Personalization of Atrial Anatomy and Electrophysiology as a Basis for Clinical Modeling of Radio-Frequency Ablation of Atrial Fibrillation

Abstract

Multiscale cardiac modeling has made great advances over the last decade. Highly detailed atrial models were created and used for the investigation of initiation and perpetuation of atrial fibrillation. The next challenge is the use of personalized atrial models in clinical practice. In this study, a framework of simple and robust tools is presented, which enables the generation and validation of patient-specific anatomical and electrophysiological atrial models. Introduction of rule-based atrial fiber orientation produced a realistic excitation sequence and a better correlation to the measured electrocardiograms. Personalization of the global conduction velocity lead to a precise match of the measured P-wave duration. The use of a virtual cohort of nine patient and volunteer models averaged out possible model-specific errors. Intra-atrial excitation conduction was personalized manually from left atrial local activation time maps. Inclusion of LE-MRI data into the simulations revealed possible gaps in ablation lesions. A fast marching level set approach to compute atrial depolarization was extended to incorporate anisotropy and conduction velocity heterogeneities and reproduced the monodomain solution. The presented chain of tools is an important step towards the use of atrial models for the patient-specific AF diagnosis and ablation therapy planing.

Three-dimensional Multiscale Modelling and Simulation of Atria and Torso Electrophysiology

“…The first model that considered complex anisotropic anatomical structures and fibre directions was developed by (Harrild & Henriquez 2000). Later models such as those defined by (Seemann et al 2006;Al Abed et al 2010;Lu et al 2011;Burdumy et al 2012;Krueger et al 2012;McDowell et al 2012;Dongdong Deng et al 2012) were developed emphasizing the electrophysiological heterogeneity or the fibre orientation to provide knowledge concerning the mechanisms of excitation and investigate how to model the atrial fibrosis.…”

“…Regarding the atrial mesh quality, hexahedral voxels were used with higher homogeneous spatial resolution (0.3 mm), similarly as in (Aslanidi et al 2012;Burdumy et al 2012;Krueger et al 2012;Jacquemet 2015). Thanks to the high quality and regularity of the mesh, the stability of numerical computations is guaranteed (Lamata et al 2013).…”

“…Additionally, the BB was lengthened to join the SAN in the RA and to hug the LAA on its left side (Cabrera & Sánchez-Quintana 2013). Although the newest models already included these conduction bundles (Krueger et al 2012;Jacquemet 2015;McDowell et al 2015), they were not particularly focused on modelling neither the realistic anatomy of the PMs nor its special properties associated to the fibre orientation, conduction velocity or anisotropy ratios of the PMs.…”

“…Much like to tissue anisotropy, regional conduction velocities are of high relevance when modelling the normal behaviour of the atrium. Our model, unlike other previous models (Krueger et al 2012;Jacquemet 2015;McDowell et al 2015), has been also designed to consider conductivity at microscopic scale making easy to adapt this property to any other pathological and macroscopic condition.…”

“…In this sense, one of the first methods used to build human-specific torso models was firstly proposed by (Bradley et al 1997;Bradley et al 2000) who investigated how to fit geometric data of the human torso obtained from MRIs, with high-order bicubic Hermite surface elements. More recently, the inhomogeneous volumetric models proposed by (Krueger et al 2012;Lenkova et al 2012) allowed to adapt the shape of the torso models (see Figure 5.f and 1g) to different patient morphologies. These authors tried to mathematically address the inverse problem and then to determine the mechanisms associated to changes in the activation patterns and cardiac rhythms.…”