Proximal Occlusion in the Right Coronary Artery Involving the Atrial Branch as a Strong Predictor of New-Onset Atrial Fibrillation in Acute Myocardial Infarction.

Although atrial ischemic damage is an atrial fibrillation (AF) risk factor, the impact of atrial branches' occlusion on AF development after acute myocardial infarction (AMI) is unclear. Therefore, this study's purpose was to identify predictors of new-onset AF with regard to atrial branches' occlusion. We retrospectively analyzed the AMI database at our single center. Consecutive patients with AMI from June 2011 to May 2017 were enrolled. Exclusion criteria were prior AF before AMI, hemodialysis, and follow-up of < 30 days. The study enrolled 204 consecutive patients (follow-up, 543 ± 469 days; age, 66 ± 12 years; male sex, 77%). All patients underwent primary percutaneous coronary intervention. Thirty-six patients (18%) had new-onset AF in the hospital after AMI. The Killip classification ≥ 3 (41% versus 7%, P < 0.001), ejection fraction ≤ 35% (19% versus 5%, P = 0.014), ischemic occlusion of atrial branches (58% versus 28%, P < 0.001), and ischemic occlusion of atrial branches originating from the right coronary artery (52% versus 18%, P < 0.001) were more frequent in patients with new-onset AF. Multivariable logistic regression analysis showed that Killip classification ≥ 3 (odds ratio, 6.97; 95% confidence interval [CI], 2.77-17.52; P < 0.001), and ischemic occlusion of the atrial branch of the right coronary artery (odds ratio, 4.35; 95% confidence interval, 1.91-9.93; P < 0.001) were independent predictors of new-onset AF. Altogether, proximal occlusion in the right coronary artery involving the atrial branch is a strong predictor of new-onset AF after AMI.