pectinate muscles are discrete fibrous structures lying on the endocardium and cannot be incorporated into the surface. In the left atrium, there are essentially two layers with an abrupt change in fibre orientation between them. We propose a double layer method, using shell elements to incorporate wall thickness, where fibre direction is independent in each layer and layers are electrically linked. Starting from human multidetector CT (MDCT) images, we extracted surfaces for the atria and manually added a coronary sinus. Propagation of electrical activity was modelled with the monodomain equation. Results indicate that major features are retained while reducing computation cost considerably. Meshes based on the two layer approach will facilitate studies of AF.

A bilayer model of human atria: mathematical background, construction, and assessment

“…In such cases, variation of the surface elements thickness can also be considered wherein all elements are considered as 3D with an additional factor defining the thickness (35). This is similar to the linear coupling elements where a cross-sectional area was required.…”

Understanding the Beat-to-Beat Variations of P-Waves Morphologies in AF Patients During Sinus Rhythm: A Scoping Review of the Atrial Simulation Studies

“…AF induces this type of structural remodeling, based on experimental findings from goats (Eckstein et al, 2011), while it was revealed that this dissociation increases AF stability (Gharaviri et al, 2012b, 2017; Verheule et al, 2013). A methodology for the creation of a bilayer model of human atria, using CT images, is proposed by Vigmond et al (2013), where the difference between RA and LA thickness, as well as the main anatomical structures and fiber orientation, is taken into account. The dual layer approach has also been adopted to examine the effectiveness of different radiofrequency ablation strategies (Bayer et al, 2016).…”