High-resolution spatiotemporal changes in dominant frequency and structural organization during persistent atrial...

Area of Science:

• Electrophysiology
• Cardiovascular Research
• Medical Imaging

Background:

• Limited understanding of epicardial frequency characteristics during the transition from paroxysmal to persistent atrial fibrillation (AF).
• Challenges in accurately identifying high dominant frequency (DF) areas due to limited spatial resolution in previous studies.
• Advancements in electrode array technology offer high spatiotemporal resolution for characterizing AF-related changes.

Purpose of the Study:

• To analyze changes in frequency activity and structural organization over time in persistent atrial fibrillation (AF).
• To investigate the transition from paroxysmal to persistent AF using high-resolution mapping.
• To correlate electrophysiological findings with structural changes like fibrosis.

Main Methods:

• Atrial tachypacing was used to induce AF in adult Yorkshire swine.
• Personalized mapping arrays were employed for Dominant Frequency (DF) mapping.
• Histological analysis and late gadolinium-enhanced magnetic resonance imaging (MRI) were performed to assess fibrosis and structural differences.

Main Results:

• A significant increase in left atrial epicardial DF was observed in persistent AF (7.4 ± 0.5 Hz) compared to paroxysmal AF (6.5 ± 0.2 Hz).
• The organization index (OI) significantly decreased in both left and right atria during persistent AF.
• MRI revealed increased extracellular volume (ECV) in persistent AF, and histological analysis confirmed increased fibrosis and disorganized myocardial fibers.

Conclusions:

• Persistent AF in the porcine model is characterized by altered tissue organization and increased fibrosis.
• High-resolution flexible electrode arrays can effectively capture alterations in frequency activity and organization index during AF progression.
• These findings provide valuable insights into the electrophysiological and structural remodeling associated with persistent AF.