Regional heterogeneity in left atrial stiffness impacts passive deformation in a cohort of patient-specific models

2025-10-21

AI Summary

The biomechanical mechanisms underlying left atrial (LA) dysfunction in atrial fibrillation (AF) remain poorly understood, particularly regarding the quantitative role of regional myocardial stiffness heterogeneity. To address this, we developed a patient-specific LA biomechanical model reconstructed from clinical CT imaging, integrating regionally calibrated material parameters with dynamic, image-derived deformation data for model validation and refinement. Our analysis—first to quantitatively isolate regional stiffness effects—demonstrates that spatially varying wall stiffness is the dominant determinant of passive LA deformation, exerting significantly greater influence than anatomical factors such as wall thickness or adipose volume. The model achieves high fidelity: mean geometric error of ±0.90 mm in static deformation and transient response deviation ≤±0.38 mm/unit time, successfully recapitulating clinically observed dynamics. This work establishes a novel mechanistic framework for AF-associated LA functional remodeling and introduces a generalizable paradigm for personalized atrial modeling.

Technology Category

• Machine Learning: Calibration & Uncertainty Quantification
• Cognitive Modeling & Cognitive Systems: Affective Computing
• Reasoning under Uncertainty: Relational Probabilistic Models

Application Category

• User Modeling, Personalization and Recommendation: User model development and evaluation
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Search and Retrieval-Augmented AI: Web evaluation methodologies and metrics

Abstract

The deformation of the left atrium (LA), or its biomechanical function, is closely linked to the health of this cardiac chamber. In atrial fibrillation (AF), atrial biomechanics are significantly altered but the underlying cause of this change is not always clear. Patient-specific models of the LA that replicate patient atrial motion can allow us to understand how factors such as atrial anatomy, myocardial stiffness and physiological constraints are linked to atrial biomechanics. We created patient-specific LA models from CT images. We fitted regional model stiffness to peak CT-derived deformation during the LA reservoir phase ($pm0.90$ mm) and used the CT deformation transients through the reservoir and conduit phase for model validation (deformation transients fell within $pm0.38$ mm per unit time of targets). We found that myocardial stiffness varies regionally across the LA. The regional stiffness values were significant factors contributing to regional physiological LA deformation ($p=0.023$) while features of LA anatomy, including regional wall thickness and adipose volume, were less important. These findings provide insight into the underlying causes of altered LA biomechanics in AF.

Problem

• Investigating how regional left atrial stiffness affects passive deformation
• Understanding altered atrial biomechanics in atrial fibrillation patients
• Determining factors influencing left atrial deformation beyond anatomy

Innovation

• Created patient-specific left atrial models from CT
• Fitted regional stiffness to CT-derived deformation data
• Validated models using deformation transients through cardiac phases