Recently Diagnosed Atrial Fibrillation in Patients with Acute Coronary Syndrome: Results of the FORCE-ACS Registry

Atrial fibrillation (AF) is a common condition in patients with acute coronary syndrome (ACS). About 10% of patients undergoing percutaneous coronary intervention (PCI) have AF, while 25%-35% of patients with AF have coronary artery disease. The joint management of both conditions poses a significant challenge, as the combination of oral anticoagulation (OAC) and dual antiplatelet therapy (DAPT), known as triple therapy, is associated with a high risk of bleeding complications.

There is limited information regarding the prognosis and optimal antithrombotic treatment in patients with newly diagnosed AF during ACS. Observational studies have shown that these patients with AF and ACS often receive inadequate treatment, as OAC is not always prescribed. Therefore, it is crucial to determine whether newly diagnosed AF entails a higher risk of thromboembolic events.

The aim of this multicenter, prospective study was to assess the incidence of de novo AF in patients with ACS, compare clinical outcomes between those without AF, subjects with de novo AF, and those with known AF, and analyze antithrombotic treatment in relation to major adverse cardiovascular events (MACE), with particular attention to stroke.

The primary endpoint (PEP) was the rate for MACE, defined as all-cause mortality, acute myocardial infarction (AMI), and ischemic stroke. The secondary endpoint (SEP) included ischemic stroke and bleeding complications.

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The study included 4433 patients with ACS, of whom 81.2% had no AF, 9.9% had newly diagnosed AF, and 9% had known AF. Patients with newly diagnosed AF and known AF were older and had more comorbidities compared with those without AF (mean age 71, 74, and 65 years, respectively; p < 0.001). The rate of OAC treatment at discharge was 53.4% in patients with de novo AF and 89.2% in patients with known AF.

De novo AF was independently associated with an increased rate of MACE, whereas known AF did not evidence this association (hazard ratio [HR] 1.52; 95% confidence interval [CI] 1.19-1.90 vs. HR 0.93; 95% CI 0.70-1.23). In patients diagnosed with ACS and newly onset AF, AF episodes lasting longer than 24 hours were associated with a higher risk of MACE compared with episodes lasting less than 24 hours (HR 1.99; 95% CI: 1.36-2.93).

Conclusion

In patients with ACS, newly diagnosed AF was associated with worse outcomes in terms of MACE and ischemic stroke. In those with newly diagnosed AF, AF episodes lasting longer than 24 hours were linked to worse outcomes compared with shorter episodes. Additionally, only half of the patients with de novo AF were discharged with OAC, in contrast to more than 90% of patients with known AF.

Original Title: Outcomes of newly diagnosed atrial fibrillation in patients with acute coronary syndromes.

Reference: Willem Lambertus (Wilbert) Bor, MD et al EuroIntervention 2024;20:996-1007.