scholarly journals Simulation of Spiral Waves and Point Sources in Atrial Fibrillation with Application to Rotor Localization

2017 ◽  
Author(s):  
Prasanth Ganesan ◽  
Kristina E. Shillieto ◽  
Behnaz Ghoraani
Keyword(s):  
Atrial Fibrillation ◽  
Spiral Waves ◽  
Point Sources

scholarly journals Mechanisms of Atrial Fibrillation – Reentry, Rotors and Reality

2014 ◽  
Vol 3 (2) ◽  
pp. 90 ◽  
Author(s):  
Jonathan W Waks ◽  
Mark E Josephson ◽  
◽  
Keyword(s):  
Atrial Fibrillation ◽  
Clinical Practice ◽  
Catheter Ablation ◽  
20Th Century ◽  
Experimental Studies ◽  
Therapeutic Targets ◽  
Spiral Waves ◽  
Historical Understanding ◽  
New Strategies ◽  
Complex Fractionated Atrial Electrograms

Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice, yet our understanding of the mechanisms that initiate and sustain this arrhythmia remains quite poor. Over the last 50 years, various mechanisms of AF have been proposed, yet none has been consistently observed in both experimental studies and in humans. Recently, there has been increasing interest in understanding how spiral waves or rotors – which are specific, organised forms of functional reentry – sustain human AF and how they might be therapeutic targets for catheter-based ablation. The following review describes the historical understanding of reentry and AF mechanisms from earlier in the 20th century, advances in our understanding of mechanisms that are able to sustain AF with a focus on rotors and complex fractionated atrial electrograms (CFAEs), and how the study of AF mechanisms has resulted in new strategies for treating AF with novel forms of catheter ablation.

scholarly journals Modern aspects of surgical treatment of patients with atrial fibrillation. Development of uniform criteria for selecting patients for radiofrequency ablation

2020 ◽  
pp. 58-64
Author(s):  
I. A. Libov ◽  
I. M. Mayorov ◽  
L. P. Porunov
Keyword(s):  
Atrial Fibrillation ◽  
Surgical Treatment ◽  
Radiofrequency Catheter Ablation ◽  
High Probability ◽  
Surgical Intervention ◽  
Spiral Waves ◽  
Clinical Effects ◽  
Strategy Selection ◽  
Medication Treatment

The article discusses the issues concerning the treatment of patients with the atrial fibrillation (AF), analyzes the indications for execution, in the absence of the effect of medication treatment, radiofrequency catheter ablation (RFA) of the lung vein entries and electrical spiral waves in the atria or rotors, the clinical effects of this procedure, assesses the contribution of focal activity in maintaining the persistent AF. The influence of concomitant pathology and anatomical-morphological peculiarities of the heart on early and distant RFA results in patients with persistent AF is discussed. The success and efficacy of AF surgical treatment depends not only on the method and technology of the chosen procedure, but also on the risk factors for the recurrence of AF (so-called predictors). Radio-frequency ablation, being an invasive surgery, has its own spectrum of possible complications and high economic component, which predetermines the necessity to predict the efficiency of the procedure, i.e. preoperative determination of the patient group, in which this type of treatment will be justified, and the expected efficiency and safety – higher than the probability of complications. The study of this problem and the development of criteria for selecting patients with AF will allow predicting the effectiveness of surgical intervention with high probability, which in turn will contribute to the correct strategy selection.

scholarly journals Three dimensional reconstruction to visualize atrial fibrillation activation patterns on curved atrial geometry

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0249873
Author(s):  
Ricardo Abad ◽  
Orvil Collart ◽  
Prasanth Ganesan ◽  
A. J. Rogers ◽  
Mahmood I. Alhusseini ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Three Dimensional ◽  
Spiral Waves ◽  
Patient Specific ◽  
Activation Patterns ◽  
Density Maps ◽  
Median Correlation ◽  
Geometric Curvature ◽  
Dimensional Reconstruction ◽  
Phase Singularities

Background The rotational activation created by spiral waves may be a mechanism for atrial fibrillation (AF), yet it is unclear how activation patterns obtained from endocardial baskets are influenced by the 3D geometric curvature of the atrium or ‘unfolding’ into 2D maps. We develop algorithms that can visualize spiral waves and their tip locations on curved atrial geometries. We use these algorithms to quantify differences in AF maps and spiral tip locations between 3D basket reconstructions, projection onto 3D anatomical shells and unfolded 2D surfaces. Methods We tested our algorithms in N = 20 patients in whom AF was recorded from 64-pole baskets (Abbott, CA). Phase maps were generated by non-proprietary software to identify the tips of spiral waves, indicated by phase singularities. The number and density of spiral tips were compared in patient-specific 3D shells constructed from the basket, as well as 3D maps from clinical electroanatomic mapping systems and 2D maps. Results Patients (59.4±12.7 yrs, 60% M) showed 1.7±0.8 phase singularities/patient, in whom ablation terminated AF in 11/20 patients (55%). There was no difference in the location of phase singularities, between 3D curved surfaces and 2D unfolded surfaces, with a median correlation coefficient between phase singularity density maps of 0.985 (0.978–0.990). No significant impact was noted by phase singularities location in more curved regions or relative to the basket location (p>0.1). Conclusions AF maps and phase singularities mapped by endocardial baskets are qualitatively and quantitatively similar whether calculated by 3D phase maps on patient-specific curved atrial geometries or in 2D. Phase maps on patient-specific geometries may be easier to interpret relative to critical structures for ablation planning.

