Abstract 14897: Activation Dyssynchrony Between Contact Multielectrode Mapping and Subsurface Near-Infrared Optical Mapping During Human Atrial Fibrillation

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Aleksei Mikhailov ◽  
Brian Hansen ◽  
Matthew Fazio ◽  
Stanislav Zakharkin ◽  
Jichao Zhao ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Action Potentials ◽  
Near Infrared ◽  
Optical Mapping ◽  
Patient Specific ◽  
Surface Activation ◽  
Multielectrode Arrays ◽  
Maximum Delay ◽  
Activation Times ◽  
Human Atrial Fibrillation

Due to complex 3D human atrial structure, atrial fibrillation (AF) mapping with multielectrode arrays (MEA) mostly represents surface activation. Therefore, MEA may not properly visualize patient specific AF mechanisms, which impairs ablation outcomes. Conversely, near-infrared optical mapping (NIOM) visualizes subsurface intramural activation and can efficiently reveal reentrant drivers responsible for AF maintenance. Delay between surface activation seen by MEA electrograms (EGMs) vs subsurface activation seen by NIOM optical action potentials (OAPs) occurs due to dyssynchrony between myocardium layers, especially during AF. Coronary perfused explanted human atria (n=7) were mapped with NIOM (0.3-0.9mm 2 resolution) and 64-electrode MEA (3mm 2 resolution). Unipolar EGMs were analyzed for the steepest negative deflection. The delay between [-dV/dtmax] of unipolar EGMs and corresponding optical action potentials (OAPs) was compared in 500ms and 300ms pacing and AF. Subsequent structural analysis was done by 9.4T MRI (154-180μm 3 resolution) with gadolinium enhancement and histology. Delay between EGM and OAP local activation times rate-dependently and heterogeneously increased from 6±3 ms and 10±4 ms during 500ms and 300ms pacing to 15±11 ms (with maximum delay 47±18 ms) during pacing induced AF (average cycle length 124±65ms). Large local OAP-EGM delay, seen during AF, correlates with higher fibrosis percentage and fiber twist (p<0.05). NIOM identified reentrant drivers maintaining AF, which were incorrectly visualized as multiple breakthroughs in 68% of MEA maps (n=22). Higher frequency leads to an increased activation discrepancy between EGM and NIOM caused by increased dyssynchrony in regions of higher fibrosis percentage and fiber twist, which may prevent MEA from proper identification of AF drivers in diseased fibrotic human atria. Reannotation of EGM activation based on NIOM may be required for correct AF mechanisms visualization.

scholarly journals Optical Mapping-Validated Machine Learning Improves Atrial Fibrillation Driver Detection by Multi-Electrode Mapping

2020 ◽  
Vol 13 (10) ◽  
Author(s):  
Alexander M. Zolotarev ◽  
Brian J. Hansen ◽  
Ekaterina A. Ivanova ◽  
Katelynn M. Helfrich ◽  
Ning Li ◽  
...  
Keyword(s):  
Machine Learning ◽  
Atrial Fibrillation ◽  
Near Infrared ◽  
Fourier Spectrum ◽  
Optical Mapping ◽  
Binary Classification ◽  
Future Application ◽  
Data Set ◽  
Frequency Spectra

Background: Atrial fibrillation (AF) can be maintained by localized intramural reentrant drivers. However, AF driver detection by clinical surface-only multielectrode mapping (MEM) has relied on subjective interpretation of activation maps. We hypothesized that application of machine learning to electrogram frequency spectra may accurately automate driver detection by MEM and add some objectivity to the interpretation of MEM findings. Methods: Temporally and spatially stable single AF drivers were mapped simultaneously in explanted human atria (n=11) by subsurface near-infrared optical mapping (NIOM; 0.3 mm 2 resolution) and 64-electrode MEM (higher density or lower density with 3 and 9 mm 2 resolution, respectively). Unipolar MEM and NIOM recordings were processed by Fourier transform analysis into 28 407 total Fourier spectra. Thirty-five features for machine learning were extracted from each Fourier spectrum. Results: Targeted driver ablation and NIOM activation maps efficiently defined the center and periphery of AF driver preferential tracks and provided validated annotations for driver versus nondriver electrodes in MEM arrays. Compared with analysis of single electrogram frequency features, averaging the features from each of the 8 neighboring electrodes, significantly improved classification of AF driver electrograms. The classification metrics increased when less strict annotation, including driver periphery electrodes, were added to driver center annotation. Notably, f1-score for the binary classification of higher-density catheter data set was significantly higher than that of lower-density catheter (0.81±0.02 versus 0.66±0.04, P <0.05). The trained algorithm correctly highlighted 86% of driver regions with higher density but only 80% with lower-density MEM arrays (81% for lower-density+higher-density arrays together). Conclusions: The machine learning model pretrained on Fourier spectrum features allows efficient classification of electrograms recordings as AF driver or nondriver compared with the NIOM gold-standard. Future application of NIOM-validated machine learning approach may improve the accuracy of AF driver detection for targeted ablation treatment in patients.

