scholarly journals Computational Analysis of Mapping Catheter Geometry and Contact Quality Effects on Rotor Detection in Atrial Fibrillation

2021 ◽  
Vol 12 ◽  
Author(s):  
Chiara Bartolucci ◽  
Claudio Fabbri ◽  
Corrado Tomasi ◽  
Paolo Sabbatani ◽  
Stefano Severi ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Structural Parameters ◽  
Spiral Wave ◽  
Spatial Location ◽  
Electrode Spacing ◽  
Patient Specific ◽  
Electrode Distance ◽  
Detection Failure ◽  
Distance Position ◽  
Mapping Catheter

Atrial fibrillation (AF) is the most common cardiac arrhythmia and catheter mapping has been proved to be an effective approach for detecting AF drivers to be targeted by ablation. Among drivers, the so-called rotors have gained the most attention: their identification and spatial location could help to understand which patient-specific mechanisms are acting, and thus to guide the ablation execution. Since rotor detection by multi-electrode catheters may be influenced by several structural parameters including inter-electrode spacing, catheter coverage, and endocardium-catheter distance, in this study we proposed a tool for testing the ability of different catheter shapes to detect rotors in different conditions. An approach based on the solution of the monodomain equations coupled with a modified Courtemanche ionic atrial model, that considers an electrical remodeling, was applied to simulate spiral wave dynamics on a 2D model for 7.75 s. The developed framework allowed the acquisition of unipolar signals at 2 KHz. Two high-density multipolar catheters were simulated (Advisor™ HD Grid and PentaRay®) and placed in a 2D region in which the simulated spiral wave persists longer. The configuration of the catheters was then modified by changing the number of electrodes, inter-electrodes distance, position, and atrial-wall distance for assessing how they would affect the rotor detection. In contact with the wall and at 1 mm distance from it, all the configurations detected the rotor correctly, irrespective of geometry, coverage, and inter-electrode distance. In the HDGrid-like geometry, the increase of the inter-electrode distance from 3 to 6 mm caused rotor detection failure at 2 mm distance from the LA wall. In the PentaRay-like configuration, regardless of inter-electrode distance, rotor detection failed at 3 mm endocardium-catheter distance. The asymmetry of this catheter resulted in rotation-dependent rotor detection. To conclude, the computational framework we developed is based on realistic catheter shapes designed with parameter configurations which resemble clinical settings. Results showed it is well suited to investigate how mapping catheter geometry and location affect AF driver detection, therefore it is a reliable tool to design and test new mapping catheters.

scholarly journals Arrhythmogenic Effects of Genetic Mutations Affecting Potassium Channels in Human Atrial Fibrillation: A Simulation Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Rebecca Belletti ◽  
Lucia Romero ◽  
Laura Martinez-Mateu ◽  
Elizabeth M. Cherry ◽  
Flavio H. Fenton ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrium ◽  
Pulmonary Vein ◽  
Protein Structures ◽  
Spiral Wave ◽  
Ionic Currents ◽  
Patient Specific ◽  
Genetic Mutations ◽  
Asymptomatic Patients ◽  
Arrhythmogenic Substrate

Genetic mutations in genes encoding for potassium channel protein structures have been recently associated with episodes of atrial fibrillation in asymptomatic patients. The aim of this study is to investigate the potential arrhythmogenicity of three gain-of-function mutations related to atrial fibrillation—namely, KCNH2 T895M, KCNH2 T436M, and KCNE3-V17M—using modeling and simulation of the electrophysiological activity of the heart. A genetic algorithm was used to tune the parameters’ value of the original ionic currents to reproduce the alterations experimentally observed caused by the mutations. The effects on action potentials, ionic currents, and restitution properties were analyzed using versions of the Courtemanche human atrial myocyte model in different tissues: pulmonary vein, right, and left atrium. Atrial susceptibility of the tissues to spiral wave generation was also investigated studying the temporal vulnerability. The presence of the three mutations resulted in an overall more arrhythmogenic substrate. Higher current density, action potential duration shortening, and flattening of the restitution curves were the major effects of the three mutations at the single-cell level. The genetic mutations at the tissue level induced a higher temporal vulnerability to the rotor’s initiation and progression, by sustaining spiral waves that perpetuate until the end of the simulation. The mutation with the highest pro-arrhythmic effects, exhibiting the widest sustained VW and the smallest meandering rotor’s tip areas, was KCNE3-V17M. Moreover, the increased susceptibility to arrhythmias and rotor’s stability was tissue-dependent. Pulmonary vein tissues were more prone to rotor’s initiation, while in left atrium tissues rotors were more easily sustained. Re-entries were also progressively more stable in pulmonary vein tissue, followed by the left atrium, and finally the right atrium. The presence of the genetic mutations increased the susceptibility to arrhythmias by promoting the rotor’s initiation and maintenance. The study provides useful insights into the mechanisms underlying fibrillatory events caused by KCNH2 T895M, KCNH2 T436M, and KCNE3-V17M and might aid the planning of patient-specific targeted therapies.

