<prompt> PR interval in ECG shows?Ventricular depolarizationVentricular RepolarizationConduction through AV node.Atrial Repolarization  <response>: Normal ECG waves and Intervals: ECG waveInterval Characteristics 1. P Wave Reflects Atrial Depolarization activation 2. QRS complex Depolarization of ventricles 3. T Wave Repolarization of ventricles 4. PR Interval Atrial depolarization and conduction through AV node 5. QT Interval Total duration of Ventricular depolarization and repolarization 6. ST segment Plateau phase of ventricular action potential 