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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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Related in: MedlinePlus

Sinus rhythm propagation under physiological and remodeling conditions.Propagation of the last sinus beat applied for both physiological (A) and remodeling (B) conditions. The color scale represents the range of AP values (mV). The depolarizing fronts can be identified by the red color.
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pone-0050883-g004: Sinus rhythm propagation under physiological and remodeling conditions.Propagation of the last sinus beat applied for both physiological (A) and remodeling (B) conditions. The color scale represents the range of AP values (mV). The depolarizing fronts can be identified by the red color.

Mentions: An atrial propagation pattern in sinus rhythm was simulated in the model by applying a periodic stimulus (10 beats) at a basic cycle length of 1000 ms in the anatomic location of the SAN. Figure 4 shows different snapshots of the propagation of the last beat applied for both physiological (Figure 4A) and remodeling (Figure 4B) conditions. A delayed activation front in the remodeled atria can be observed. In Figure 4, it is possible to note how the stimulus applied in the SAN region caused the initiation of a propagating wavefront that quickly spread to the ICV favored by the high conductivity of the CT arch. The anisotropy of the CT caused an almost triangular wavefront (see snapshots at 36 ms in Figures 4A and 4B). The depolarizing wave reached the BB after 22 ms and propagated to the anterior septal portion of the LA through interatrial BB, inducing the first activation of the LA at 46 ms (in normal atria) and 54 ms (in remodeled atria) after the SAN activation. Thereafter, at 53 ms and 62 ms from the SAN activation for normal and remodeled atria, respectively, the interatrial connection at the limbus of the FO contributed to left atrial septal activation. The activation wave also propagated to LA through the third interatrial connection, the RA-CS-LA pathway, at 87 ms and 98 ms, respectively, and the first LA inferior wall activation was observed at 117 ms and 132 ms for normal and remodeled atria, respectively.


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)

Sinus rhythm propagation under physiological and remodeling conditions.Propagation of the last sinus beat applied for both physiological (A) and remodeling (B) conditions. The color scale represents the range of AP values (mV). The depolarizing fronts can be identified by the red color.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0050883-g004: Sinus rhythm propagation under physiological and remodeling conditions.Propagation of the last sinus beat applied for both physiological (A) and remodeling (B) conditions. The color scale represents the range of AP values (mV). The depolarizing fronts can be identified by the red color.
Mentions: An atrial propagation pattern in sinus rhythm was simulated in the model by applying a periodic stimulus (10 beats) at a basic cycle length of 1000 ms in the anatomic location of the SAN. Figure 4 shows different snapshots of the propagation of the last beat applied for both physiological (Figure 4A) and remodeling (Figure 4B) conditions. A delayed activation front in the remodeled atria can be observed. In Figure 4, it is possible to note how the stimulus applied in the SAN region caused the initiation of a propagating wavefront that quickly spread to the ICV favored by the high conductivity of the CT arch. The anisotropy of the CT caused an almost triangular wavefront (see snapshots at 36 ms in Figures 4A and 4B). The depolarizing wave reached the BB after 22 ms and propagated to the anterior septal portion of the LA through interatrial BB, inducing the first activation of the LA at 46 ms (in normal atria) and 54 ms (in remodeled atria) after the SAN activation. Thereafter, at 53 ms and 62 ms from the SAN activation for normal and remodeled atria, respectively, the interatrial connection at the limbus of the FO contributed to left atrial septal activation. The activation wave also propagated to LA through the third interatrial connection, the RA-CS-LA pathway, at 87 ms and 98 ms, respectively, and the first LA inferior wall activation was observed at 117 ms and 132 ms for normal and remodeled atria, respectively.

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