P2843Impact of bipolar vector orientation and inter-electrode spacing on electrograms during human atrial fibrillation

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
D Linz ◽  
S Saha ◽  
R Kutieleh ◽  
K Kadhim ◽  
D Lau ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Shannon Entropy ◽  
Low Voltage ◽  
Dominant Frequency ◽  
Electrode Spacing ◽  
Peak Voltage ◽  
Vector Orientation ◽  
The Impact ◽  
Mapping Catheter ◽  
Human Atrial Fibrillation

Abstract Background In patients with atrial fibrillation (AF), local atrial bipolar electrograms (EGM) are clinically used to determine peak-to-peak voltage (Vpp), dominant frequency (DF) and Shannon Entropy (ShEn) for electroanatomical substrate characterization and substrate-based ablation. The effect of bipolar vector orientation and inter-electrode spacing on these EGM-derived measures during AF is unclear. Methods To quantify the impact of bipolar vector orientation and inter-electrode spacing, bipolar EGM (10,496 and 20,968 atrial sites, respectively) were reconstructed from unipolar EGM recorded with an array of 18 electrodes in 14 patients with persistent AF. We compared Vpp, DF and ShEn between any two adjacent bipolar vectors with a difference of 45 degree. Vpp, DF and ShEn values were ranked into different classes from highest to lowest value. To quantify the effect of inter-electrode spacing, bipolar EGM were constructed from electrodes spaced 4mm, 8mm, and 12mm apart, respectively. Results First, bipolar vector orientation significantly impacts Vpp (maximal difference: 1.341±2.169 mV vs. 0.595±0.652 mV; p<0.01) and the percentage of atrial low voltage areas (Vpp<0.05mV) (maximal difference: 62.31% vs. 32.54%). Bipolar vector orientation also influences DF (maximal difference: 8.547±2.971 Hz vs. 6.360±1.077 Hz; p<0.01) and ShEn (maximal difference: 4.898±0.488 vs. 4.120±0.650; p<0.01) measurements. Second, inter-electrode spacing affects Vppincreasing from 0.854±1.299 mV to 1.013±1.302 mV for 4mm, and 12mm, respectively (p<0.01). The percentage of atrial low voltage areas differed between 53.77% and 42.03% for 4mm and 12mm, respectively. Furthermore, inter-electrode spacing alters DF (maximal difference: 7.316±2.239 Hz vs. 7.234±2.124 Hz; p<0.01) and ShEn (maximal difference: 4.364±0.714 vs. 4.514±0.624; p<0.01) measurements. Conclusions Bipolar vector orientation and inter-electrode spacing both significantly affect bipolar EGM-derived measures that may result in significant uncertainty around the electroanatomical substrate characterization in AF patients, which should be considered in the development of future mapping catheter tools and algorithms.

scholarly journals A case report of pulmonary vein isolation with radiofrequency catheter using superior vena cava approach in patient with paroxysmal atrial fibrillation and inferior vena cava filter

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Masatoshi Narikawa ◽  
Masayoshi Kiyokuni ◽  
Junya Hosoda ◽  
Toshiyuki Ishikawa
Keyword(s):  
Atrial Fibrillation ◽  
Inferior Vena Cava ◽  
Left Atrium ◽  
Inferior Vena ◽  
Superior Vena ◽  
Vena Cava ◽  
Ivc Filter ◽  
Transseptal Puncture ◽  
Mapping Catheter ◽  
Steerable Sheath

Abstract Background Transseptal puncture and pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF) are generally performed via the inferior vena cava (IVC). However, in cases where the IVC is inaccessible, a specific strategy may be needed. Case summary An 86-year-old woman with paroxysmal AF and an IVC filter in situ was referred to our hospital for ablation therapy. An IVC filter for pulmonary embolism and deep venous thrombosis had been implanted 15 years prior, therefore we selected a transoesophageal echocardiography (TOE)-guided transseptal puncture using a superior vena cava (SVC) approach. After the single transseptal puncture, we performed fast anatomical mapping, voltage mapping by multipolar mapping catheter, and then PVI by contact force-guided radiofrequency catheter using a steerable sheath. Following the ablation, bidirectional conduction block between the four pulmonary veins and the left atrium was confirmed by both radiofrequency and mapping catheter. No complications occurred and no recurrence of AF was documented in the 12 months after the procedure. Discussion When performing a transseptal puncture during AF ablation, an SVC approach, via access through the right internal jugular vein, enables the sheath to directly approach the left atrium without angulation and improves operability of the ablation catheter. Combining the use of general anaesthesia, TOE, a steerable sheath, and contact force-guided ablation may contribute to achieving minimally invasive PVI with a single transseptal puncture via an SVC approach.

