ECG Diagnosis of Inferior Wall Myocardial Infarction

Diagnostic Criteria

The European Society of Cardiology recommends that ST-segment elevation ≥1 mm in at least two contiguous inferior leads (II, III, aVF) is the hallmark finding that confirms acute inferior MI and warrants immediate reperfusion therapy 1, 3
The American Heart Association suggests that acute pericarditis presents with diffuse ST-segment elevation across multiple leads with characteristic PR-segment depression, not isolated inferior lead changes, with ST elevations typically concave upward and widespread 2, 4, 5, 6

The European Society of Cardiology advises obtaining the ECG within 10 minutes of presentation when acute coronary syndrome is suspected, as this is the critical time window for diagnosis 1, 2
Serial ECGs at 15-30 minute intervals are essential if the initial tracing is non-diagnostic but clinical suspicion remains high, according to the American Heart Association 2
The European Society of Cardiology recommends comparing with prior ECGs when available, as pre-existing Q waves from old inferior MI can complicate interpretation 4, 5

Deep symmetrical T-wave inversions in inferior leads without ST elevation may represent a prior inferior MI rather than acute ischemia, as suggested by the European Heart Journal 3, 5
A completely normal ECG does not exclude acute coronary syndrome, as approximately 5% of patients with normal ECGs ultimately have MI or unstable angina, according to the European Heart Journal 4, 5