title: Slow-onset and fast-onset symptom presentations in acute coronary syndrome (ACS): new perspectives on prehospital delay in patients with ACS.
abstract: BACKGROUND
  Patient decision delay is the main reason why many patients fail to receive timely medical intervention for symptoms of acute coronary syndrome (ACS).
  
  
  OBJECTIVE
  This study examines the validity of slow-onset and fast-onset ACS presentations and their influence on ACS prehospital delay times. A fast-onset ACS presentation is characterized by sudden, continuous, and severe chest pain, and slow-onset ACS pertains to all other ACS presentations.
  
  
  METHODS
  Baseline data pertaining to medical profiles, prehospital delay times, and ACS symptoms were recorded for all ACS patients who participated in a large multisite randomized control trial (RCT) in Dublin, Ireland. Patients were interviewed 2-4 days after their ACS event, and data were gathered using the ACS Response to Symptom Index.
  
  
  RESULTS
  Only baseline data from the RCT, N = 893 patients, were analyzed. A total of 65% (n = 577) of patients experienced slow-onset ACS presentation, whereas 35% (n = 316) experienced fast-onset ACS. Patients who experienced slow-onset ACS were significantly more likely to have longer prehospital delays than patients with fast-onset ACS (3.5 h vs. 2.0 h, respectively, t = -5.63, df 890, p < 0.001). A multivariate analysis of delay revealed that, in the presence of other known delay factors, the only independent predictors of delay were slow-onset and fast-onset ACS (β = -.096, p < 0.002) and other factors associated with patient behavior.
  
  
  CONCLUSIONS
  Slow-onset ACS and fast-onset ACS presentations are associated with distinct behavioral patterns that significantly influence prehospital time frames. As such, slow-onset ACS and fast-onset ACS are legitimate ACS presentation phenomena that should be seriously considered when examining the factors associated with prehospital delay.
authors.affiliation: School of Nursing and Midwifery, University of Dublin, Trinity College, Dublin, Ireland.
authors.forename: Sharon
authors.initials: S
authors.lastname: O'Donnell
authors.affiliation: School of Nursing and Midwifery, University of Dublin, Trinity College, Dublin, Ireland.
authors.forename: Gabrielle
authors.initials: G
authors.lastname: McKee
authors.affiliation: School of Nursing and Midwifery, University of Dublin, Trinity College, Dublin, Ireland.
authors.forename: Mary
authors.initials: M
authors.lastname: Mooney
authors.affiliation: School of Nursing and Midwifery, University of Dublin, Trinity College, Dublin, Ireland.
authors.forename: Frances
authors.initials: F
authors.lastname: O'Brien
authors.affiliation: University of Kentucky College of Nursing, Lexington, Kentucky.
authors.forename: Debra K
authors.initials: DK
authors.lastname: Moser
mesh_terms: D054058:Acute Coronary Syndrome / Q000150:complications* / Q000628:therapy*; D000368:Aged; D000552:Ambulances / Q000706:statistics & numerical data; D002637:Chest Pain / Q000209:etiology*; D003657:Decision Making; D005260:Female; D058005:General Practitioners / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D010342:Patient Acceptance of Health Care; D062072:Patient Acuity; D013997:Time Factors; D061665:Time-to-Treatment
keywords: ACS presentations; Acute Coronary Syndrome symptoms; fast-onset ACS; patient decision delay; slow-onset ACS