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

Sharon O'Donnell, Gabrielle McKee, Mary Mooney, Frances O'Brien, Debra K. Moser

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


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.

Original languageEnglish
Pages (from-to)507-515
Number of pages9
JournalJournal of Emergency Medicine
Issue number4
StatePublished - Apr 2014

Bibliographical note

Funding Information:
The authors wish to thank the patients who gave of their time and agreed to be interviewed for this study. This study is funded by the Health Research Board , Dublin, whose support is greatly appreciated.


  • ACS presentations
  • Acute Coronary Syndrome symptoms
  • fast-onset ACS
  • patient decision delay
  • slow-onset ACS

ASJC Scopus subject areas

  • Emergency Medicine


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