Rotor Tracking Using Phase of Electrograms Recorded During Atrial Fibrillation

Abstract

Extracellular electrograms recorded during atrial fibrillation (AF) are challenging to interpret due to the inherent beat-to-beat variability in amplitude and duration. Phase mapping represents these voltage signals in terms of relative position within the cycle, and has been widely applied to action potential and unipolar electrogram data of myocardial fibrillation. To date, however, it has not been applied to bipolar recordings, which are commonly acquired clinically. The purpose of this study is to present a novel algorithm for calculating phase from both unipolar and bipolar electrograms recorded during AF. A sequence of signal filters and processing steps are used to calculate phase from simulated, experimental, and clinical, unipolar and bipolar electrograms. The algorithm is validated against action potential phase using simulated data (trajectory centre error <0.8 mm); between experimental multi-electrode array unipolar and bipolar phase; and for wavefront identification in clinical atrial tachycardia. For clinical AF, similar rotational content (R 2 = 0.79) and propagation maps (median correlation 0.73) were measured using either unipolar or bipolar recordings. The algorithm is robust, uses standard signal processing techniques, and accurately quantifies AF wavefronts and sources. Identifying critical sources, such as rotors, in AF, may allow for more accurate targeting of ablation therapy and improved patient outcomes.Electronic supplementary materialThe online version of this article (doi:10.1007/s10439-016-1766-4) contains supplementary material, which is available to authorized users.

Unraveling the Underlying Arrhythmia Mechanism in Persistent Atrial Fibrillation

“…This has previously been validated and shown to perform well against simulated, experimental, and clinical data in atrial tachycardia and AF, with the additional benefit of being able to use bipolar data, which is less susceptible to noise artifact. 11 In the mapping technique substudy, we repeated our analysis using the alternative technique, in patients with an atrial tachycardia, relatively longer lasting PS, and only short PS duration. Both methods yielded similar results, which while accepting this was only performed in a proportion of the patients is reassuring in terms of the scientific validity of our chosen main approach.…”

“…This analysis method has previously been extensively described, 11 and further methodology specific to this study is presented in Methods in the Data Supplement.…”

“…Post hoc datasets were subjected to repeat analysis using an alternative AF phase mapping technique, 11 assessed in the following categories: organized atrial tachycardia (n=3), longer lasting PS duration (n=2), and shorter PS duration (n=2). The atrial tachycardia group consists of 1 patient who presented and was mapped in LA tachycardia (and was subsequently excluded from our main results for PsAF) and 2 patients who presented in AF and developed atrial tachycardia during the ablation procedure.…”

Iterative navigation of multipole diagnostic catheters to locate repeating‐pattern atrial fibrillation drivers

“…As an alternative to basket catheters, Roney et al . [36] explored multipolar spiral catheters, which provide higher spatial resolution but need to map the entire atrial surface. To construct the activation map of the atria, the recordings were taken from several locations and subsequently integrated into a full 3D electroanatomical map with higher spatial resolution.…”

Spurious Rotor Detection During Atrial Fibrillation: Phase Singularities in Fact Reflect Blurred Conduction Block

“…The two filtering methods were sinusoidal recomposition [5] and a recently described frequency domain filter that emphasises local deflection energy. [6] The two phase reconstruction methods were the Hilbert transform and time-delay embedding, the latter with a time delay of 25% of the AF cycle length. Locations containing a PS were detected using estimated phase signals, following the approach described by Kuklik et al [7], where a PS is only detected if a sudden phase transition > π occurs in two paths encircling a point, in this case formed by electrodes at 1.5 mm and 3 mm distance.…”