In evaluating a 58-year-old man with chest discomfort, particularly with the given vital signs (blood pressure of 92/50 mm Hg, heart rate of 92/min, respiratory rate of 14 breaths/min, and pulse oximetry of 97%), the most important assessment step now is to obtain a 12-lead electrocardiogram (ECG).

Reasoning:

1. Chest Discomfort: Chest discomfort can be a symptom of acute coronary syndrome (ACS), which includes conditions like myocardial infarction (heart attack) and unstable angina.
2. Vital Signs: The patient’s blood pressure is on the lower side (hypotensive), which could indicate hemodynamic instability potentially due to cardiac issues.
3. ECG Importance: An ECG is crucial for identifying any signs of ischemia, infarction, or arrhythmias. It provides immediate and essential information that can guide further management.
4. Prompt Diagnosis: Early identification of cardiac ischemia or other abnormalities on the ECG can lead to prompt treatment, which is critical in acute coronary syndromes to improve outcomes.