What should be done if the initial ECG is not diagnostic but the patient remains symptomatic and there is a high clinical suspicion for ACS?
Serial ECGs (eg, 15- to 30-minute intervals during the first hour) should be performed to detect ischemic changes. Additionally, serial cardiac troponin I or T levels should be obtained at presentation and 3 to 6 hours after symptom onset. Additional troponin levels should be obtained beyond 6 hours after symptom onset in patients with normal troponin levels on serial examination when changes on ECG and/or clinical presentation confer an intermediate or high index of suspicion for ACS.