While the prognosis of patients presenting with de-novo atrial fibrillation during the acute phase of myocardial infarction has been controversially discussed, it seems intuitive that affected individuals have an increased risk for both thromboembolic events and mortality. However, profound data on long-term outcome of this highly vulnerable patient population are not available in current literature. Therefore, we aimed to investigate the impact of de-novo atrial fibrillation and associated anti-thrombotic treatment strategies on the patient outcome from a long-term perspective.
Patients presenting with acute myocardial infarction, treated at the Medical University of Vienna, were enrolled within a clinical registry and screened for the development of de-novo atrial fibrillation. After discharge participants were followed prospectively over a median time of 8.6 years. Primary study endpoint was defined as cardiovascular mortality.Out of 1372 enrolled individuals 149 (10.9%) developed de-novo atrial fibrillation during the acute phase of acute myocardial infarction. After a median follow-up time of 8.6 years, a total of 418 (30.5%) died due to cardiovascular causes, including 93 (62.4%) in the de-novo atrial fibrillation subgroup. We found that de-novo atrial fibrillation was significantly associated with long-term cardiovascular mortality with an adjusted HR of 1.45 (95%CI: 1.19-2.57; p < 0.001). While patients with de-novo atrial fibrillation were less likely to receive a triple anti-thrombotic therapy as compared to patients with pre-existing atrial fibrillation at time of discharge, this therapeutic approach showed a strong and inverse association with mortality in de-novo atrial fibrillation, with an adj. HR of 0.86 (95%CI: 0.45-0.92; p = 0.012).
De-novo atrial fibrillation was independently associated with a poor prognosis with a 67% increased risk of long-term cardiovascular mortality. Intensified anti-thrombotic treatment in this high-risk patient population might be considered.

© Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2020. For permissions, please email: journals.permissions@oup.com.