Abstract
Background Coronary artery disease risk factors are associated with atrial fibrillation (AF) and coronary endothelial dysfunction (CED). We hypothesized that CED is associated with increased risk of incident AF among patients with chest pain and nonobstructive coronary artery disease. Methods and Results Three hundred patients with chest pain, nonobstructive coronary artery disease, and no history of AF underwent intracoronary acetylcholine infusion for evaluation of baseline epicardial (decrease in mid-left anterior descending coronary artery diameter in response to acetylcholine) and microvascular (<50% increase in coronary blood flow in response to acetylcholine) CED. Primary outcome was incident AF over a mean follow-up period of 10.5±5.5 years. Mean age was 53.3±10.8 years, and 70% were women. Baseline clinical and echocardiographic characteristics were similar between patients with CED (n=256) and those with normal endothelial function (n=44). Overall, 35 of 300 (12%) patients developed AF, among whom 34 of 35 (97%) had CED at baseline. Compared with normal endothelial function, the presence of CED was associated with 11% increased absolute risk and 5.8-fold increased relative risk of incident AF. Moreover, CED (odds ratio, 3.87; 95% CI, 1.27-47.0) and increased (>34 mL/m(2)) left atrial volume index (odds ratio, 3.87; 95% CI, 1.60-9.11) were independent predictors of incident AF. Conclusions Patients with normal coronary endothelial function, as compared with those with CED and similar AF risk factors, have significantly lower incidence of AF on long-term follow-up. The potential mechanistic link between vascular dysfunction and AF development warrants further investigation.