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Diagnosing, fast and slow
  1. JJ Coughlan1,
  2. Cormac Francis Mullins2,
  3. Thomas J Kiernan3
  1. 1 Cardiology, Saint James’s Hospital, Dublin, Ireland
  2. 2 Trinity College, Dublin, Ireland
  3. 3 Cardiology, University Hospital Limerick, Dooradoyle, Ireland
  1. Correspondence to JJ Coughlan, Department of Cardiology, St James’ Hospital, KIlmainham, Dublin 8, Ireland; jjcoughl{at}


Diagnostic error is increasingly recognised as a source of significant morbidity and mortality in medicine. In this article, we will attempt to address several questions relating to clinical decision making; How do we decide on a diagnosis? Why do we so often get it wrong? Can we improve our critical faculties?

We begin by describing a clinical vignette in which a medical error occurred and resulted in an adverse outcome for a patient. This case leads us to the concepts of heuristic thinking and cognitive bias. We then discuss how this is relevant to our current clinical paradigm, examples of heuristic thinking and potential mechanisms to mitigate bias.

The aim of this article is to increase awareness of the role that cognitive bias and heuristic thinking play in medical decision making. We hope to motivate clinicians to reflect on their own patterns of thinking with an overall aim of improving patient care.

  • Cardiology
  • adult cardiology
  • coronary intervention
  • myocardial infarction
  • valvular heart disease

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  • Contributors JJC was primarily responsible for the drafting of the manuscript and the original concept. JJC is the principal author of this manuscript. CFM and TJK were involved in the conception of this project and provided editorial feedback

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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