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A three-dimensional human atrial model with fiber orientation. Electrograms and arrhythmic activation patterns relationship.

Tobón C, Ruiz-Villa CA, Heidenreich E, Romero L, Hornero F, Saiz J - PLoS ONE (2013)

Bottom Line: The model includes a realistic geometry with fiber orientation, anisotropic conductivity and electrophysiological heterogeneity.We simulated different tachyarrhythmic episodes applying both transient and continuous ectopic activity.Our results also show: (1) electrograms with potentials without negative deflection related to spiral or curved wavefronts that pass over the recording point and move away, (2) potentials with a much greater proportion of positive deflection than negative in areas of wave collisions, (3) double potentials related with wave fragmentations or blocking lines and (4) fragmented electrograms associated with pivot points.

View Article: PubMed Central - PubMed

Affiliation: Instituto Interuniversitario de Investigación en Bioingeniería y Tecnología Orientada al Ser Humano (I3BH), Universitat Politècnica de València, Valencia, Spain.

ABSTRACT
The most common sustained cardiac arrhythmias in humans are atrial tachyarrhythmias, mainly atrial fibrillation. Areas of complex fractionated atrial electrograms and high dominant frequency have been proposed as critical regions for maintaining atrial fibrillation; however, there is a paucity of data on the relationship between the characteristics of electrograms and the propagation pattern underlying them. In this study, a realistic 3D computer model of the human atria has been developed to investigate this relationship. The model includes a realistic geometry with fiber orientation, anisotropic conductivity and electrophysiological heterogeneity. We simulated different tachyarrhythmic episodes applying both transient and continuous ectopic activity. Electrograms and their dominant frequency and organization index values were calculated over the entire atrial surface. Our simulations show electrograms with simple potentials, with little or no cycle length variations, narrow frequency peaks and high organization index values during stable and regular activity as the observed in atrial flutter, atrial tachycardia (except in areas of conduction block) and in areas closer to ectopic activity during focal atrial fibrillation. By contrast, cycle length variations and polymorphic electrograms with single, double and fragmented potentials were observed in areas of irregular and unstable activity during atrial fibrillation episodes. Our results also show: (1) electrograms with potentials without negative deflection related to spiral or curved wavefronts that pass over the recording point and move away, (2) potentials with a much greater proportion of positive deflection than negative in areas of wave collisions, (3) double potentials related with wave fragmentations or blocking lines and (4) fragmented electrograms associated with pivot points. Our model is the first human atrial model with realistic fiber orientation used to investigate the relationship between different atrial arrhythmic propagation patterns and the electrograms observed at more than 43000 points on the atrial surface.

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AP for different atrial areas and APD90 restitution curve for AWM under physiological and remodeling conditions.AP time courses for the considered atrial cellular models (CT, PM, APG, AVR and AWM) under physiological (A) and remodeling conditions (B). APD90 restitution curve for AWM under physiological (control) and remodeling conditions (C).
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pone-0050883-g003: AP for different atrial areas and APD90 restitution curve for AWM under physiological and remodeling conditions.AP time courses for the considered atrial cellular models (CT, PM, APG, AVR and AWM) under physiological (A) and remodeling conditions (B). APD90 restitution curve for AWM under physiological (control) and remodeling conditions (C).

Mentions: Figure 3 depicts the APs for the different atrial cellular models considered, under both physiological (control) and remodeling conditions (Figure 3A and 3B, respectively). In these figures, we present the last AP obtained when a train of 10 stimuli at a basic cycle length of 1000 ms was applied. The corresponding APD90 (APD to 90% of repolarization) values for the different atrial cells (both for control and remodeling conditions) are shown in Table 2. Under control conditions, APD90 showed high values (ranged from 180 ms to 307 ms) in agreement with experimental data [7], [36] and a great APD dispersion was observed (APD90max – APD90min  = 127 ms). By contrast, under remodeling conditions, the APD decreased (ranged from 56 ms to 92 ms) and a smaller APD dispersion was observed (APD90max – APD90min  = 36 ms). Figure 3C shows the APD90 restitution curve for control and remodeled cells when the coupling interval (CI) between pulses is increased. Remodeling conditions not only induce a shortening in the APD90 but also reduce the frequency dependent adaptation of APD90.


