Larger left atrial size and reduced anteroposterior diameter were linked to increased rotational propagation patterns in persistent atrial fibrillation.
Statistical shape and appearance modeling demonstrates that left atrial dilation and reduced anteroposterior diameter are associated with increased rotational propagation patterns in persistent atrial fibrillation.
Abstract Background Atrial fibrillation (AF) arises from a complex interplay of structural and electrical remodelling. However, the relationship between left atrial (LA) geometry and AF wavefront dynamics remains poorly defined. Purpose This study applied Statistical Shape and Appearance Modelling (SSAM) to quantitatively characterise LA geometric features and their association with rotational propagation patterns in persistent AF. Methods Thirty-five patients with persistent AF underwent de novo ablation guided by charge density mapping. High fidelity three-dimensional LA reconstructions were generated using intra-chamber ultrasound. Non-contact intra-chamber voltage measurements were recorded during 20 seconds of AF, with rotational propagation patterns defined as wavefronts rotating more than 270 degrees around a fixed point and quantified as occurrences per second 1. For SSAM, each LA was represented by 512 correspondence points using a particle-based modelling approach 2. A nearest-neighbour algorithm assigned values for rotational propagation pattern frequency to correspondence points. Each LA was then represented by a single point in high-dimensional feature space, with principal component analysis identifying major modes of variation. Deformation of the mean along these modes facilitated visualisation and interpretation. Results Patient demographics and clinical characteristics are presented in the Table. Mean age was 62±12 years, 26 (74%) were male, mean BMI was 29±7.2 kg/m2, and median CHA2DS2-VASc score was 2 (IQR: 1-3). Mean LA volume was 162.9±33.5ml. The first three modes of variation accounted for 68% of variance (Figure). Mode 1 (40% variance) captured global LA size variation, with larger atria exhibiting more widespread rotational propagation. Mode 2 (17% variance) reflected reduced anteroposterior diameter, which was associated with increased rotational propagation along the anterior and inferior walls. Mode 3 (11% variance) described a combination of reduced anteroposterior diameter and posterior wall flattening, correlating with increased rotational propagation in the anterior and inferoposterior LA regions. Conclusion By integrating geometric and functional data, SSAM reveals the relationship between LA geometry and rotational propagation patterns. These propagation patterns are believed to arise as a functional consequence of pathophysiological substrates linked to negative remodelling, and their association with atrial dilation aligns with the multiple wavelet hypothesis. Notably, our model also identifies a link between reduced anteroposterior diameter and rotational propagation patterns, suggesting compressive effects from adjacent thoracic structures such as the spine and aorta may influence structural and electrical remodelling. Such SSAM-derived insights could enhance in silico AF simulations and inform ablation strategies by identifying structurally predisposed regions for targeted intervention.
Sharp et al. (2025) studied this question. Larger left atrial size and reduced anteroposterior diameter were linked to increased rotational propagation patterns in persistent atrial fibrillation.