A nurse-led pre-hospital triage service for identifying patients with occlusive myocardial infarction: a service evaluation

Background/Aims Acute coronary syndromes include unstable angina and myocardial infarction, of which occlusive myocardial infarction is a high-risk subset that is often missed because of a lack of ST elevation. Pre-hospital electrocardiograms may be able to identify myocardial infarction early and reduce mortality. However, it is unclear whether pre-hospital electrocardiograms can accurately detect occlusive myocardial infarction and how this affects outcomes. This study will analyse the outcomes of patients with occlusive myocardial infarction who had a pre-hospital electrocardiogram. Method Electrocardiograms transmitted to the coronary care unit triage service were identified, along with data regarding patient demographics, referrals and mortality. Data were analysed for correlations between demographic and clinical factors and type of myocardial infarction. Results A total of 838 electrocardiograms were identified; 69 (8.2%) showed myocardial infarction and eight (1.0%) showed occlusive myocardial infarction, of which 50% had ST elevation. Patients with occlusive myocardial infarction were more likely to be triaged to the coronary care unit than patients with non-occlusive myocardial infarction (P=0.04). However, 38 (55.1%) of the patients with myocardial infarction and four (50.0%) of the patients with occlusive myocardial infarction were not directed to a coronary care unit or the catheterisation laboratory. Patients with occlusive myocardial infarction had higher index episode mortality rates (P=0.03) and 30-day mortality rates (P<0.01). Conclusions Despite pre-hospital electrocardiogram transmission and adherence to the guidelines, triage of myocardial infarction and occlusive myocardial infarction is imperfect. Refinement of risk scores and adaptation of new technology is required to help identify patients with occlusive myocardial infarction so they can be prioritised for immediate reperfusion therapy.