title: Impact of atrial fibrillation type during acute coronary syndromes: Clinical features and prognosis.
abstract: BACKGROUND
  Atrial fibrillation (AF) is widely recognized as an adverse prognostic factor during acute myocardial infarction, although the impact of AF type - new-onset (nAF) or pre-existing (pAF) - is still controversial.
  
  
  OBJECTIVE
  To identify the clinical differences and prognosis of nAF and pAF during acute coronary syndromes (ACS).
  
  
  METHODS
  We performed a retrospective observational cohort study including 1373 consecutive patients (mean age 64 years, 77.3% male) admitted to a single center over a three-year period, with a six-month follow-up.
  
  
  RESULTS
  AF rhythm was identified in 14.5% patients, of whom 71.4% presented nAF and 28.6% pAF. When AF types were compared, patients with nAF more frequently presented with ST-elevation ACS (p=0.003). Patients with pAF, in turn, were older (p=0.032), had greater left atrial diameter (p=0.001) and were less likely to have significant coronary lesions (p=0.034). Regarding therapeutic strategy, nAF patients were more often treated by rhythm control during hospital stay (p<0.001) and were less often anticoagulated at discharge (p=0.001). Compared with the population without AF, nAF was a predictor of death during hospital stay in univariate (p<0.001) and multivariate analysis (OR 2.67, p=0.047), but pAF was not. During follow-up, pAF was associated with higher mortality (p=0.014), while nAF patients presented only a trend towards worse prognosis.
  
  
  CONCLUSIONS
  AF during the acute phase of ACS appears to have a negative prognostic impact only in patients with nAF and not in those with pAF.
authors.affiliation: Serviço de Cardiologia, Hospital de Braga, Braga, Portugal. Electronic address: carlos.galvaobraga@gmail.com.
authors.forename: Carlos Galvão
authors.initials: CG
authors.lastname: Braga
authors.affiliation: Serviço de Cardiologia, Hospital de Braga, Braga, Portugal.
authors.forename: Vítor
authors.initials: V
authors.lastname: Ramos
authors.affiliation: Serviço de Cardiologia, Hospital de Braga, Braga, Portugal.
authors.forename: Juliana
authors.initials: J
authors.lastname: Martins
authors.affiliation: Serviço de Cardiologia, Hospital de Braga, Braga, Portugal.
authors.forename: Carina
authors.initials: C
authors.lastname: Arantes
authors.affiliation: Serviço de Cardiologia, Hospital de Braga, Braga, Portugal.
authors.forename: Glória
authors.initials: G
authors.lastname: Abreu
authors.affiliation: Serviço de Cardiologia, Hospital de Braga, Braga, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Vieira
authors.affiliation: Serviço de Cardiologia, Hospital de Braga, Braga, Portugal.
authors.forename: Alberto
authors.initials: A
authors.lastname: Salgado
authors.affiliation: Serviço de Cardiologia, Hospital de Braga, Braga, Portugal.
authors.forename: António
authors.initials: A
authors.lastname: Gaspar
authors.affiliation: Serviço de Cardiologia, Hospital de Braga, Braga, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Azevedo
authors.affiliation: Serviço de Cardiologia, Hospital de Braga, Braga, Portugal.
authors.forename: Miguel
authors.initials: M
authors.lastname: Álvares Pereira
authors.affiliation: Serviço de Cardiologia, Hospital de Braga, Braga, Portugal.
authors.forename: Sónia
authors.initials: S
authors.lastname: Magalhães
authors.affiliation: Serviço de Cardiologia, Hospital de Braga, Braga, Portugal.
authors.forename: Jorge
authors.initials: J
authors.lastname: Marques
mesh_terms: D054058:Acute Coronary Syndrome / Q000150:complications*; D000368:Aged; D001281:Atrial Fibrillation / Q000145:classification* / Q000150:complications*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies
keywords: Acute coronary syndrome; Atrial fibrillation; Fibrilhação auricular; Prognosis; Prognóstico; Síndrome coronária aguda