Prognostic value of admission electrocardiographic findings in non-ST-segment elevation myocardial infarction

Admission electrocardiographic (ECG) findings of non-ST-segment elevation myocardial infarction (NSTEMI) include transient ST-segment elevation (TSTE), ST-segment depression (STD), T-wave inversion (TWI), and no ischemic changes (NIC).

This study aimed to assess the prognostic value of qualitative ECG findings at presentation and to clarify the influence of invasive treatment on the prognostic value of admission ECG findings.

We analyzed the Acute Coronary Syndrome Quality Improvement in Kerala (ACS QUIK) study post hoc. NSTEMI patients were included and classified into four groups per ECG findings. Study endpoints were in-hospital and 30-day mortality rates and major adverse events (MAE). We performed multivariate logistic regression, adjusting for covariates in the Global Registry of Acute Coronary Events risk model, with subset analyses of patients treated with or without invasive management.

STD patients had significantly higher in-hospital and 30-day mortality rates/MAE than TWI patients, which had lower in-hospital mortality rate/MAE than the NIC group. TSTE patients had intermediate outcomes. In multivariate logistic regression using the TWI group as the reference, STD and NIC remained independently associated with worse outcomes. Subset analysis showed prognostic value of admission ECG in non-invasively managed but not in invasively managed patients.

STD was associated with adverse outcomes, TWI with benign prognoses. NIC should not be taken to indicate low risk. Qualitative analysis of admission ECG is suitable for rapid risk stratification of NSTMI patients at presentation. However, it may not be predictive of short-term outcomes of NSTEMI patients after invasive management.