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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

3D model of human atria.Frontal (A) and dorsal (B) views of the 3D model of human atria. Colored areas show regions with different conductivity and/or electrophysiological heterogeneity.
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pone-0050883-g001: 3D model of human atria.Frontal (A) and dorsal (B) views of the 3D model of human atria. Colored areas show regions with different conductivity and/or electrophysiological heterogeneity.

Mentions: An anatomically realistic 3D model of human atria that includes fiber orientation was developed. Our model comprises the following main anatomical structures: left atrium (LA) and right atrium (RA), twenty pectinate muscles (PM) in the RA free wall, the fossa ovalis (FO) in the septum with its limbus, Bachmann's bundle (BB), the crista terminalis (CT), left and right appendages (LAPG and RAPG), left and right pulmonary veins (LPV and RPV), superior and inferior caval veins (SCV and ICV), the isthmus of RA, atrioventricular rings (AVR) and the coronary sinus (CS). The sinoatrial node (SAN) is situated near the ostium of the SCV. The CT layer originates next to the SAN and crosses the RA towards the ICV while the BB starts in a region next to the SCV and extends through the LA. The CS starts in the RA and extends along the posterior atrioventricular sulcus. The model also includes three different pathways for the inter-atrial conduction of electrical propagation: the BB, the limbus of the FO and discrete sites of the CS. Figure 1 shows the frontal (Figure 1A) and dorsal (Figure 1B) views of the model.


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)

3D model of human atria.Frontal (A) and dorsal (B) views of the 3D model of human atria. Colored areas show regions with different conductivity and/or electrophysiological heterogeneity.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0050883-g001: 3D model of human atria.Frontal (A) and dorsal (B) views of the 3D model of human atria. Colored areas show regions with different conductivity and/or electrophysiological heterogeneity.
Mentions: An anatomically realistic 3D model of human atria that includes fiber orientation was developed. Our model comprises the following main anatomical structures: left atrium (LA) and right atrium (RA), twenty pectinate muscles (PM) in the RA free wall, the fossa ovalis (FO) in the septum with its limbus, Bachmann's bundle (BB), the crista terminalis (CT), left and right appendages (LAPG and RAPG), left and right pulmonary veins (LPV and RPV), superior and inferior caval veins (SCV and ICV), the isthmus of RA, atrioventricular rings (AVR) and the coronary sinus (CS). The sinoatrial node (SAN) is situated near the ostium of the SCV. The CT layer originates next to the SAN and crosses the RA towards the ICV while the BB starts in a region next to the SCV and extends through the LA. The CS starts in the RA and extends along the posterior atrioventricular sulcus. The model also includes three different pathways for the inter-atrial conduction of electrical propagation: the BB, the limbus of the FO and discrete sites of the CS. Figure 1 shows the frontal (Figure 1A) and dorsal (Figure 1B) views of the model.

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