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Coronary artery disease (CAD) risk factors are associated with atrial fibrillation (AF) and impaired endothelial function. We hypothesized that an abnormal coronary reactivity test (Abn-CRT) is associated with AF in patients with non-obstructive CAD.
Three hundred patients with chest pain, non-obstructive CAD [<40% angiographic stenosis], and no history of AF underwent baseline CRT. Intracoronary (IC) acetylcholine (Ach) infusion was used to assess epicardial (EED) and microvascular (MED) endothelial dysfunction (decrease in mid-LAD diameter and <50% increase in coronary blood flow to Ach, respectively). Endothelial-independent microvascular dysfunction (EIMD, coronary flow reserve <2.5) was assessed using IC adenosine injection. Abn-CRT was defined as EED, MED or EIMD. Patients were followed 10.5 ±5.5 yrs for development of AF.
Mean age was 53.3±10.8 yrs, BMI 29.1±5.8 kg/mm2. Seventy percent were women, 48% had hypertension (HTN), 56% hyperlipidemia (HLD), 9% diabetes (DM), and 6% were smokers. Eighty-five percent had baseline Abn-CRT, but their demographics were similar to patients with normal CRT. Overall, 35 (11.7%) patients developed AF, among which 34 (97%) had baseline Abn-CRT (Fig. A). Abn-CRT was associated with 5.8-fold increase in AF risk (Fig. B), p=0.02 adjusted for age, sex, BMI, HTN, HLD, DM, smoking and obstructive sleep apnea.
Abn-CRT is a predictor of incident AF, suggesting that AF is a vascular disease associated with coronary endothelial and microvascular dysfunction.