Impact of number of co-existing rotors and inter-electrode distance on accuracy of rotor localization

Abstract

Background Conflicting evidence exists on the efficacy of focal impulse and rotor modulation on atrial fibrillation ablation. A potential explanation is inaccurate rotor localization from multiple rotors coexistence and a relatively large (9–11 mm) inter-electrode distance (IED) of the multi-electrode basket catheter. Methods and results We studied a numerical model of cardiac action potential to reproduce one through seven rotors in a two-dimensional lattice. We estimated rotor location using phase singularity, Shannon entropy and dominant frequency. We then spatially downsampled the time series to create IEDs of 2–30 mm. The error of rotor localization was measured with reference to the dynamics of phase singularity at the original spatial resolution (IED = 1 mm). IED has a significant impact on the error using all the methods. When only one rotor is present, the error increases exponentially as a function of IED. At the clinical IED of 10 mm, the error is 3.8 mm (phase singularity), 3.7 mm (dominant frequency), and 11.8 mm (Shannon entropy). When there are more than one rotors, the error of rotor localization increases 10-fold. The error based on the phase singularity method at the clinical IED of 10 mm ranges from 30.0 mm (two rotors) to 96.1 mm (five rotors). Conclusions The magnitude of error of rotor localization using a clinically available basket catheter, in the presence of multiple rotors might be high enough to impact the accuracy of targeting during AF ablation. Improvement of catheter design and development of high-density mapping catheters may improve clinical outcomes of FIRM-guided AF ablation.

“Investigating the Optimal Recording Duration for Summarising Spatiotemporal Behaviours of Long Lifespan Rotors Using Phase Mapping of Non-Contact Electrograms During Persistent Atrial Fibrillation’’

“…Whatever, electrophysiology mapping system is used to mapping AF, there is a debate in the literature with regards to the required time duration of VEGMs to be used detecting/tracking rotors. Several studies have used ≤ 10 s [13][14][15], while others used segments ≥ 30 s [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Thus, our results are expressed in two groups; group A ≤ 30 s and group B > 30 s. In order to investigate the time duration needed to produce a representative rotor density map, two time segments in each group were selected (group A 10 -30 s, group B 45-60 s) to distinguish the difference of the spatiotemporal changes of rotors in each rotor density map in comparison with the rotor density maps of 300 s segment recording (gold standard).…”

Scale-invariant structures of spiral waves

“…The rotors were defined as the phase singularities of the phase map as described previously [12]. To make our work clinically applicable, the transmembrane potential derived from the model was converted to unipolar and subsequently to bipolar signals ( Figure 1B) [18].…”

Analytical approaches for myocardial fibrillation signals

“…We recently investigated how spatial resolution affects interpretation of AF recordings, expressing spatial resolution requirements as a linear function of the spatial wavelength, and found that high-density multipolar catheters provide sufficient resolution, but basket catheters are prone to false rotor detections [ 50 ]. Aronis et al considered the effects of multiple co-existing rotors on resolution requirements in an in silico study and found that including more than one rotor increased errors 10-fold, suggesting higher resolution requirements for cases with multiple sources [ 51 ]. Jacquemet used a statistical model to investigate the effects of interelectrode spacing and rotor number and showed an increase in false positive and false negative phase singularity detections with increasing interelectrode distance [ 52 ].…”