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 Standardised Framework for Quantitative Analysis of Fibrillation Dynamics

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Xinyang Li ◽  
Caroline H. Roney ◽  
Balvinder S. Handa ◽  
Rasheda A. Chowdhury ◽  
Steven A. Niederer ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Open Source Software ◽  
Spiral Waves ◽  
Data Sets ◽  
Research Groups ◽  
Phase Singularity ◽  
Custom Made ◽  
Spatio Temporal ◽  
Comprehensive Framework ◽  
Temporal Action

Abstract The analysis of complex mechanisms underlying ventricular fibrillation (VF) and atrial fibrillation (AF) requires sophisticated tools for studying spatio-temporal action potential (AP) propagation dynamics. However, fibrillation analysis tools are often custom-made or proprietary, and vary between research groups. With no optimal standardised framework for analysis, results from different studies have led to disparate findings. Given the technical gap, here we present a comprehensive framework and set of principles for quantifying properties of wavefront dynamics in phase-processed data recorded during myocardial fibrillation with potentiometric dyes. Phase transformation of the fibrillatory data is particularly useful for identifying self-perpetuating spiral waves or rotational drivers (RDs) rotating around a phase singularity (PS). RDs have been implicated in sustaining fibrillation, and thus accurate localisation and quantification of RDs is crucial for understanding specific fibrillatory mechanisms. In this work, we assess how variation of analysis parameters and thresholds in the tracking of PSs and quantification of RDs could result in different interpretations of the underlying fibrillation mechanism. These techniques have been described and applied to experimental AF and VF data, and AF simulations, and examples are provided from each of these data sets to demonstrate the range of fibrillatory behaviours and adaptability of these tools. The presented methodologies are available as an open source software and offer an off-the-shelf research toolkit for quantifying and analysing fibrillatory mechanisms.

UNSTABLE CARDIAC SINGULARITIES MAY LEAD TO ATRIAL FIBRILLATION

2011 ◽  
Vol 21 (04) ◽  
pp. 1141-1151 ◽  
Author(s):  
C. L. WEBBER ◽  
Z. HU ◽  
J. G. AKAR
Keyword(s):  
Atrial Fibrillation ◽  
Full Range ◽  
Central Line ◽  
Recurrence Quantification Analysis ◽  
Spiral Waves ◽  
Atrial Arrhythmias ◽  
Recurrence Plots ◽  
Recurrence Quantification ◽  
Quantification Analysis ◽  
Derivatives Of

A total of 53 atrial electrograms were recorded from 12 human patients diagnosed with different degrees of atrial arrhythmias and fibrillation, but not atrial flutter. The atrial waves were highly complex, noisy, nonuniform, nonlinear, and nonstationary in time and well suited for recurrence quantification analysis (RQA), spectral analysis (FFT) and atrial rate (AR) measurements. Differing degrees of atrial arrhythmias were quantified by measuring singularities in the electrograms. Singularities were defined as the maximum periods of relative isopotential squared (msec2) and presented as unfilled squares along the central line of identity (LOI) on recurrence plots. These nonsolid (unfilled) squares indicate that most singularities were unstable with noisy baselines. All measured variables were plotted against their corresponding unstable singularities. The best correlations were found for variables Vmaxand Laminar over the full range of log10(singularity). That is, the higher the degree of fibrillation the smaller the size of the singularity and the shorter Vmaxand Laminar. The shorter singularities are associated with faster spiral waves. However, since Vmaxand Laminar are direct derivatives of Singularity, this variable remains the sole best quantifier of choice to identify aberrant pacemaker regions.

scholarly journals Heterogeneity of the Frequency Domain Patterns in Persistent Atrial Fibrillation

2018 ◽  
Author(s):  
Shahriar Iravanian ◽  
Jonathan J Langberg
Keyword(s):  
Atrial Fibrillation ◽  
Frequency Domain ◽  
Single Mother ◽  
Persistent Atrial Fibrillation ◽  
Clinical Problem ◽  
Dominant Frequency ◽  
Frequency Domain Analysis ◽  
Spiral Waves ◽  
Frequency Resolution ◽  
Frequency Pattern

AbstractBackgroundPersistent atrial fibrillation (AF) has remained a challenging clinical problem. The mechanisms of persistent AF are still subject to debate. Both a single mother-rotor with fibrillatory conduction and multiple meandering spiral waves have been proposed to explain persistent AF. Previous frequency domain studies have reported the presence of dominant frequency (DF) gradient (a marker of single mother-rotor) in paroxysmal, but not persistent AF.Methods and ResultsWe performed temporally-dense high-resolution frequency domain analysis of 10-40 minutes segments of intracardiac signals recorded in 24 patients undergoing ablation of persistent AF. We observed two predominant patterns. The expected signature of the mother-rotor mechanism was observed in 38% of the patients. The frequency pattern in 54% consisted of two or more distinct frequency peaks with no obvious gradient, which is consistent with multiple separate primary spiral waves in electrophysiologically heterogeneous areas of atria. The average measured number of rotors per case was 1.71 ± 0.32, which provides a lower limit on the actual number of rotors. The single-zone pattern was exclusively seen in patients who were on a membrane-active antiarrhythmic medication at the time of ablation (P < 0.005).ConclusionsAF is a heterogeneous disorder. High-frequency resolution analysis is a useful tool to detect the underlying mechanisms of AF and to classify it into patterns consistent with a single mother-rotor vs. multiple meandering wavelets.

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