Slow-onset and fast-onset symptom presentations in acute coronary syndrome (ACS): new perspectives on prehospital delay in patients with ACS

J Emerg Med. 2014 Apr;46(4):507-15. doi: 10.1016/j.jemermed.2013.08.038. Epub 2013 Oct 11.


Background: Patient decision delay is the main reason why many patients fail to receive timely medical intervention for symptoms of acute coronary syndrome (ACS).

Study objectives: 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.

Conclusion: 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.

Keywords: ACS presentations; Acute Coronary Syndrome symptoms; fast-onset ACS; patient decision delay; slow-onset ACS.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Coronary Syndrome / complications*
  • Acute Coronary Syndrome / therapy*
  • Aged
  • Ambulances / statistics & numerical data
  • Chest Pain / etiology*
  • Decision Making
  • Female
  • General Practitioners / statistics & numerical data
  • Humans
  • Male
  • Middle Aged
  • Patient Acceptance of Health Care*
  • Patient Acuity
  • Time Factors
  • Time-to-Treatment