| Intervals | Normal duration Average Range | Events in the Heart |
| PR interval | 0.18 0.12 to 0.2 | Atrial depolarization and conduction through AV node |
| QRS interval | 0.08 to 0.10 | Ventricular depolarization and Atrial repolarization |
| QT interval | 0.40 to 0.43 | Ventricular depolarization and repolarization |
| ST interval | 0.32 | Ventricular repolarization |
| P wave | | Atrial depolarization |
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