Long-term prognosis of de novo atrial fibrillation during acute myocardial infarction: the impact of anti-thrombotic treatment strategies

Aims: While the prognosis of patients presenting with de novo atrial fibrillation (AF) during the acute phase of myocardial infarction has been controversially discussed, it seems intuitive that affected individuals have an increased risk for both thrombo-embolic 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 AF and associated anti-thrombotic treatment strategies on the patient outcome from a long-term perspective.

Methods and results: 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 AF. 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 AF 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 AF subgroup. We found that de novo AF 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 AF were less likely to receive a triple anti-thrombotic therapy as compared to patients with pre-existing AF at time of discharge, this therapeutic approach showed a strong and inverse association with mortality in de novo AF, with an adj. HR of 0.86 (95% CI 0.45-0.92; P = 0.012).

Conclusion: De novo AF 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.