HUMAN ATRIAL FIBRILLATION TERMINATED BY TARGETED ABLATION OF LOCALIZED REENTRANT DRIVERS GUIDED BY DUAL-SIDED SIMULTANEOUS EPICARDIAL AND ENDOCARDIAL OPTICAL MAPPING

Heart Rhythm ◽  
2014 ◽  
Vol 11 (11) ◽  
pp. 2129-2130 ◽  
Author(s):  
B.J. Hansen ◽  
J. Zhao ◽  
T.A. Csepe ◽  
L.A. Jayne ◽  
N. Li ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Optical Mapping ◽  
Human Atrial Fibrillation

scholarly journals Phase synchrony reveals organization in human atrial fibrillation

2015 ◽  
Vol 309 (12) ◽  
pp. H2118-H2126 ◽  
Author(s):  
David Vidmar ◽  
Sanjiv M. Narayan ◽  
Wouter-Jan Rappel
Keyword(s):  
Atrial Fibrillation ◽  
Cardiac Arrhythmias ◽  
Spatial Dynamics ◽  
Spiral Waves ◽  
Temporal Organization ◽  
Coarse Grained ◽  
Phase Synchrony ◽  
Activation Times ◽  
High Phase ◽  
Human Atrial Fibrillation

It remains unclear if human atrial fibrillation (AF) is spatially nonhierarchical or exhibits a hierarchy of organization sustained by sources. We utilize activation times obtained at discrete locations during AF to compute the phase synchrony between tissue regions, to examine underlying spatial dynamics throughout both atria. We construct a binary synchronization network and show that this network can accurately define regions of coherence in coarse-grained in silico data. Specifically, domains controlled by spiral waves exhibit regions of high phase synchrony. We then apply this analysis to clinical data from patients experiencing cardiac arrhythmias using multielectrode catheters to simultaneously record from a majority of both atria. We show that pharmaceutical intervention with ibutilide organizes activation by increasing the size of the synchronized domain in AF and quantify the increase in temporal organization when arrhythmia changes from fibrillation to tachycardia. Finally, in recordings from 24 patients in AF we show that the level of synchrony is spatially broad with some patients showing large spatially contiguous regions of synchronization, while in others synchrony is localized to small pockets. Using computer simulations, we show that this distribution is inconsistent with distributions obtained from simulations that mimic multiwavelet reentry but is consistent with mechanisms in which one or more spatially conserved spiral waves is surrounded by tissue in which activation is disorganized.

scholarly journals Unmasking Arrhythmogenic Hubs of Reentry Driving Persistent Atrial Fibrillation for Patient‐Specific Treatment

2020 ◽  
Vol 9 (19) ◽  
Author(s):  
Brian J. Hansen ◽  
Jichao Zhao ◽  
Katelynn M. Helfrich ◽  
Ning Li ◽  
Alexander Iancau ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Near Infrared ◽  
Ex Vivo ◽  
Specific Treatment ◽  
Persistent Atrial Fibrillation ◽  
Patient Specific ◽  
Computational Simulations ◽  
3 Dimensional ◽  
Atrial Refractoriness

