Impaired left atrial reservoir and conduit strain in patients with atrial fibrillation and extensive fibrosis

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Atrial fibrillation (AF) is associated with profound structural and functional changes in the atria. Timely interventions may decelerate and perhaps reverse this pathophysiologic process and improve clinical outcome. In this regard, detailed characterization of the atrial remodeling process, and understanding of the interplay between structural remodeling and function is essential. Purpose In the present study, we investigated the association between left atrial (LA) phasic function and the extent of LA fibrosis using advanced cardiovascular magnetic resonance (CMR) imaging techniques, including 3-dimensional (3D) late gadolinium enhancement (LGE) and Feature Tracking. Methods Patients with paroxysmal and persistent AF (n = 93) underwent CMR in sinus rhythm. LA global reservoir strain, conduit strain and contractile strain were derived from cine CMR images using Feature Tracking. The extent of LA fibrosis was assessed from 3D LGE images. Healthy volunteers underwent CMR and served as controls (n = 19). Results Significantly lower reservoir strain, conduit strain and contractile strain were found in AF patients, as compared to controls (-15.7 ± 3.9% vs. -21.1 ± 3.6% P < 0.001, -8.6 ± 2.9% vs. -12.6 ± 2.5% P < 0.001 and -7.1 ± 2.4% vs. -8.6 ± 2.2% P = 0.02, respectively) (Figure A, B, C). Patients with a high degree of LA fibrosis (dichotomized by the median value) had lower reservoir strain and conduit strain compared to patients with a low degree of LA fibrosis (-14.7 ± 4.0% vs. -16.8 ± 3.5%, P = 0.02 and -7.7 ± 2.7% vs. -9.5 ± 2.9%, P < 0.01, respectively). In contrast, no difference was found for LA contractile strain (-7.0 ± 2.3% vs. -7.3 ± 2.5%, P = 0.62) (Figure D, E, F). Conclusions This study shows impaired LA reservoir and conduit strain in AF patients with extensive atrial fibrosis. Of interest, LA contractile function was largely unaffected. Future studies are required to study the biologic nature of this association and possible therapeutic implications. Abstract Figure.