Limits...
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.

Show MeSH

Related in: MedlinePlus

AF episodes. Snapshots, APs, EGM and spectral analysis in selected spoints.(A) AF triggered by a transient ectopic focus and (B) AF triggered by a continuous ectopic focus, both in the ostium of the RPV. The color scale represents the range of values of the AP in mV. The depolarizing front is identified by the red color. The black arrows indicate the direction of the wavefronts and the dash line shows a blocking line. AP time-courses of selected sites (indicated in the snapshots) are showed at left, down to the snapshots. The corresponding EGM and their spectral analysis showing DF and OI values are shown at the right. In (A): + indicates AP and single potential with only a long-lasting negative deflection (snapshot at 2160 ms), • indicates AP and single potential with positive deflection greater than negative (snapshot at 2355 ms), ▪ indicates AP and potential with a small additional positive deflection (snapshot at 3220 ms) and * indicates AP and CFAE (snapshot at 8675 ms). In (B): x indicates AP and potential with deviations from the baseline, CFAE, at site 1 (snapshots at 4545 ms and 4650 ms), □ indicates AP and potentials with only negative deflections at site 2 (snapshot at 7625 ms), and ○ indicates AP and double potentials at site 3 (snapshots at 7625 ms and 7670 ms).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3569461&req=5

pone-0050883-g006: AF episodes. Snapshots, APs, EGM and spectral analysis in selected spoints.(A) AF triggered by a transient ectopic focus and (B) AF triggered by a continuous ectopic focus, both in the ostium of the RPV. The color scale represents the range of values of the AP in mV. The depolarizing front is identified by the red color. The black arrows indicate the direction of the wavefronts and the dash line shows a blocking line. AP time-courses of selected sites (indicated in the snapshots) are showed at left, down to the snapshots. The corresponding EGM and their spectral analysis showing DF and OI values are shown at the right. In (A): + indicates AP and single potential with only a long-lasting negative deflection (snapshot at 2160 ms), • indicates AP and single potential with positive deflection greater than negative (snapshot at 2355 ms), ▪ indicates AP and potential with a small additional positive deflection (snapshot at 3220 ms) and * indicates AP and CFAE (snapshot at 8675 ms). In (B): x indicates AP and potential with deviations from the baseline, CFAE, at site 1 (snapshots at 4545 ms and 4650 ms), □ indicates AP and potentials with only negative deflections at site 2 (snapshot at 7625 ms), and ○ indicates AP and double potentials at site 3 (snapshots at 7625 ms and 7670 ms).

Mentions: Figure 6 shows two AF episodes triggered by an ectopic focus placed in the ostium of the RPV. In the first case, a train of six ectopic beats (CL = 130 ms) provoked an AF episode that was maintained by different reentrant mechanisms (see snapshots in Figure 6A). Indeed, rotors, figure of eight reentries, macrorreentries, fragmentations and wavefront collisions were observed in both atria (see video S3 in the Supporting Information). This irregular activity caused the appearance of electrotonic APs and irregular APs in different areas and at different times (see APs at sites 2 and 3 in Figure 6A).


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)

AF episodes. Snapshots, APs, EGM and spectral analysis in selected spoints.(A) AF triggered by a transient ectopic focus and (B) AF triggered by a continuous ectopic focus, both in the ostium of the RPV. The color scale represents the range of values of the AP in mV. The depolarizing front is identified by the red color. The black arrows indicate the direction of the wavefronts and the dash line shows a blocking line. AP time-courses of selected sites (indicated in the snapshots) are showed at left, down to the snapshots. The corresponding EGM and their spectral analysis showing DF and OI values are shown at the right. In (A): + indicates AP and single potential with only a long-lasting negative deflection (snapshot at 2160 ms), • indicates AP and single potential with positive deflection greater than negative (snapshot at 2355 ms), ▪ indicates AP and potential with a small additional positive deflection (snapshot at 3220 ms) and * indicates AP and CFAE (snapshot at 8675 ms). In (B): x indicates AP and potential with deviations from the baseline, CFAE, at site 1 (snapshots at 4545 ms and 4650 ms), □ indicates AP and potentials with only negative deflections at site 2 (snapshot at 7625 ms), and ○ indicates AP and double potentials at site 3 (snapshots at 7625 ms and 7670 ms).
© Copyright Policy
Related In: Results  -  Collection

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

pone-0050883-g006: AF episodes. Snapshots, APs, EGM and spectral analysis in selected spoints.(A) AF triggered by a transient ectopic focus and (B) AF triggered by a continuous ectopic focus, both in the ostium of the RPV. The color scale represents the range of values of the AP in mV. The depolarizing front is identified by the red color. The black arrows indicate the direction of the wavefronts and the dash line shows a blocking line. AP time-courses of selected sites (indicated in the snapshots) are showed at left, down to the snapshots. The corresponding EGM and their spectral analysis showing DF and OI values are shown at the right. In (A): + indicates AP and single potential with only a long-lasting negative deflection (snapshot at 2160 ms), • indicates AP and single potential with positive deflection greater than negative (snapshot at 2355 ms), ▪ indicates AP and potential with a small additional positive deflection (snapshot at 3220 ms) and * indicates AP and CFAE (snapshot at 8675 ms). In (B): x indicates AP and potential with deviations from the baseline, CFAE, at site 1 (snapshots at 4545 ms and 4650 ms), □ indicates AP and potentials with only negative deflections at site 2 (snapshot at 7625 ms), and ○ indicates AP and double potentials at site 3 (snapshots at 7625 ms and 7670 ms).
Mentions: Figure 6 shows two AF episodes triggered by an ectopic focus placed in the ostium of the RPV. In the first case, a train of six ectopic beats (CL = 130 ms) provoked an AF episode that was maintained by different reentrant mechanisms (see snapshots in Figure 6A). Indeed, rotors, figure of eight reentries, macrorreentries, fragmentations and wavefront collisions were observed in both atria (see video S3 in the Supporting Information). This irregular activity caused the appearance of electrotonic APs and irregular APs in different areas and at different times (see APs at sites 2 and 3 in Figure 6A).

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