Background:

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia worldwide and has a close correlation with acute coronary syndromes. The aim of our study is to describe the incidence, predisposing factors and outcome of patients with de novo AF after an acute coronary syndrome in a population representative of our environment.

Methods:

We conducted a sub-analysis of the BUENOS AIRES I registry, which included 1110 patients with non- ST-segment elevation acute coronary syndrome (NSTE-ACS) followed-up at 6 months.

Results:

The incidence of de novo AF was 7.7%. The independent predictors of de novo AF were age (OR, 1.04; 95% CI, 1.021.08; p = 0.001), initial presentation as MI (OR, 2.35; 95% CI, 1.20-4.57; p = 0.012) and requirement of myocardial revascularization surgery (OR 6.86; 95% CI 3.95-11.89; p < 0.001). Patients who developed AF had greater all-cause mortality, cardiovascular mortality and bleeding events ≥BARC type 2. The development of de novo AF after NSTE-ACS was identified as an independent predictor of cardiovascular mortality (OR, 3.67; 95% CI 1.25-10.76; p = 0.018) and of bleeding events ≥ BARC type 2 (OR, 3.024; 95% CI, 1.49-6.11; p = 0.002).

Conclusions:

This prespecified sub-analysis of the BUENOS AIRES I registry demonstrated a significant incidence of de novo AF in the setting of a NSTE-ACS, associated with elderly patients, greater acute myocardial structural damage and need for myocardial revascularization surgery, with worse outcome in terms of adverse clinical events at mid-term follow-up.