Background Atrial fibrillation (AF) driver mechanisms are obscured to clinical multielectrode mapping approaches that provide partial, surface‐only visualization of unstable 3‐dimensional atrial conduction. We hypothesized that transient modulation of refractoriness by pharmacologic challenge during multielectrode mapping improves visualization of hidden paths of reentrant AF drivers for targeted ablation. Methods and Results Pharmacologic challenge with adenosine was tested in ex vivo human hearts with a history of AF and cardiac diseases by multielectrode and high‐resolution subsurface near‐infrared optical mapping, integrated with 3‐dimensional structural imaging and heart‐specific computational simulations. Adenosine challenge was also studied on acutely terminated AF drivers in 10 patients with persistent AF. Ex vivo, adenosine stabilized reentrant driver paths within arrhythmogenic fibrotic hubs and improved visualization of reentrant paths, previously seen as focal or unstable breakthrough activation pattern, for targeted AF ablation. Computational simulations suggested that shortening of atrial refractoriness by adenosine may (1) improve driver stability by annihilating spatially unstable functional blocks and tightening reentrant circuits around fibrotic substrates, thus unmasking the common reentrant path; and (2) destabilize already stable reentrant drivers along fibrotic substrates by accelerating competing fibrillatory wavelets or secondary drivers. In patients with persistent AF, adenosine challenge unmasked hidden common reentry paths (9/15 AF drivers, 41±26% to 68±25% visualization), but worsened visualization of previously visible reentry paths (6/15, 74±14% to 34±12%). AF driver ablation led to acute termination of AF. Conclusions Our ex vivo to in vivo human translational study suggests that transiently altering atrial refractoriness can stabilize reentrant paths and unmask arrhythmogenic hubs to guide targeted AF driver ablation treatment.

Abstract 18402: Human Atrial Fibrillation Drivers Seen Simultaneously by Focal Impulse and Rotor Mapping and High-resolution Optical Mapping

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Brian J Hansen ◽  
Carey Briggs ◽  
Brandon T Moore ◽  
Thomas A Csepe ◽  
Ning Li ◽  
...  
Keyword(s):  
High Resolution ◽  
Near Infrared ◽  
Optical Mapping ◽  
Ex Vivo ◽  
Dominant Frequency ◽  
Patient Specific ◽  
Analysis Tool ◽  
Basket Catheter ◽  
Left And Right ◽  
Right Atria

Background: A mechanism of AF maintenance has been suggested to be a limited number of patient-specific AF drivers seen by optical mapping in animals and now Focal Impulse and Rotor Mapping (FIRM) in patients. The higher resolution optical mapping can only be performed ex vivo and, thus, these two different mapping approaches have never been evaluated simultaneously in human hearts. Methods: Coronary-perfused explanted human atria (n=5, 19-57 y.o.) were optically mapped using voltage sensitive near-infrared di-4-ANBDQBS with 2-4 high resolution CMOS cameras (100x100 pixels with 330-1000μM resolution) simultaneously with a 64-electrode basket catheter or a 64-electrode custom flat catheter from either the endocardium or epicardium. AF (>10 min, 6.8±2.1Hz) was induced by perfusion of adenosine (10-100μM) and/or isoproterenol (10-100nM). AF drivers were defined as localized stable reentrant activity in areas of highest dominant frequency for optical mapping, while unipolar signals from the catheters were analyzed using experienced FIRM user interpretation and RAP, a signal analysis tool that highlights driver regions on commercially available systems. Results: Optical mapping identified reentrant AF drivers in 7/8 episodes of AF in both the left and right atria. Interestingly, one episode of AF was driven by two competing reentrant drivers. Six AF drivers seen by optical mapping were also seen with the same location and rotation by FIRM, while FIRM identified an AF driver in an 8th episode from an endocardial basket that was unseen by optical mapping from the epicardium. In one episode, the intramural AF driver was only defined by dual sided optical mapping and unseen by endocardial FIRM. Conclusions: Our study demonstrates that most localized reentrant AF drivers in ex vivo human hearts have similar spatiotemporal characteristics whether identified by high resolution optical mapping or FIRM and may represent the clinical phenomena seen in AF patients.

The role of angiotensin in electrophysiological gap junction remodeling in human atrial fibrillation

2004 ◽  
Vol 52 (S 1) ◽  
Author(s):  
S Dhein ◽  
A Boldt ◽  
J Garbade ◽  
L Polontchouk ◽  
U Wetzel ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Gap Junction ◽  
Human Atrial Fibrillation
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