0299: De Novo Atrial Fibrillation in the Acute Coronary Syndrome

De novo atrial fibrillation (AF) is common in the acute coronary syndrome (ACS), but most patients (P) are discharged in sinus rhythm (SR). The recurrence of arrhythmia in follow-up (FU) remains unknown and its undervaluation may have prognostic impact. To characterize a population with ACS and de novo AF and determine its prognostic impact. To evaluate the recurrence of AF and the incidence of ischemic stroke/systemic embolism in FU. We analyzed 2383 P consecutivelly admitted with ACS and with a minimum of 180 days FU. De novo AF has been defined as AF first detected on admission or during hospitalization. It has been observed de novo AF in 199 P (8.4%), the majority being male (70.4%). These patients were significantly older (p<0.001) and had higher HTA prevalence (p<0.001. The echocardiographic evaluation showed a higher prevalence of mitral insufficiency (p<0.001) and left ventricular ejection fraction <40% (p<0.001). These P developed more frequently heart failure (p<0.001) and stroke (p=0.001) during hospitalization. The in-hospital mortality (9.5% vs 3.3%, p<0.001) and at 6 months (15.6% vs 6.6%, p<0.001) were also higher, however, the presence of de novo AF was not an independent predictor of these events. Most P were discharged in SR (n=134) and without anticoagulant therapy (n=117). 95 patients with de novo AF were followed for a median period of 690 days and it was observed the occurrence of ischemic stroke/systemic embolism in 9 P (9.5%), but only one was under oral anticoagulation. AF occurred in 37.5% of P that were in SR on discharge. The presence of de novo AF was associated with increased risk of adverse events, although it may constitute only a marker of severity. We observed recurrence of AF in a considerable sample, which denotes the need for appropriate evaluation of thromboembolic risk of these P.