Electrophysiological substrate for a dominant reentrant source during atrial fibrillation

Area of Science:

• Cardiac Electrophysiology
• Computational Biology
• Medical Physics

Background:

• Atrial fibrillation (AF) is linked to differing action potential (AP) properties between the left atrium (LA) and right atrium (RA).
• Tissue heterogeneity is hypothesized to play a role in maintaining reentrant sources during AF.

Purpose of the Study:

• To investigate the role of atrial tissue heterogeneity in the global interaction of reentrant spiral waves.
• To model the influence of differing LA and RA AP properties on atrial excitation patterns.

Main Methods:

• Incorporation of single LA and RA cell AP models into a 2D atrial tissue model.
• Simulation of intra- and interatrial conduction pathways.
• Analysis of reentrant spiral wave dynamics and excitation patterns.

Main Results:

• Shorter AP refractoriness in the LA was observed compared to the RA.
• This shorter refractoriness resulted in a shorter spiral rotation period in the LA.
• LA reentry was found to dominate the overall atrial excitation patterns in the simulations.

Conclusions:

• Atrial tissue heterogeneity, specifically shorter LA refractoriness, significantly impacts reentrant wave dynamics.
• The dominance of LA reentry suggests a key mechanism contributing to atrial fibrillation maintenance.
• Computational modeling provides insights into the electrophysiological basis of atrial arrhythmias.