Atrial fibrillation substrate and impaired left atrial function: a cardiac MRI study

Area of Science:

• Cardiovascular Imaging
• Cardiac Electrophysiology
• Medical Imaging Analysis

Background:

• Atrial fibrillation (AF) is associated with structural and fibrotic remodeling of the left atrium (LA).
• Epicardial adipose tissue (EAT) is increasingly implicated in atrial electrical remodeling and AF pathogenesis.
• Understanding the interplay between LA fibrosis, EAT, and LA function is crucial for AF management.

Purpose of the Study:

• To investigate the association between LA fibrosis and EAT with LA strain and function.
• To utilize cardiac magnetic resonance (CMR) imaging for quantitative assessment in AF patients.

Main Methods:

• One hundred one AF patients underwent pre-ablation CMR in sinus rhythm.
• LA fibrosis assessed via late gadolinium enhancement; LA EAT quantified using Dixon sequences.
• Feature tracking analyzed global longitudinal strain (GLS) components; LA emptying fraction and volume measured from cine sequences.

Main Results:

• LA fibrosis negatively correlated with all three GLS components (GLRS, GLCdS, GLCtS) and LA emptying fraction.
• LA EAT showed a negative correlation with GLCdS and was not significantly correlated with LA emptying fraction.
• Both LA fibrosis and EAT were positively correlated with increased LA volume.

Conclusions:

• LA fibrosis and EAT are significantly associated with impaired LA function, as evidenced by strain analysis.
• These findings underscore the role of LA fibrosis and EAT as key contributors to the AF substrate.
• CMR imaging provides valuable insights into the structural and functional consequences of LA fibrosis and EAT in AF.