Aim: To compare accuracy and certainty of diagnosis of cardiac ischaemia using the Panoramic ECG display tool plus conventional 12 lead electrocardiogram (ECG) versus 12 lead ECG alone by UK critical care nurses who were members of the British Association of Critical Care Nurses (BACCN). Background: Critically ill patients are prone to myocardial ischaemia. Symptoms may be masked by sedation or analgesia, and ECG changes may be the only sign. Critical care nurses have an essential role in detecting ECG changes promptly. Despite this, critical care nurses may lack expertise in interpreting ECGs and myocardial ischaemia often goes undetected by critical care staff. Method: British Association of Critical Care Nurses (BACCN) members were invited to complete an online survey to evaluate analysis of two sets of eight ECGs displayed alone and with the new display device.Results: Data from 82 participants showed diagnostic accuracy improved from 67.1% reading ECG traces alone, to 96.0% reading ECG plus Panoramic ECG display tool (P <0.01, significance level α = 0.05). Participants’ diagnostic certainty score rose from 41.7% reading ECG alone, to 66.8% reading ECG plus Panoramic ECG display tool (P <0.01, α = 0.05).Conclusion: The Panoramic ECG display tool improves both accuracy and certainty of detecting ST segment changes among critical care nurses, when compared to conventional 12 lead ECG alone. This benefit was greatest with early ischaemic changes. Critical care nurses who are least confident in reading conventional ECGs benefit the most from the new display.Relevance to clinical practice: Critical care nurses have an essential role in the monitoring of critically ill patients. However, nurses do not always have the expertise to detect subtle ischaemic ECG changes promptly. Introduction of the Panoramic ECG display tool into clinical practice could lead to patients receiving treatment for myocardial ischaemia sooner with the potential for reduction in morbidity and mortality.