Management of Chest Pain or Shortness of Breath with Inconclusive ECG

Immediate Actions Upon Presentation

The American College of Cardiology recommends performing a 12-lead ECG within 10 minutes of arrival to any medical facility, regardless of setting 1, 2
The American College of Cardiology suggests measuring cardiac troponin (cTn) as soon as possible after ED presentation, with high-sensitivity troponin preferred for rapid detection 1, 2

If ST-segment elevation is present, the American College of Cardiology recommends managing as STEMI with immediate reperfusion therapy (thrombolytics or primary PCI depending on transfer time and facility capabilities) 1, 2
If ST-segment depression or new T-wave inversions are present, the American Heart Association recommends managing as NSTE-ACS with aspirin, beta-blockers, nitrates, and low-molecular-weight heparin 4
A normal or nondiagnostic ECG occurs in 30-40% of patients with acute MI and does NOT exclude ACS, according to the European Heart Journal 5, 4

The American College of Cardiology recommends repeating troponin at 6-12 hours from symptom onset (not from presentation time) to detect myocardial injury 2, 3
Serial ECGs should be performed every 15-30 minutes during the first hour if symptoms persist or recur, as suggested by the American Heart Association 4, 3

High-risk features requiring immediate angiography include persistent or recurrent ischemic chest pain despite medical therapy, dynamic ECG changes, positive second troponin measurement or rising pattern, hemodynamic instability, and life-threatening arrhythmias, according to the American College of Cardiology 2, 3, 1
Low-risk criteria allowing discharge with outpatient testing include no recurrent chest pain after 6-12 hours of observation, normal or unchanged ECG on serial testing, two negative troponin measurements, and no high-risk features present, as recommended by the American College of Cardiology 2, 3

The American College of Cardiology advises against relying on a single troponin measurement if drawn less than 6 hours from symptom onset, as myocardial injury may not yet be detectable 3
The American College of Cardiology recommends against starting thrombolytics without clear ST-elevation or new left bundle branch block on ECG, as this causes harm in non-STEMI patients 1
The American College of Cardiology suggests against starting lidocaine infusion empirically, as it is not indicated for chest pain evaluation and is reserved for specific ventricular arrhythmias in the setting of acute MI 1

When cardiac causes are excluded, the American College of Cardiology recommends evaluating for aortic dissection, pulmonary embolism, pericarditis, pneumothorax, and esophageal disorders 1, 6, 4