Final answer:
Based on the patient's symptoms and initial assessment findings, the ACLS algorithm that should be followed is 'Adult Tachycardia With a Pulse'.
Step-by-step explanation:
Based on the patient's initial assessment, the ACLS algorithm that should be followed is Adult Tachycardia With a Pulse. The patient's symptoms of light-headedness, nausea, chest discomfort, and weak, thready, fast radial pulse indicate a tachycardic condition. The algorithm will guide the healthcare provider in assessing and managing the patient's condition, including interventions such as administering oxygen, obtaining blood pressure, and providing appropriate treatment.