1. ST-segment elevation >= 1 mm and concordant with QRS complex
2. ST-segment depression >= 1 mm in lead V1, V2, or V3
3. Slight controversy about the third rule:
   • Old: ST-segment elevation >= 5 mm and discordant with QRS complex
   • New: ST-segment to S-wave ratio <= -0.25. Or, ST segment discordant with the QRS complex by >= 25% of the amplitude of the QRS complex