Which of the following is an essential component of the primary assessment for suspected ACS?

Establishing cardiac monitoring is crucial during the primary assessment of a patient suspected of acute coronary syndrome (ACS) because it allows for the continuous observation of the heart's electrical activity. This monitoring can help identify life-threatening arrhythmias or other cardiac complications that may develop as the situation evolves. Early detection of these issues is vital for timely interventions, including the administration of medications or preparations for advanced treatments.

In contrast, gathering a complete medical history, while important in the overall patient care process, typically occurs after the primary assessment and is not an immediate priority during the initial assessment of ACS. Waiting for patient stabilization is not advisable as immediate monitoring and intervention can improve outcomes. Conducting a physical examination without monitoring can overlook critical changes in the patient's condition, potentially delaying necessary interventions that are informed by the realtime data provided by cardiac monitoring.