Comparative clinical implications of admission electrocardiographic findings for patients with non-ST-segment elevation myocardial infarction

Long-term outcomes in patients with acute myocardial infarction and no ischemic changes on electrocardiogram

BACKGROUND

Acute myocardial infarction (MI) is commonly associated with ischemic abnormalities on electrocardiography (ECG). However, a significant proportion of patients present with no ischemic changes (NIC), and their baseline characteristics and management differ considerably from those with other ECG patterns. In the era of rapid troponin assays, the exact prognostic effects of normal ECGs remain unclear.

OBJECTIVES

This study aimed to compare the outcomes of patients with MI without ischemic changes and those with other ECG patterns.

METHODS

Between 2012 and 2018, 155,073 patients with MI were enrolled in the prospective nationwide Polish Registry of Acute Coronary Syndromes (PL-ACS). The patients were assigned to one of the following groups: NIC, ST-segment elevation (STE), ST-segment depression (STD), T-wave inversion (TWI), and other ST-T abnormalities (STT).

RESULTS

The NIC group accounted for 9.56% of all patients. The in-hospital risk of death was lower in the TWI group than in the NIC group. In the STE, STD, and STT groups, the short-term results were substantially worse. During the 12-month observation period, TWI had the best prognosis. The worst long-term prognoses were associated with STT and STD. The outcomes of the STE and NIC groups were similar (12-month death rate 9.0% vs. 8.7%, respectively; P=0.534), despite the fact STE was an independent predictor of 12-month prognosis.

CONCLUSIONS

The prognosis of patients with MI and NIC is not as favorable as previously thought. Their long-term outcomes were equal to those of the TWI and STE MI groups.

Medication Administration Delays in Non-ST Elevation Myocardial Infarction: Analysis of 1002 Patients Admitted to an Academic Medical Center

Our goal was to assess adherence to American College of Cardiology/American Heart Association guideline-based medical therapy in patients admitted with type I non-ST elevation myocardial infarction (NSTEMI) and to determine factors associated with medication administration delay. We performed a retrospective analysis using data from the Acute Coronary Treatment and Intervention Outcomes Network (ACTION) Registry. Baseline patient demographics, 12-lead electrocardiogram (ECG) findings, laboratory values, medications administered and the time they were administered, and in-hospital clinical outcomes were collected. Global Registry of Acute Coronary Events risk scores were calculated for all patients. We included 1002 patients admitted from the emergency department with a type I NSTEMI. A total of 802 (80%) patients received appropriate initial therapy consisting of therapeutic anticoagulation with heparin and dual antiplatelet therapy. Of the 200 (20%) patients who did not receive therapy, documentation in the chart regarding possible contraindications for administration of the medications was missing in up to half. Female sex, older age, a normal initial ECG, and prolonged time spent in the emergency department were predictors of significant delay in receiving guideline-based medications, while an elevated initial troponin was a predictor of faster medication administration. Global Registry of Acute Coronary Events risk scores had no association with the timing of medication administration. In conclusion, 20% of NSTEMI patients did not receive American College of Cardiology/American Heart Association guideline-based medical therapy. Delay in medication administration was significant for women, older individuals, and patients who did not have ischemic findings on the initial ECG.