Myocardial Oxygen Extraction Is Associated with Reduced Quality of Life and Impaired Strain in AF

Abstract 2303032, presented at Western Atrial Fibrillation Symposium 2026

Atrial fibrillation (AF) is associated with reduced quality of life (QoL) and increased symptom burden, yet the mechanistic basis of patient-reported outcomes remains poorly understood. We examined whether abnormal myocardial mechanics and increased oxygen extraction in AF are associated with reduced QoL measures.Patients undergoing AF ablation underwent coronary sinus and arterial blood sampling to quantify myocardial oxygen extraction. QoL was assessed using the Atrial Fibrillation Severity Scale (AFSS), which integrates measures of global well-being, AF burden, and symptom severity score. Left atrial and ventricular functions were quantified using cardiac magnetic resonance imaging, which included reservoir, conduit, and booster pump strain, along with ventricular global longitudinal, circumferential, and radial strain (Panel A). We stratified our patient cohort into two groups based on a median oxygen extraction of 9.27 mL of oxygen/dL of blood (Panel B).Fifty AF patients were recruited. The median oxygen extraction was 9.27 mL of O2/dL of blood (7.75 – 10.88). Higher extraction was strongly correlated with worse global well-being (r = -0.753; P< 0.0001), greater AF burden (r = 0.705; P< 0.001), and higher AF symptom score (r = 0.64; P< 0.001) (Panel C). Patients with increased extraction demonstrated significantly impaired LA booster pump strain (2.68 ± 1.39% vs. 4.96 ± 2.51%; P=0.002) and reduced ventricular GLS (-16.83 ± 4.07% vs. -16.83 ± 4.07%; P=0.004) (Panel B). Using multivariable regression models, decreased atrial booster pump function and reduced GLS independently predicted myocardial oxygen extraction (B= -0.429; P=0.001 and B= 0.259 mL of O2/dL of blood; P= 0.004) after adjusting for rhythm status and HR.Increased myocardial oxygen extraction in AF patients is associated with worse AFSS QOL scores and worse atrial and ventricular mechanics, including diminished booster pump function and reduced ventricular GLS. Further studies to delineate the determinants of reduced myocardial strain and higher oxygen requirements are needed to clarify the physiologic link between myocardial dysfunction, myocardial oxygen extraction, and QoL in AF.