Abstract 14839: High-resolution Spatiotemporal Changes in Dominant Frequency and Structural Organization During Persistent Atrial Fibrillation

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Terrence Pong ◽  
Joy Aparicio Valenzuela ◽  
Kevin J Cyr ◽  
Cody Carlton ◽  
Sasank Sakhamuri ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
High Resolution ◽  
Structural Organization ◽  
Porcine Model ◽  
Dominant Frequency ◽  
Patient Specific ◽  
Structural Remodeling ◽  
Atrial Activity ◽  
Spatiotemporal Changes ◽  
Mapping Arrays

Introduction: Spatiotemporal differences in atrial activity are thought to contribute to the maintenance of atrial fibrillation (AF). While recent evidence has identified changes in dominant frequency (DF) during the transition from paroxysmal to persistent AF, little is known about the frequency characteristics of the epicardium during this transition. The purpose of this study was to perform high-resolution mapping of the atrial epicardium and to characterize changes in frequency activity and structural organization during the transition from paroxysmal to persistent AF. Hypothesis: In a porcine model of persistent AF, we tested the hypothesis that the epicardium undergoes spatiotemporal changes in atrial activity and structural organization during persistent AF. Methods: Paroxysmal and persistent AF was induced in adult Yorkshire swine by atrial tachypacing. Atrial morphology was segmented from magnetic resonance imaging and high-resolution patient-specific flexible mapping arrays were 3D printed to match the epicardial contours of the atria. Epicardial activation and DF mapping was performed in four paroxysmal and four persistent AF animals using personalized mapping arrays. Histological analysis was performed to determine structural differences between paroxysmal and persistent AF. Results: The left atrial epicardium was associated with a significant increase in DF between paroxysmal and persistent AF (6.5 ± 0.2 vs. 7.4 ± 0.5 Hz, P = 0.03). High-resolution spatiotemporal mapping identified organized clusters of DF during paroxysmal AF which were lost during persistent AF. The development of persistent AF led to structural remodeling with increased atrial epicardial fibrosis. The organization index (OI) significantly decreased during persistent AF in both the left atria (0.3 ± 0.03 vs. 0.2 ± 0.03, P = 0.01) and right atria (0.33 ± 0.04 vs. 0.23 ± 0.02, P = 0.02). Conclusions: In the porcine model of persistent AF, the epicardium undergoes structural remodeling with increased epicardial fibrosis, reflected by changes in atrial organization index and dominant frequency.

On-device Prior Knowledge Incorporated Learning for Personalized Atrial Fibrillation Detection

2021 ◽  
Vol 20 (5s) ◽  
pp. 1-25
Author(s):  
Zhenge Jia ◽  
Yiyu Shi ◽  
Samir Saba ◽  
Jingtong Hu
Keyword(s):  
Atrial Fibrillation ◽  
Prior Knowledge ◽  
Domain Knowledge ◽  
Fine Tuning ◽  
Cardiac Monitoring ◽  
Patient Specific ◽  
Detection Accuracy ◽  
Specific Patient ◽  
Deep Model ◽  
Tuning Strategy

Atrial Fibrillation (AF), one of the most prevalent arrhythmias, is an irregular heart-rate rhythm causing serious health problems such as stroke and heart failure. Deep learning based methods have been exploited to provide an end-to-end AF detection by automatically extracting features from Electrocardiogram (ECG) signal and achieve state-of-the-art results. However, the pre-trained models cannot adapt to each patient’s rhythm due to the high variability of rhythm characteristics among different patients. Furthermore, the deep models are prone to overfitting when fine-tuned on the limited ECG of the specific patient for personalization. In this work, we propose a prior knowledge incorporated learning method to effectively personalize the model for patient-specific AF detection and alleviate the overfitting problems. To be more specific, a prior-incorporated portion importance mechanism is proposed to enforce the network to learn to focus on the targeted portion of the ECG, following the cardiologists’ domain knowledge in recognizing AF. A prior-incorporated regularization mechanism is further devised to alleviate model overfitting during personalization by regularizing the fine-tuning process with feature priors on typical AF rhythms of the general population. The proposed personalization method embeds the well-defined prior knowledge in diagnosing AF rhythm into the personalization procedure, which improves the personalized deep model and eliminates the workload of manually adjusting parameters in conventional AF detection method. The prior knowledge incorporated personalization is feasibly and semi-automatically conducted on the edge, device of the cardiac monitoring system. We report an average AF detection accuracy of 95.3% of three deep models over patients, surpassing the pre-trained model by a large margin of 11.5% and the fine-tuning strategy by 8.6%.