A three-dimensional human atrial model with fiber orientation. Electrograms and arrhythmic activation patterns relationship.

Tobón C, Ruiz-Villa CA, Heidenreich E, Romero L, Hornero F, Saiz J - PLoS ONE (2013)

AP for different atrial areas and APD90 restitution curve for AWM under physiological and remodeling conditions.AP time courses for the considered atrial cellular models (CT, PM, APG, AVR and AWM) under physiological (A) and remodeling conditions (B). APD90 restitution curve for AWM under physiological (control) and remodeling conditions (C).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3569461&req=5

pone-0050883-g003: AP for different atrial areas and APD90 restitution curve for AWM under physiological and remodeling conditions.AP time courses for the considered atrial cellular models (CT, PM, APG, AVR and AWM) under physiological (A) and remodeling conditions (B). APD90 restitution curve for AWM under physiological (control) and remodeling conditions (C).
Mentions: Figure 3 depicts the APs for the different atrial cellular models considered, under both physiological (control) and remodeling conditions (Figure 3A and 3B, respectively). In these figures, we present the last AP obtained when a train of 10 stimuli at a basic cycle length of 1000 ms was applied. The corresponding APD90 (APD to 90% of repolarization) values for the different atrial cells (both for control and remodeling conditions) are shown in Table 2. Under control conditions, APD90 showed high values (ranged from 180 ms to 307 ms) in agreement with experimental data [7], [36] and a great APD dispersion was observed (APD90max – APD90min  = 127 ms). By contrast, under remodeling conditions, the APD decreased (ranged from 56 ms to 92 ms) and a smaller APD dispersion was observed (APD90max – APD90min  = 36 ms). Figure 3C shows the APD90 restitution curve for control and remodeled cells when the coupling interval (CI) between pulses is increased. Remodeling conditions not only induce a shortening in the APD90 but also reduce the frequency dependent adaptation of APD90.

Bottom Line: The model includes a realistic geometry with fiber orientation, anisotropic conductivity and electrophysiological heterogeneity.We simulated different tachyarrhythmic episodes applying both transient and continuous ectopic activity.Our results also show: (1) electrograms with potentials without negative deflection related to spiral or curved wavefronts that pass over the recording point and move away, (2) potentials with a much greater proportion of positive deflection than negative in areas of wave collisions, (3) double potentials related with wave fragmentations or blocking lines and (4) fragmented electrograms associated with pivot points.

View Article: PubMed Central - PubMed

Affiliation: Instituto Interuniversitario de Investigación en Bioingeniería y Tecnología Orientada al Ser Humano (I3BH), Universitat Politècnica de València, Valencia, Spain.

ABSTRACT
The most common sustained cardiac arrhythmias in humans are atrial tachyarrhythmias, mainly atrial fibrillation. Areas of complex fractionated atrial electrograms and high dominant frequency have been proposed as critical regions for maintaining atrial fibrillation; however, there is a paucity of data on the relationship between the characteristics of electrograms and the propagation pattern underlying them. In this study, a realistic 3D computer model of the human atria has been developed to investigate this relationship. The model includes a realistic geometry with fiber orientation, anisotropic conductivity and electrophysiological heterogeneity. We simulated different tachyarrhythmic episodes applying both transient and continuous ectopic activity. Electrograms and their dominant frequency and organization index values were calculated over the entire atrial surface. Our simulations show electrograms with simple potentials, with little or no cycle length variations, narrow frequency peaks and high organization index values during stable and regular activity as the observed in atrial flutter, atrial tachycardia (except in areas of conduction block) and in areas closer to ectopic activity during focal atrial fibrillation. By contrast, cycle length variations and polymorphic electrograms with single, double and fragmented potentials were observed in areas of irregular and unstable activity during atrial fibrillation episodes. Our results also show: (1) electrograms with potentials without negative deflection related to spiral or curved wavefronts that pass over the recording point and move away, (2) potentials with a much greater proportion of positive deflection than negative in areas of wave collisions, (3) double potentials related with wave fragmentations or blocking lines and (4) fragmented electrograms associated with pivot points. Our model is the first human atrial model with realistic fiber orientation used to investigate the relationship between different atrial arrhythmic propagation patterns and the electrograms observed at more than 43000 points on the atrial surface.

Show MeSH
Related in: MedlinePlus