Corban MT, Godo S, Burczak DR, et al. - Researchers investigated if there exists an association of coronary endothelial dysfunction (CED) with increased risk of incident atrial fibrillation (AF) in patients with chest pain and nonobstructive coronary artery disease. This analysis involved 300 patients with no history of AF. The participants were asked to undergo intracoronary acetylcholine infusion for the assessment of baseline epicardial (defined as reduction in mid–left anterior descending coronary artery diameter in response to acetylcholine) and microvascular (defined as < 50% rise in coronary blood flow in response to acetylcholine) CED. Incident AF during a mean follow‐up of 10.5 ± 5.5 years was the primary outcome. Findings revealed significantly lower incidence of AF, on long‐term follow‐up, in patients exhibiting normal coronary endothelial function vs those with CED and similar AF risk factors. The identified independent predictors of incident AF were: CED and increased (>34 mL/m²) left atrial volume index.