What immediate action should be taken for a patient with STEMI who presents with chest pain and has not undergone primary PCI within 90 minutes?

In the case of a STEMI (ST-Elevation Myocardial Infarction), timely intervention is crucial for reducing morbidity and mortality. Primary PCI (Percutaneous Coronary Intervention) is the preferred treatment method for STEMI, especially if it can be performed promptly.

When a patient presents with STEMI and has not undergone primary PCI within 90 minutes, preparing for the procedure immediately is the most appropriate step. This action directly addresses the underlying cause of the myocardial infarction by restoring blood flow to the affected myocardium through mechanical intervention, which can significantly improve clinical outcomes.

While fibrinolytics can be considered if PCI is not available and the patient is a candidate, they are not regarded as a first-line treatment if PCI can be performed in a timely manner. Monitoring for additional symptoms does not provide immediate therapeutic benefit, nor does administering nitroglycerin, which primarily serves to alleviate chest pain but does not address the urgent need to restore coronary blood flow.