| Flap 1 |
Flap 2 |
| P-Wave | the sequential activation (depolarization) of the right and left atria |
| QRS Complex | right and left ventricular depolarization (normally the ventricles are activated simultaneously) |
| ST-T Wave | ventricular repolarization |
| P-R Interval | time interval from onset of atrial depolarization (P wave) to onset of ventricular depolarization (QRS complex) |
| QRS Duration | duration of ventricular muscle depolarization |
| QT Interval | duration of ventricular depolarization and repolarization |
| R-R Interval | duration of ventricular cardiac cycle (an indicator of ventricular rate) |
| P-P Interval | duration of atrial cycle (an indicator or atrial rate) |
