Prognostic impact of newly diagnosed atrial fibrillation and episode characteristics in patients with acute coronary syndrome

Abstract

Listen

Translate article

Abstract Background/Introduction Newly diagnosed atrial fibrillation (AF) frequently occurs during acute coronary syndrome (ACS). In contrast to known AF, little is known about the prognostic and therapeutic implications of new AF. Purpose To evaluate the prognostic impact of newly diagnosed and known AF in patients with ACS. Furthermore, we evaluated the association of episode characteristics of new AF with clinical outcomes: early vs late occurrence, short vs long duration, post-CABG occurrence, and OAC treatment. Methods This analysis was performed within the prospective, multicentre, FORCE-ACS registry which studies ACS patients in the Netherlands. All ECGs during index ACS admission were retrospectively examined for the occurrence of AF. Patients were classified as no, new, or known AF. New AF episodes were described regarding early or late occurrence, duration of the episode, and post-CABG occurrence, and OAC prescription at discharge was evaluated. The primary outcome was MACE, a composite of death, myocardial infarction and stroke. Secondary outcomes include the separate MACE components and bleeding. Crude and adjusted outcomes were evaluated by univariable and multivariable Cox regression. Results 3902 patients were included of which 299 (10.2%) had new and 367 (9.4%) had known AF. Major adverse cardiac events happened significantly more in both new and known AF patients than in patients without AF (22.2%, 17.4%, and 9.2%, p<0.001). Ischemic stroke occurred significantly more in new AF but not in known AF patients, compared to patients without AF (3.5% vs 0.9% vs 1.1%). After one year follow-up, a total of 234 patients (6.3%) deceased, of whom 138 in the group without AF (4.6%), and significantly more in the groups with new AF (n=59, 15.9%), and known AF (n=37, 10.8%). The timing of onset of the AF episode showed no significant association with clinical outcomes. Longer duration of the episode, however, was associated with increased MACE (HR 2.0, 95% CI 1.2–3.1) and all-cause mortality (HR 2.0, 95% CI 1.2–3.4). Episodes of new AF that occurred post-CABG were associated with less MACE (HR 0.31, 95% CI 0.14–0.67) and all-cause mortality (HR 0.20, 95% CI 0.07–0.55). No significant association between OAC treatment and MACE nor any of its separate components was found. Conclusion Newly diagnosed atrial fibrillation in acute coronary syndromes is associated with worse clinical outcomes than known or no atrial fibrillation. Longer episodes were associated with worse outcomes than short episodes. Post-operative new AF was associated with better outcomes than non-post-operative new AF. Funding Acknowledgement Type of funding sources: None.