A Clinical Risk Case Study- A Missed Diagnosis of Myocardial Infarction in A&E

A Clinical Risk Case Study- A Missed Diagnosis of Myocardial Infarction in A&E

Setting the Scene

The Patient, who had a previous history of myocardial infarction (MI) and stroke, attended A&E with central chest pain. A history was taken and an ECG performed, which was abnormal. The ECG abnormality was not recognised and the Patient was discharged with a diagnosis of non-cardiac chest pain. The Patient’s MI was subsequently diagnosed upon readmission by ambulance a few days later. Sadly, the Patient died as a result of complications of the MI.

The main learning points from this review stem from the following events:

  1. Not taking a full history from the Patient regarding the nature of the chest pain and its duration.

  2. Not noting the Patient’s cardiac risk factors by using a validated risk assessment tool.

  3. Not recognising the abnormality on the Patient’s ECG.

  4. Not admitting the Patient in light of the abnormal ECG findings in order to repeat key tests which would have resulted in the diagnosis of MI.

Recommendations to Prevent Incident Recurrence and Improve Patient Safety

TMLEP’s recommendations to reduce recurrence and enhance patient safety are as follows:

  1. When a patient presents with chest pain to A&E, it is essential that a detailed history of the pain is taken. Such a history should include: the duration of the pain, the similarity to any previous episodes of pain, any recent increase in episodes of pain, any exacerbating/relieving factors which affect the pain and any associated symptoms. Chest pain can be indicative of many different diagnoses including MI, pulmonary embolism/deep vein thrombosis, traumatic injury, pneumonia or chest infection, and thus the clinician should be looking to verify their diagnosis by taking a full and detailed history.

  2. If chest pain is present, it is imperative that the patient’s cardiac risk factors (such as previous MI, hypertension, diabetes, gender, and age) are noted and that the clinician shows that they have taken these into consideration prior to making a diagnosis and determining whether further cardiac investigation is required. There should be clear evidence of a cardiac risk assessment – this can be easily validated by using a tool such as the HEART score for major cardiac events (1). TMLEP also wishes to highlight the importance of the NICE Guideline [CG95] regarding the management of chest pain of recent onset in this scenario (2).

  3. ECGs taken in A&E due to recent onset chest pain should be carefully considered and clinicians should receive up to date and regular training on identifying abnormalities on an ECG. This is because ECG changes such as pathological Q waves in combination with a raised troponin are sufficient to diagnose an MI in line with NICE Guideline [CG95] (2).

  4. Where ECG abnormalities are identified in the context of patients with chest pain, such patients should not be discharged from A&E and should be admitted for further cardiac investigations including repeat ECG and troponin measurements in order to confirm the diagnosis of MI and obtain cardiology review. TMLEP wishes to highlight the importance of robust Acute Coronary Syndrome protocols (such as NICE Quality standard [QS68]).

To Summarise

The Patient was discharged and MI not diagnosed upon attendance to A&E. A full history of the chest pain was not obtained, cardiac risk factors not considered and abnormalities on the ECG were not identified. The Patient should have been admitted for further investigations and cardiology review.

It is imperative that where patients present with recent onset chest pain that a full detailed history is taken in A&E in order to consider the myriad of diagnoses which could be the cause of the pain. Patients’ cardiac risk factors should be assessed in order to identify patients at high risk of cardiac conditions, which add more weight to a differential diagnosis of MI.

Clinicians in A&E should be up to date and regularly trained on the identification of ECG abnormalities, which is a key factor in diagnosing MI. Where ECG abnormalities are identified, patients should be admitted for further cardiac investigations and cardiology review in order to confirm the diagnosis of MI. A missed or delayed diagnosis of MI can lead to a devastating outcome for patients and pose a risk to patient safety which can be mitigated by following what is now well-established clinical guidance.


  • 1. https://www.mdcalc.com/heart-score-major-cardiac-events
  • 2. National Institute for Health and Care Excellence. 2010. Chest pain of recent onset: assessment and diagnosis. [CG95].
  • 3. National Institute for Health and Care Excellence. 2014. Acute coronary syndromes in adults. [QS68].
  • 4. Co-written by The TMLEP Clinical Risk and Patient Safety Publishing Group, Rebecca Beaumont LLB and Dr Syed Masud MBBS, FRCEM, DMCC, DiplMC(RCSed), FIMC(RCSed), DMCC, MSc, PgC RAMC (Rtd). (2019). A Clinical Risk Case Study- A Missed Diagnosis of Myocardial Infarction in A&E. TMLEP Clinical Risk Case Studies. 2 (8), 1.

Important Note

This article is intended to raise awareness to clinical risk issues in an effort to reduce incidence recurrence and improve patient safety. This is not intended to be relied upon as advice. Facts have been altered to ensure this case is non-identifiable, albeit clinical learning points remain applicable. To request an independent clinical review, please contact admin@tmlep.com or call +44 (0) 203 355 9796.