STEMI typically defined by:
≥1 mm (0.1 mV) ST segment elevation in limb leads
≥ 2 mm ST segment elevation in precordial leads
Findings present in at least 2 anatomically contiguous leads
Several variations from the classic STEMI ECG changes are similarly concerning and considered 'STEMI<unk> 
≥1 mm (0.1 mV) ST segment elevation in limb leads
≥ 2 mm ST segment elevation in precordial leads
Findings present in at least 2 anatomically contiguous leads
STEMI equivalents
STEMI mimics
Stable angina
Vincent's angina
Unstable angina
AVR ST elevation
T wave changes
Unstable Angina - NSTEMI Guidelines