Abstract 15692: Voltage Mapping in Atrial Fibrillation vs Sinus Rhythm: Results From the Mavs Study

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Carola Gianni ◽  
Jerri A Cunningham ◽  
Sanghamitra Mohanty ◽  
CHINTAN TRIVEDI ◽  
Domenico G Della Rocca ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Sinus Rhythm ◽  
Low Voltage ◽  
Lateral Wall ◽  
Posterior Wall ◽  
Anterior Wall ◽  
Inferior Wall ◽  
Voltage Mapping ◽  
First Time ◽  
Mapping Catheter

Background: Left atrial (LA) scar can be identified with bipolar voltage mapping during sinus rhythm (SR). It is not clear whether the same voltage criteria can be applied during atrial fibrillation (AF). Objective: Aim of this study was to compare voltage maps performed in the same patient both in AF and SR. Methods: Voltage mapping was performed using a 10-pole circular mapping catheter in patients with non-paroxysmal AF undergoing first time RF ablation. For descriptive purposes, the LA was divided in 6 regions: septum, posterior wall (PW), inferior wall (IW), lateral wall, anterior wall, and roof. The threshold for low voltage was <0.5 mV (with a color range setting 0.2-0.5 mV). Mild “scar” was defined as an area low voltage 5-20%, moderate 20-35% and severe as >35%. Results: 16 patients (62% persistent AF, 38% longstanding persistent AF) were included in the study. The map density was comparable during AF and SR (mean points per map 551 vs 547, paired t test P = NS). 2 patients displayed normal voltage during both AF and SR. 14 patients showed areas of low voltage during AF, which were still present during SR in 8. All patients with mild “scarring” during AF (n = 4), showed normal voltage during SR. Of the 7 patients with moderate “scarring”, 2 patients showed normal voltage during SR, while in the remaining 5 “scarring” was only mild during SR. 3 patients showed extensive “scarring” during AF, which was only moderate during SR. During AF, areas of low voltage were more commonly observed in the PW (12/14) followed by the IW (6/14) and antero-septum (4/14); while in SR, in the antero-septum (4/8), PW (3/8) and IW (3/8). Interestingly, in all patients both the PW/IW and (less dramatically) the antero-septum showed more “scarring” during AF as compared to SR. Conclusion: Areas of low voltage are more severe and diffuse during AF when compared to SR. When areas of low voltage are detected during AF, they are more commonly seen in the PW, IW and antero-septal areas.

Abstract 12471: Optimal Prediction of Atrial Fibrillation Recurrence After Ablation: A Computational Anatomy Study

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Marta Varela ◽  
Felipe Bisbal ◽  
Ernesto Zacur ◽  
Esther Guiu ◽  
Antonio Berruezo ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrial ◽  
Complete Characterization ◽  
Statistical Shape Model ◽  
Patient Specific ◽  
Shape Variation ◽  
Global Features ◽  
Linear Discriminant ◽  
Af Ablation ◽  
Statistical Shape

Background: Left atrial structural remodelling, assessed by left atrial (LA) sphericity or antero-posterior diameter, has been shown to predict recurrence after atrial fibrillation (AF) ablation. The study aimed to perform a computational shape analysis of the LA to quantitatively characterise the LA shape remodelling process and identify metrics that optimally predict recurrence. Methods: Pre-procedural bright-blood MRIs of the LA of patients undergoing AF ablation were segmented. Patient-specific smooth 3D meshes were fitted to the segmentations. A statistical shape model of the LA was created and the global features underpinning the observed shape variation extracted as principal components (PCs). PCs were optimally combined to create non-empirical atlas-based metrics using linear discriminant analysis. Meshes depicting mean and extreme recurrent and non-recurrent LA shapes were also synthetized. The capability of different metrics to predict recurrence was evaluated using the area under the ROC curve (AUC) of a leave 1 out cross validation test. Results: In total, 111 patients were included. At 12 months follow-up, LA sphericity was the best predictor of recurrence (AUC: 0.66) over novel atlas-based metrics (AUC: 0.65). At 24 months, atlas-based metrics were the best predictors of recurrence (AUC: 0.66), outperforming a combination of sphericity and volume (AUC: 0.64), sphericity alone (AUC: 0.63) and any other traditional metric. Conclusions: Novel atlas-based metrics improve the prediction of recurrence at 2 years post-AF ablation. They allow a more complete characterization of the LA shape remodelling process, for example by allowing the synthesis of recurrent and non-recurrent LA shapes, which may contribute to patient stratification for AF ablation.

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