Body surface localization of left and right atrial high-frequency rotors in atrial fibrillation patients: A clinical-computational study

Abstract

BACKGROUND Ablation is an effective therapy in patients with atrial fibrillation (AF) in which an electrical driver can be identified. OBJECTIVE The aim of this study was to present and discuss a novel and strictly noninvasive approach to map and identify atrial regions responsible for AF perpetuation. METHODS Surface potential recordings of 14 patients with AF were recorded using a 67-lead recording system. Singularity points (SPs) were identified in surface phase maps after band-pass filtering at the highest dominant frequency (HDF). Mathematical models of combined atria and torso were constructed and used to investigate the ability of surface phase maps to estimate rotor activity in the atrial wall. RESULTS The simulations show that surface SPs originate at atrial SPs, but not all atrial SPs are reflected at the surface. Stable SPs were found in AF signals during 8.3% ± 5.7% vs 73.1% ± 16.8% of the time in unfiltered vs HDF-filtered patient data, respectively (P < .01). The average duration of each rotational pattern was also lower in unfiltered than in HDF-filtered AF signals (160 ± 43 ms vs 342 ± 138 ms; P < .01), resulting in 2.8 ± 0.7 rotations per rotor. Band-pass filtering reduced the apparent meandering of surface HDF rotors by reducing the effect of the atrial electrical activity occurring at different frequencies. Torso surface SPs representing HDF rotors during AF were reflected at specific areas corresponding to the fastest atrial location. CONCLUSION Phase analysis of surface potential signals after HDF filtering during AF shows reentrant drivers localized to either the left atrium or the right atrium, helping in localizing ablation targets.

Not all rotors, effective ablation targets for nonparoxysmal atrial fibrillation, are included in areas suggested by conventional indirect indicators of atrial fibrillation drivers: ExTRa Mapping project

“…However, as far as we know, the above‐mentioned phase mapping systems contain several limitations as follows: offline use thus requiring a long period for AF visualization, low spatial density of <4 signals/cm 2 , and insufficient verification of the imaging algorithms, resulting from poor electrode contact17 or constraints due to the inverse problem 18. Moreover, those phase mapping systems are not currently available in our country, Japan.…”

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

“…In this situation, a dipolar distribution characterizes the surface potential maps with negative and positive time integral distributions localized in the frontal upper right and lower left quadrants, respectively. This general behaviour is also in agreement with previous computational atrial-torso models (Aslanidi et al 2011;Krueger et al 2013;Rodrigo et al 2014). However, these previous models used a simplified torso anatomy or considered only a limited number of organs what may influence the pathway followed by the electrical wavefront and then the morphology of the signals registered at the torso surface.…”

Noninvasive Identification of Atrial Fibrillation Drivers: Simulation and Patient Data Evaluation

“…In this work, we have demonstrated that reconstruction errors can be mostly attributed to a loss of complexity, quantified in terms of the number of simultaneous phase singularities. This loss of complexity is consistent with a mutual cancellation of propagation wavefronts with opposed directions [10] that may not be retrievable by solving the inverse problem.…”

“…For each simulation, a uniform mesh of unipolar EGMs was calculated surrounding the epicardial surface (1 mm distance) under the assumption of a homogenous, unbounded and quasi-static conducting medium by summing up all effective dipole contributions over the entire model [10]. Computed electrograms were stored for processing at a sampling frequency of 500 Hz.…”